Winradio Advanced Digital Suite instruction manual

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WiNRADiO

Advanced Digital Suite

Version 1.0

User’s Guide

WiNRADiO Advanced Digital Suite User’s Guide

Published by WiNRADiO Communications 15 Stamford Road, Oakleigh 3166, Australia

of the publisher.

Trademarks

WiNRADiO, Digital Suite, Advanced Digital Suite, V isiTune, XRS and associated logos are trademarks or registered trademarks of WiNRADiO Communications.

All other brand and product names are trademarks or registered trademarks of their respective owners.

Patents

Certain aspects of WiNRADiO technology may be protected by US patent no. 6,289,207 and other US and international patents or pending applications.

Printed in Australia

WiNRADiO Advanced Digital Suite User’s Guide

Limitation of Liability and Remedies The information published in this book has been compiled from several sources. While every

effort has been made to ensure its accuracy , neither the authors nor the publisher can guarantee that all information is entirely correct or up-to-date. Furthermore, neither the authors nor the publisher can take any responsibility for the use of this information or any consequences arising therefrom.

WiNRADiO Communications shall have no liability for any damages due to lost profits, loss of use or anticipated benefits, or other incidental, special or punitive damages arising from the use of, or the inability to use, the WiNRADiO receiver or this optional software, whether arising out of contract, negligence, tort or under any warranty, even if WiNRADiO Communications has been advised of the possibility of such damages. In no event shall WiNRADiO Communications’ liability for damages exceed the amount paid for this product. WiNRADiO Communications neither assumes nor authorises anyone to assume for it any other liabilities.

Warning In certain countries or states it is illegal to listen to certain frequencies, such as police or

cellular telephones. We cannot accept any responsibility for the consequences of your noncompliance with government regulations. If you are in doubt about the regulations in your country or state, please contact your nearest radio communications regulatory authority.

WiNRADiO softwar e is periodically upgraded. If you wish to be automatically notified of upgrades and other WiNRADiO related information, please register with our user database. Visit www.winradio.com/subscribe. For information about new products please visit our Web site www.winradio.com frequently.

WiNRADiO Advanced Digital Suite User’s Guide

Table of Contents

Introduction........................................................................................................... 7

Installation............................................................................................................. 9

System Requirements ........................................................................................... 9

Hardware Installation .......................................................................................... 9

Software Installation ............................................................................................ 9

Using The WiNRADiO Advanced Digital Suite .............................................. 1 0

Sound Card Setup ............................................................................................. 10

Troubleshooting ............................................................................................... 15

Audio Scope and Audio Spectrum Analyzer..................................................... 1 6

Setting up the Scope and Spectrum Analyzer .................................................. 16

Recorder and Player ........................................................................................ 17

Audio Scope ..................................................................................................... 18

Audio Spectrum Analyzer ................................................................................ 23

FTT (Fourier Transform) W indow................................................................... 26

Waterfall Spectrum Analyzer .......................................................................... 28

Other Waterfall controls: ................................................................................ 2 8

Advanced ACARS Decoder................................................................................. 33

Decoder Setup .................................................................................................. 3 4

Audio ACARS Signal Playback........................................................................ 36

Advanced Audio Signalling Decoder ................................................................ 3 7

Alarms Configuration ...................................................................................... 39

Alpha Tags Configuration ................................................................................ 40

Advanced Fax Decoder ....................................................................................... 4 1

Received Image ................................................................................................ 42

Decoding Engine Setup.................................................................................... 43

Demodulator Selection .................................................................................... 4 4

Reference Clock Extraction ............................................................................ 4 4

Automatic Image Receiving............................................................................. 45

Horizontal Synchronisation ............................................................................. 4 6

Line Processing Regions ................................................................................. 4 7

Image Constructing Rules ................................................................................ 4 7

Digital Header Processing ............................................................................... 4 9

Signal Study...................................................................................................... 50

Image Study ...................................................................................................... 50

T ask Scheduler ................................................................................................. 51

WiNRADiO Advanced Digital Suite User’s Guide

Advanced NA VTEX Decoder .............................................................................. 52

Decoder Setup .................................................................................................. 5 3

WAV File Processing and Recording .............................................................. 56

NA VTEX Task Scheduler ................................................................................. 57

Advanced Packet Radio Decoder ...................................................................... 5 9

Decoder Setup .................................................................................................. 6 0

Advanced Signal Classifier ................................................................................ 6 1

Advanced Signal Conditioner ............................................................................ 6 3

Lowpass, Highpass, Bandpass or Bandstop filtering....................................... 65

Signal display in time and frequency domains ................................................ 68

The Marker Tone.............................................................................................. 70

Noise reduction ............................................................................................... 7 1

Tone Interference Rejection ............................................................................ 7 3

Pitch shifting .................................................................................................... 7 5

Output signal level control .............................................................................. 7 6

Speech inversion .............................................................................................. 7 7

Configuration saving and retrieving................................................................. 78

Recording a processed signal .......................................................................... 7 8

Processing of a recorded signal ...................................................................... 7 9

Advanced Squelch Controlled Recorder ......................................................... 8 1

Supported Audio Formats ................................................................................ 8 2

Audio Processing Tools ................................................................................... 8 3

Handling the Audio File ................................................................................... 84

Contact Us ............................................................................................................ 8 5

Index ...................................................................................................................... 86

WiNRADiO Advanced Digital Suite User’s Guide7WiNRADiO Advanced Digital Suite User’s Guide

Introduction

The WiNRADiO Advanced Digital Suite is a collection of digital signal processing modules, which fully integrates with WiNRADiO receivers and brings digital signal processing of radio signals to a new advanced level.

The WiNRADiO Advanced Digital Suite contains the following facilities:

• WEFAX and HF Fax Decoder

This module will decode weather fax transmissions from orbiting weather satellites as well as HF Fax from land stations. Received images are decoded and displayed in real time, and received transmissions can be recorded and played back. Advanced decoding and image processing methods are used to display images with maximum clarity. A programmable task scheduler allows you to receive images with the receiver unattended.

• NAVTEX Decoder

The NA VTEX Decoder makes it possible to receive maritime safety , navigational and weather information.

• Packet Radio Decoder

The packet radio decoder implements the AX.25 standard and enables the reception of amateur packet radio transmissions.

ACARS

The ACARS (Aircraft Communications Addressing and Reporting System) is an aviation information network used by all major airlines. This ACARS decoder also contains a translator for airline-specific messages, an extensive database of over 1200 airlines, and over 10800 airports, including both IATA and ICAO codes.

Advanced Signal Classifier

The Signal Classifier will analyze the received signal and classify it into one of several categories (voice, data, silent channel or noise), which can increase the scanning speed of the receiver.

Advanced Audio Scope and Audio Spectrum Analyzer

This module includes an advanced audio storage oscilloscope, waveform grabber and spectrum analyzer. It is suitable for analysis of demodulated audio signals from DC to 20 kHz. The spectrum analyzer employs an advanced FFT algorithm based on an optimized CPU code which provides real time spectrum analysis with excellent responsiveness. A waterfall analysis function is also included.

WiNRADiO Advanced Digital Suite User’s Guide

Advanced Audio Recorder

This squelch-controlled recorder will record and playback audio signals using user-selectable codecs, bit lengths and sampling rates. The recorder also includes additional advanced facilities such as pitch shift and playback speed control.

Audio Signalling Decoder and Logger

This decoder will handle CTCSS and DTMF signalling at the same time. This is useful in situations where DTMF signalling is used on CTCSS activated transmitters, and switching between two decoders would cause loss of data. The Audio Signalling Decoder also includes comprehensive alarm management, where user-specified CTCSS tones and DTMF strings can generate an alert. All communications can be recorded and logged.

Advanced Signal Conditioner

This module contains a number of user-defined digital filters, adaptive noise reduction, auto-notch and other advanced functions. This is supplemented with a spectrum analyzer demonstrating the immediate effects of the various filtering options.

Installation System Requirements

Processor: Pentium 300MHz RAM: 32MB Display SVGA: 800x600, 256 colors OS: Windows 98, 2000, ME, NT or XP Free Disk Space: 30M B Soundcard: 16 bit Soundblaster compatible card Receiver: Any W iNRADiO receiver Receiver software: XRS compliant (version 3.46 or above for

Hardware Installation

1. For DSP-enabled WiNRADiO receivers, no hardware installation is necessary.

2. For non-DSP receivers (using a sound card), plug the supplied connection lead into the audio jack of the WiNRADiO card and to the ‘Line In’ jack of your sound card. If no line in jack exists on your PC, use the microphone input. We str ongly recommend that you connect

the lead with the computer switched off to avoid any static discharges, which could result in damage to your computer.

Connect headphones or external amplified speakers to your sound card speaker output.

WiNRADiO Advanced Digital Suite User’s Guide

1000/1500 WiNRADiO series, or 2.46 or above for 3000/3100 WiNRADiO series)

Software Installation

1. Insert the installation CD ROM.

2. Follow the automatic installation process. If auto-start is disabled on your PC, run the install.exe program on the CD ROM manually.

3. Start up your WiNRADiO receiver. The Advanced Digital Suite will appear in the main menu.

WiNRADiO software is periodically upgraded. Check out the newest software version on our Web site at www.winradio.com. If you wish to be automatically notified of upgrades and other WiNRADiO related information, please register with our user database using our subscription facility on www.winradio.com/subscribe.

WiNRADiO Advanced Digital Suite User’s Guide

Using The WiNRADiO Advanced Digital Suite

When you start up your WiNRADiO receiver , the Advanced Digital Suite appears in the main menu. The facilities of the WiNRADiO Advanced Digital Suite are mutually exclusive, which means you can run only one of them at a time.

Sound Card Setup

The Advanced Digital Suite automatically detects the WiNRADiO receiver type. Models with a built-in DSP do not require any set-up and this section is not relevant to this type of receiver.

Receivers without a DSP need to use a sound card for the Advanced Digital Suite to function, for which purpose the control panels of each Advanced Digital Suite facility will contain additional “wave device” set-up.

“Windows default” is the Control Panel setting specified under Start | Settings | Control Panel | Sounds and Multimedia | Properties | Audio. If a sound card is specified in this Control Panel setting for both playback and recording (likely, but not always necessarily so), then you can simply select Windows Default as the wave device for the demodulator. Otherwise, the specific name of the sound card should be selected.

The next parameter to select is the mixer device associated with the already selected sound card, using the Mixer device in use drop-down list.

WiNRADiO Advanced Digital Suite User’s Guide

If the signal is arriving to the sound card via an external cable, the cable should be preferably connected to the Line input of the sound card. This input must also be selected in the Mixer Line in use drop-down list (see the ACARS example above) and also in the Recording Control of the sound card control panel.

To get to the Recording Control, bring up the sound card control panel first (by clicking on the speaker symbol located on the right in the bottom toolbar). You will get the sound card playback volume control, which will look similar to this (may be slightly different on your PC):

Make sure that the Line Input is unmuted, then mute all the others except of course the main playback on the far left. Then you need to select Options | Properties in the top bar menu, and you will get the following panel:

WiNRADiO Advanced Digital Suite User’s Guide

Now check Recording and click OK. You will get the Recording Control which will typically look like this.

Now check the Line Input and leave all the others unchecked.

Some PCs (especially laptops) may not have the Line Input. In such case use Microphone input instead, and make sure it is selected in all three instances: The Advanced Digital Suite, and the sound card playback and recording control panels.

If you are using the Microphone input then you need to check if your sound card recording control panel has an Advanced button next to the volume setting.

If so, then click on the button, to reveal a panel containing an optional gain switch.

WiNRADiO Advanced Digital Suite User’s Guide

Make sure the gain setting is unchecked, otherwise the signal will be too strong and the sound card will get overloaded.

For best decoding and signal processing results, the audio signal level should be as high as possible, but not to the point of overloading. It is recommended that the receiver volume should be kept rather low, and the signal level volume should be adjusted to the maximum using the sound card recording volume. In the following example, the recording volume is set to maximum.

The best method is to set the sound card recording volume to the maximum level, and then reduce the receiver level to the point when no “clipping” occurs. Clipping occurs when the signal is too high and distortions may result. The various decoding and signal processing facilities of the Advanced Digital Suite have their own clipping indicator which turns red if clipping occurs. It may also be useful to adjust the signal level by observing it on the Audio Oscilloscope, and adjusting it so that the waveform has maximum amplitude but without turning on the clipping indicator:

WiNRADiO Advanced Digital Suite User’s Guide

Some of the Advanced Digital Suite functions have their own convenient Audio Signal Level indicators. For optimum processing, these should be somewhere between 60% and 70% of the full scale. When the signal peaks turn red, this indicates that the level is too high and distortions (causing decoding errors) may result. The following example shows the Advanced Signalling Recorder and the Audio Level (shown at top right) is optimum:

WiNRADiO Advanced Digital Suite User’s Guide

Troubleshooting

The most frequent problems with the Advanced Digital Suite when used with the sound card are caused by one of the following:

• Receiver output is not connected to the Line Input.

• Receiver volume is not sufficient.

• Sound card volume is not sufficient, or the recording mixer is not enabled for Line Input.

• Sound card output is muted. Firstly, make sure you can actually hear the radio via the sound card (without the

Advanced Digital Suite involved) - connect the receiver speaker output to the sound card Line input, and the speaker to the sound card speaker output. You should be able to hear the radio. If not, you need to enable the sound card Line Input, or unmute it, in the sound card control panel.

It is very important that you use the RECORDING line input for any volume adjustments. The sound card Recording panel is hidden, under Options | Properties | Recording of the main sound card volume control panel top bar menu.

Use the Audio Oscilloscope to see the signal and adjust the volumes (both on the receiver panel, and Line input in the sound card recording control panel) to maximum level just before clipping occurs. All other functions of the Advanced Digital Suite should then work correctly.

For decoding ACARS, NAVTEX and other signals, it is advisable to keep the receiver volume lower rather than higher, and make up for the total level needed by adjusting the sound card recording volume (this is to avoid overloading of the sound card input).

WiNRADiO Advanced Digital Suite User’s Guide

Audio Scope and Audio Spectrum Analyzer

The WiNRADiO Audio Scope and Spectrum Analyzer is a sophisticated analysis tool for audio waveforms demodulated by a WiNRADiO receiver, both in time and frequency domains.

Using this tool is quite intuitive; all of its controls are grouped together in five basic functions:

• Set-up

• Recorder and Player

• Scope

• Analyzer

• Waterfall

Setting up the Scope and Spectrum Analyzer

The Advanced Audio Scope and Spectrum Analyzer automatically detects the WiNRADiO receiver type. This determines what you will see at the top of the set-up panel. Models without a built-in DSP will need to use a sound card for the software to function, for which purpose the panel will contain parameters relating to the the “wave device” set-up:

Set-up for a DSP receiver

Set-up for a sound card

No set-up is necessary for DSP-based WiNRADiO receivers. For non-DSP receivers, use the installation information on page 10-15.

WiNRADiO Advanced Digital Suite User’s Guide

Recorder and Player

The WiNRADiO receiver audio output can be recorded in a W indows PCM WAV file format (mono, 16bits, 44100Hz sampling rate), or you can playback an already existing WAV file as follows:

• Firstly, the file location has to be selected in the Setup panel. The standard Windows Open File dialog box opens when the (…) button is pressed. After selection, the file name will appear in the Input/Output WAV window. You can type the file name directly into this window. If the opened file contains a recorded signal, the plug-in automatically verifies its format.

• Start recording. As long as this button is pressed, the signal samples are added to the file, and the time elapsed from the beginning of the recording is displayed in the hours-minutes-seconds format.

• Start playback. The time elapsed from the beginning of the recording, and also the total length of the recording are displayed in the hours-minutes-seconds format.

• Pause recording or playback.

• Stop recording or playback. When the player is stopped,

the Audio Scope and Spectrum Analyzer automatically starts to display the real-time signal from the WiNRADiO receiver.

• Jump in steps towards the beginning or to the end of a record. In record mode, the signal samples will be overwritten.

• Walk through a recording using the progressive track bar. In record mode, the signal samples will be overwritten.

An already opened WAV file will be automatically closed when a new one is opened or when the application ends.

The wave recorder-player function is also available in Scope or Analyzer modes.

WiNRADiO Advanced Digital Suite User’s Guide

Audio Scope

The Scope is a classic instrument to study signal waveforms in the time domain. The tools associated with this function offer a large range of possibilities familiar to those acquainted with any analog or digital single channel oscilloscope.

The Scope controls are:

Trace Type

Trace type can be changed from interpolated Lines to Points or Bars.

Grid button

Grid button enables the horizontal and vertical line grid in the waveform viewing area.

WiNRADiO Advanced Digital Suite User’s Guide

d/dt button

d/dt button displays the time derivative of the input signal. This is a very useful tool when analyzing transitions in a digital signal. Instead of displaying the direct flow of a signal s(t), its time derivative ds(t)/dt is shown. The faster the signal changes the higher the value of the derivative - making it possible to view modulation changes very easily.

Timebase

Timebase determines the displayed waveform duration. Each horizontal division of the waveform viewing area can be made to correspond to a time interval ranging from 100µs up to 100ms, following a 1-2-5 rule.

Trigger

Trigger buttons control the starting conditions for displaying the signal in several exclusive modes. In Free mode the scope continuously sweeps. When Single Shot mode is activated, a single signal trace is obtained every time the button Reset is pressed.

WiNRADiO Advanced Digital Suite User’s Guide

All other modes are signal-dependent, which means that the signal has to fulfill a certain condition in order for its waveform to be displayed. In the Level mode the waveform sampling is synchronized the instant its value equals the one pointed at by the red triangle. You can drag the trigger level, with the left mouse button pressed, anywhere between the two limits of the display window. Choosing the +edge or -edge triggering mode, the waveform sampling is synchronized with the rising or falling edges of the signal passing through the marked level. A special case is the Squelch controlled trigger, which enables the waveform display only if the received signal level is above the threshold determined by the squelch control in the WiNRADiO receiver virtual panel.

Time markers

One or two Time markers can be activated in the waveform display window. The corresponding time values of the markers and the difference between these values are displayed at the bottom of the window. Every new marker appears at the left edge of the display window and you can drag a marker with the left mouse button pressed.

WiNRADiO Advanced Digital Suite User’s Guide

Vertical scale

Vertical scale varies the scaling ratio to stretch lower amplitude signals over the entire vertical range of the waveform viewing area. Scaling ratio can be changed between 1 and 10, but you need to watch the Clipping indicator which will be activated (its color will turn to red) when the input signal amplified waveform exceeds the display limits.

Memory function

Memory function makes it possible to study the periodicity of a signal, especially in data transmissions. As long as the associated Reset button is not activated, all the signal waveform traces remain visible in the display area. A level or edge controlled trigger is recommended in this mode.

WiNRADiO Advanced Digital Suite User’s Guide

Pause

A Pause in the waveform display refresh is useful if the displayed signal needs to be “frozen in time” on the screen and analyzed (for example using time markers). A wave recorder-player is included for saving WiNRADiO receiver output in the W indows PCM W AV file format (mono, 16bits, 44100Hz sampling rate), or retrieval of a stored wave shape from an already existing WAV file.

WiNRADiO Advanced Digital Suite User’s Guide

Audio Spectrum Analyzer

The Analyzer is implemented using an advanced FFT algorithm and is useful for analysis of audio spectrum ranging from DC to 20kHz if using the sound card, or DC to 10kHz if using the DSP. The dynamic range is given by the quality of the sound card in use, or the DSP unit.

The Analyzer controls are:

Trace type

Trace type can be changed from interpolated Lines to Points or Bars.

Grid button

Grid button enables the horizontal and vertical line grid in the spectrum viewing area.

WiNRADiO Advanced Digital Suite User’s Guide

Linear spectrum display

Linear spectrum display may be preferable for strong audio input signals.

Averaging

A veraging helps to emphasize those spectral components which have a pronounced stationary character. Pressing the corresponding button turns averaging on. The averaging effect is controlled by the averaging coefficient which can be either directly typed in the associated edit box, or selected using the up/down arrows or the small slide between the arrows. A lower value will reduce the contribution of the current signal spectrum to the displayed averaged spectrum.

Trigger

Trigger buttons control the starting conditions for displaying the signal spectrum in two non-exclusive modes. In the Squelch controlled trigger mode, the spectrum display is enabled only if the received signal level is above a threshold determined by the squelch control in the WiNRADiO receiver virtual panel. When the Single shot mode is activated by pressing the corresponding button, a signal spectrum is displayed every time the button Reset is pressed.

WiNRADiO Advanced Digital Suite User’s Guide

Sweep range

The Sweep range controls make it possible to extend or narrow down the frequency interval within which the spectrum is computed. The range is defined by its Start and Stop limits, or its corresponding Center frequency and Width. These four parameters are related.

Frequency markers

There are eight Frequency markers which can be activated in the spectrum display window. The corresponding frequency values of the markers are displayed at the bottom of the window. Every new marker appears at the left edge of the display window and the user can drag a marker with the left mouse button pressed.

Baseline clipper

A Baseline clipper mechanism is implemented to emphasize only those spectral components which have a greater level than the one corresponding to the baseline. You can drag the baseline up and down, keeping the mouse left button pressed, up to the desired relative power level.

Pause

A Pause in the spectrum display refresh is useful if the currently displayed spectrum needs to be examined. As long as you keep this button pressed, you can use frequency markers and the baseline clipper. A wave recorder-player is included for saving WiNRADiO receiver audio output in a W indows PCM WAV file format (mono, 16bits, 44100Hz sampling rate), or retrieval of a recording from an already existing WAV file.

WiNRADiO Advanced Digital Suite User’s Guide

FTT (Fourier Transform) Window

The Fourier transform is used to determine the spectrum of a signal from its samples. Normally, such transform should be applied to an infinitely lasting signal, which is achievable only in the realm of mathematical formulas. This is not feasible in the real world: firstly, the sampled signal does not last for an infinitely long period of time, and secondly, an infinite period of time is not available for such computations.

The FFT (Fast Fourier Transform) is an algorithm that requires a number of samples equal to a power of two. Using such a finite number of samples results in an incorrect spectrum display, with over-emphasised components of higher frequencies. The FFT result is correct only if the samples provided at its input correspond to any combination of frequencies with periods equal to integer submultiples of the number of input samples, up to the Nyquist frequency. (Note:

A “submultiple” is a number that divides another number without remainder; for example 3 is a submultiple of 6, 9 and 12; but not 5, 10, or 11.)

To correct the effects of the fact that the observed signal has a definite start and end, the input samples can be subject to a “windowing function” before the FFT algorithm is applied. This windowing function reduces the effect of the abrupt start and stop of the examined signal by setting the initial and final samples to zero, making the examined signal appear periodic. These windowing functions can greatly improve FFT results. There are several types of such windowing functions. None is suitable and ideal for all circumstances, that is why a selection of these functions has been provided. The trade-offs between the windowing functions can be best described in terms of resolution accuracy (of which a low value make spectral lines appear wider), spectrum leakage (of which a large level can compromise the ability of distinguishing lower spectral components in the presence of high-level ones), and amplitude and frequency accuracy.

As demonstrated in the next pictures, in which the sampling rate was 22050Hz and the tone frequency was 1kHz, the Rectangle and Triangle windowing functions yield a very bad result in this case. Cosine, Hamming and Blackman windowing functions provide almost identical results, but there are situations when one of them performs much better than the others for a given input signal: If the studied signal has a frequency equal to a submultiple of the sampling rate, the Rectangle window is the best, by far, as the result is almost similar to a vertical line at that frequency. Generally, the Blackman windowing function can be recommended for most typical situations, even though if it has the tendency to show pure tones with somewhat wider spectral lines.

WiNRADiO Advanced Digital Suite User’s Guide

Waterfall Spectrum Analyzer

The Waterfall Spectrum Analyzer makes it possible to display a spectrum evolution in time.

Each new horizontal line of the display window represents a new spectrum trace; every point of the line corresponds to a particular freqency and its color to the signal level. The range of signal levels is divided in 20 steps, each of them 5dB wide. The default color for the reference step (0dB) is white and that for the lowest one is black. The gray scale between extreme levels can be easily changed by the user:

1) Place the cursor above the level whose color you wish to change.

2) Click the left mouse button and the Color Picker window will pop up.

3) Drag the three vertical sliders to obtain the desired color in the color sample window.

4) Press the OK button when you are satisfied with the new color, otherwise you can go back to the initial color by pressing the Cancel button.

Other Waterfall controls:

Colors reset

Can be pressed to go back to the default gray level scale.

Interpolate

A gradual change of colors between those corresponding to the extreme levels can be obtained when the Interpolate function is activated:

WiNRADiO Advanced Digital Suite User’s Guide

Inverse

The Inverse function turns the color scale upside-down:

Linear spectrum display

Linear spectrum display may be preferable for strong audio input signals. This mode is enabled by pressing the corresponding button. The meaning of this feature becomes more clear in the Analyzer mode.

FFT Window

FFT Window as explained earlier.

Averaging

A veraging helps you to emphasize spectral components which have a pronounced stationary character. After pressing this button, an averaging coefficient must be selected or directly typed. A lower value for the averaging coefficient will reduce the contribution of the current signal spectrum to the displayed averaged one. The meaning of this feature becomes more clear in the Analyzer mode.

Waterfall spectrum display types

For optimum signal survey, three types of Waterfall spectrum display are available and activated by the associated buttons: 2D waterfall, 3D waterfall with Fade away or Perspective options, and 3D color waterfall. The pictures below show the differences between these methods of viewing the signal spectrum history.

WiNRADiO Advanced Digital Suite User’s Guide

2D waterfall

3D waterfall

3D waterfall-fade away

3D waterfall-perspective

3D colour waterfall

WiNRADiO Advanced Digital Suite User’s Guide

Sweep range

Frequency marker

Up to eight Frequency markers can be activated in the spectrum display window. The corresponding frequency values of the markers are displayed at the bottom of the window. Every new marker appears at the left edge of the display window and you can drag a marker with the mouse left button pressed.

WiNRADiO Advanced Digital Suite User’s Guide

Baseline clipper

A Baseline clipper function is implemented to emphasize only those spectral components having a greater level than the one corresponding to the baseline. You can drag the baseline up and down to the desired relative power level by keeping the mouse left button pressed.

Pause

A Pause in the spectrum display refresh is useful if the current display needs to be “frozen in time” and examined. While the display is paused, you can use the frequency and time markers.

Time markers

One or two Time markers can be activated in the waterfall display window. If more than one marker is activated, the corresponding time difference between the markers is displayed. Every new marker appears at the left edge of the display window and you can drag a marker to its required position with the left mouse button pressed.

WiNRADiO Advanced Digital Suite User’s Guide

Advanced ACARS Decoder

ACARS is an air/ground network which enables an aircraft to function as a mobile computer terminal, with links to ground control stations. ACARS stands for Aircraft Communications Addressing and Reporting System.

The WiNRADiO ACARS Decoder is a complex XRS plug-in dedicated to those interested in monitoring ACARS activity in real time, using any WiNRADiO receiver (with or without DSP, internal or external).

Although most major airlines use this system, only parts of the transmission protocol are standardized or publicly accessible. This ACARS decoder implementation allows decoding of several common types of messages, while leaving unrecognized parts in a plain text form, as received.

To be able to extract details from the received information, the decoder contains the following:

• An extensive list of commonly used message labels and their description.

• Airline-specific message labels for certain common messages.

• A complete list of all countries.

• An extensive list of over 1200 airlines, both with IATA and ICAO codes.

• An extensive list of over 10800 airports, including both IATA and ICAO codes. The ACARS transmissions use AM modulation. To receive ACARS, select the

AM mode and tune the WiNRADiO receiver to a frequency within the aircraft band (118 to 136 MHz). The most likely frequencies for ACARS are:

• 129.125 MHz (tertiary channel for USA)

• 130.025 MHz (secondary channel for USA)

• 130.450 MHz (additional channel for USA)

• 131.450 MHz (primary channel for Japan)

• 131.475 MHz (private company channel for Air Canada )

• 131.525 MHz (secondary channel for Europe)

• 131.550 MHz (primary channel for USA, Canada and the Pacific Rim)

• 131.725 MHz (primary channel for Europe)

WiNRADiO Advanced Digital Suite User’s Guide

The ACARS transmissions appear in bursts, with no more than 220 characters per message. Because transmissions often last less than one second, do not use squelch when running the ACARS decoder with a WiNRADiO receiver without a DSP (i.e. keep its value down to 0). The squelch delay would cause critical losses of data, resulting in unrecognized or erroneously decoded transmissions.

Decoder Setup

The Advanced ACARS Decoder automatically detects the WiNRADiO receiver type. This determines what you will see at the top of the main control panel. Models without a built-in DSP will need to use a sound card for the software to function, for which purpose the control panel will contain the “wave device” setup.

No set-up is necessary for DSP-based WiNRADiO receivers. For non-DSP receivers, use the installation information on page 10-15.

For all types of WiNRADiO receivers the rest of the decoder panel looks identical.

The decoded messages are displayed in the panel main window and at the same time can be written into a text file if the Log file button is pressed. The file name has to be manually typed or selected using the standard Windows Open file dialog, which is opened by clicking on the “three dots” button. The saved messages are accompanied by their corresponding time and date, in the preferred Log date format.

WiNRADiO Advanced Digital Suite User’s Guide

Detailed information about decoded transmissions is displayed when the corresponding buttons Registration, Label , Message no., Flight ID and Message are pressed. Under poor receiving conditions, select the Parity filter or even the Syntax filter , to eliminate erroneously decoded transmissions.

Otherwise, if an error is detected while decoding a certain character, that character will be displayed in red.

WiNRADiO Advanced Digital Suite User’s Guide

Audio ACARS Signal Playback

Irrespective of the wave device, the decoder panel contains a waveform playback control, with familar functions.

When tuned to an ACARS VHF frequency , the WiNRADiO receiver audio output can be recorded in a Windows PCM WAV file format, 44100 samples per second with 16 bits per sample, using any available wave recording software. You can then run the decoder “off-line”, playing back the WAV file, as follows:

Specify the file name and its location. The standard Open File dialog box opens when the button marked with three dots (…) is pressed. After selection, the file name will appear in the edit window. Alternatively, type the file name directly into this window. The decoder automatically verifies the correct format of the wave file.

Start playing the WAV file. The time elapsed from the beginning of the recording and also the total length of the recording are displayed in the hours-minutes-seconds format. The decoded ACARS transmissions appear in the panel main window, according to the decoder settings (refer Decoder setup).

Pause the playback. If very dense traffic was recorded it is useful to be able to pause the decoding process in order to look at the decoded messages.

To step forward or backward, use the two respective buttons marked with double arrows.

To walk through the recording, use the progressive track bar.

To stop the player, press the button marked with a green square. When the player is stopped, the ACARS decoder automatically starts to process the real-time signal coming from the WiNRADiO receiver.

An already opened WAV file will be automatically closed when a new one is opened or when the decoder session ends.

WiNRADiO Advanced Digital Suite User’s Guide

Advanced Audio Signalling Decoder

The Advanced Audio Signalling Decoder makes it possible to handle CTCSS and DTMF signalling at the same time. This is useful in situations where DTMF signalling is used on CTCSS activated transmitters, and switching between two different decoders would caused loss of data. The Audio Signalling Decoder also features a comprehensive alarm management, based on detected CTCSS tones and decoded DTMF strings.

The Decoder can be used either with any WiNRADiO receiver model and a sound card, or with a DSP-based WiNRADiO receiver where the DSP replaces the sound card for better performance. The decoder automatically detects the WiNRADiO receiver capability and configures its interface accordingly. If a sound card needs to be used, there will be selectors for wave-in and mixer devices and mixer inputs (refer to page 10 for setup information). There is also an Audio level indicator to simplify the recording volume setting, and to avoid clipping conditions:

WiNRADiO Advanced Digital Suite User’s Guide

When a CTCSS tone is detected, the corresponding button will change the caption colour to white. If one or more CTCSS buttons are pressed and the Squelch facility is enabled, the user will hear only those communications that use the selected CTCSS tones. If such filtering condition is activated, only those alarm conditions that pass through will be detected. For fast selection, the All and None buttons have been added.

The buttons Set Alpha and Alpha serve to set alphanumeric tags (aliases) for the CTCSS frequencies, and enable these aliases to be displayed on the buttons instead of the frequency values.

All CTCSS events can be logged in the general log file if the Log button in the CTCSS section is pressed.

The decoded DTMF codes are displayed in the DTMF section. The DTMF text display can be cleared using the Clear button. The decoded tones can be logged, line by line, in the general log file, if desired. Also the minimum length accepted for DTMF tone decision can be configured, in steps of 11.6ms. A normal value, for 50ms standard DTMF tones, is 5.

WiNRADiO Advanced Digital Suite User’s Guide

The desired log file name, including the path, needs to be specified using the Log file edit box and file browser. If the file already exists, the new log entries will be appended to the end of the file. The date format to be used in the log file is user selectable. There are six available date formats, the ones considered to be most likely.

The buttons Set Alarms and Enable Alarms may be used to specify alarm conditions and enable/disable alarms, respectively.

Alarms Configuration

This facility makes it possible to define alarm conditions, using both the detected CTCSS tone and a DTMF sequence mask. If the alarm conditions are met, there are three possible outcomes, and any combination of these can be selected.

For setting of the CTCSS tone condition, there are buttons associated with every CTCSS tone. They can all be enabled or disabled using the All and None buttons. If no button is activated, then the CTCSS condition will always be met. If all buttons are checked, than the CTCSS condition will be met only if there is a valid CTCSS tone. In any other case, the CTCSS condition will be met only if the detected tone is one of the selected ones.

For DTMF alarm conditions, the desired DTMF text string needs to be specified. There are several situations that can be defined here. Firstly, any match of the specified string in any continuous sequence of DTMF codes can trigger the alarm. Secondly, there is an exact match option, in which the defined DTMF sequence must be at the start of the decoded transmission. Thirdly, a wildcard character, ‘?’, can be used to ignore a DTMF code in its position.

WiNRADiO Advanced Digital Suite User’s Guide

When an alarm condition is encountered, this may trigger one (or more) of the following actions:

1. Start an audio recording of the received signal. The recording will use 11025Hz sampling rate, mono, 16 bits per sample format. The file name can be either manually entered or selected using the file browser button. The recording will proceed while the CTCSS condition remains valid, or for a user-specified time, or while the radio signal level remains above the squelch level. If any one of the three conditions is not met, the recording will stop.

2. Run an application. As the boundary between documents and applications is becoming blurred, mostly thanks to various scripting languages, even an HTML page can be specified as the application to be run. The application will be started for every occurance of the alarm condition.

3. Issue an alert message for the operator. This message is displayed in a message box that waits for the operator to close it.

The alarm conditions and the associated tasks can be named and stored. Such alarm sets can be added to, deleted or disabled, using the Add, Remove and Disable buttons, respectively. Each occurance of a CTCSS or DTMF signal is tested on all defined alarm sets in alphabetical order, and if one satisfies the alarm conditions, the rest will not be processed. If one or more of the defined alarm sets should be skipped, the Disable button should be used.

Alpha Tags Configuration

An “alpha tag” is a string of characters which can be associated with a CTCSS frequency. This facility makes it possible to define such alpha tags. The alpha tags can be grouped into sets, some of them usable on any frequency the receiver is tuned to, others only on specified radio frequencies. For tones that have no alpha tag defined, the CTCSS frequency (in Hz) will be displayed instead.

The alpha tag sets can be added, modified and removed as needed. If more sets are defined for a specific frequency, the first match will be used. A set can be disabled and, when all alpha tag sets are searched, the disabled set will be skipped.

Each alpha tag can have only up to 6 characters in length.If the If tuned to option is checked, this means that the alpha tag will only apply if the receiver is tuned to the frequency specified in the edit box next to it. To copy the current receiver

frequency into this box, click on Track receiver.

WiNRADiO Advanced Digital Suite User’s Guide

Advanced Fax Decoder

The Advanced Fax Decoder is suited for reception of orbiting satellites (WEFAX) and HF fax. The Decoder employs advanced decoding and image processing techniques to display received images with maximum clarity.

The Decoder is designed to work either with a DSP-based WiNRADiO receiver, or a non-DSP WiNRADiO receiver with the assistance of a sound card. If the DSP is present and the receiver is controlled by the WR-3xxx virtual panel, the decoder will take advantage of it, otherwise it will fallback to the sound card. For each of the two situations there is a different user interface in the setup page due to the additional settings required by the sound card: selections for the sound card, audio mixer and mixer line, together with the audio level indicator needed for correct volume setting. (Refer to page 10 for more information on soundcard settings).

The user interface consists of five panels, with controls grouped by functionality, and a separate section for WAV files recording and playback:

• Received image - displays the received images.

• Setup - contains most of the decoder settings.

• Signal study - contains controls for the signal analysis and some additional

decoder settings that can be tuned more easily using the displayed information.

• Image study - displays statistics of the image contents.

WiNRADiO Advanced Digital Suite User’s Guide

• Scheduler - makes a fully automated operation possible.

Received Image

The status of the decoding engine can be seen and manually controlled whenever necessary from this panel, which also shows the decoded fax image. The decoder will always be in one of the four following states:

• Standby - this is a neutral state when the input signal is displayed in the signal study interface panel and the decoder setting can be changed, but no decoding takes place. The only part of the decoder working in this state is the input signal amplifier.

• Wait for start - depending on the current settings, the decoder may be waiting for the AM carrier and/or the start tone sequence. There may be situations in which none of these are available for the decoded transmission and the program will just skip to the next state.

• Wait for sync - the decoder waits for line synchronisation pulses. There is a minimum number of correct line synchronisation pulses that must be received before deciding that the pass to the next state is safe (i.e. the decoded image will not be missing horizontal synchronisation).

• Receiving - this is the real image receiving state. With the proper image synchronisation sequence detected, the image is decoded and displayed line by line. If the signal carrier is lost, the decoder goes back to the Wait for start state.

The buttons corresponding to the four states are located above the received picture. They can also be pressed by the user at any given time with corresponding effects. Depending on the given decoder settings, pressing one of the status buttons might cause a transition to the next status (i.e. pressing the Wait for start button when there is no start sequence to wait for causes a subsequent jump to Wait for sync).

WiNRADiO Advanced Digital Suite User’s Guide

The received images can be saved at any time. The Decoder makes it possible to save the image independent of its state. This allows, for example, saving the evolution of a yet incomplete image. After saving an image, its content is not lost as new lines are continuosly appended to the already existing ones.

The displayed image can be zoomed in or out. The two buttons below the image can be used for this purpose, with the current zoom value being displayed between them. Zooming in does not distort an image that much, but zooming out usually does.

Decoding Engine Setup

This section of the decoder interface contains most of the settings, grouped by functionality. All these settings are stored in the predefined settings and can be retrieved at any time. This is the only part of the entire user interface that changes depending on the WiNRADiO receiver in use. For DSP receivers the top part of the page has no sound card and mixer setup controls.

WiNRADiO Advanced Digital Suite User’s Guide

Demodulator Selection

There are two demodulator types, AM and FM, with four AM structures, from very simple to very complex, required by some transmissions:

The FM-modulated data are used to generate a shade of gray between the black and white frequency as configured in the signal study page. Usually these frequencies are 1500Hz for black and 2300Hz for white.

The AM-modulated data typically use a carrier frequency of 2400Hz. The carrier frequency can be also set in the signal study page. This is the simplest version of the AM demodulator.

AM+PLL

This AM demodulator is using a PLL for carrier retrieval, working synchronously . The PLL settings are located under the Clock heading.

AM+PLL+Coh.Det

This AM demodulator uses a coherent detector for data extraction.

Chosing the correct demodulator type is very important for good image decoding.

AM+PLL+Compl.Det

This AM demodulator uses a complex detector for data extraction, the input samples being multiplied with quadrature tones at the carrier frequency. After a low pass filtering the data is extracted as modulus of the resulted complex number.

Reference Clock Extraction

The correct reference clock must be extracted from the received data. For AM modulated data, the clock is extracted from the signal carrier and can be maintained, optionally, with a PLL. For FM modulated data, the reference clock is relative to the synchronisation pulses.

The PLL (Phase Lock Loop) is implemented in order to maintain the clock reference. The PLL time constant can be set between 0 and 1. Small values ensure very stable clocks, with accurate detection, but the time to lock the loop might be rather long for transmissions with short start sequences. A high value will ensure fast clock synchronisation, but with a possible jitter.

WiNRADiO Advanced Digital Suite User’s Guide

For proper carrier frequency detection, the AFC (Automatic Frequency Control) has been implemented. Small values of the constant will provide accurate tuning, but with long response times, while high values will provide fast but inaccurate tuning.The AM carrier frequency can be entered manually in the edit box or graphically by dragging the marker displayed in the input signal spectrum.

The two FM tones, for black and white, can also be set both manually, using the corresponding edit boxes, or graphically, using the two markers in the spectrum display. Marker 1 relates to black and marker 2 corresponds to white. If the two frequencies are swapped, the picture will be shown in negative.

Automatic Image Receiving

For automatic entering of all the three decoding states (refer to the Received Image page), the Decoder needs to find a triggering sequence. This sequence can be determined by a complex set of conditions.

For AM modulated data, the decoder will always wait for the presence of a carrier. In order to decide that the carrier is present, its level must be above the specified value and this should be true for a specified minimum length of time. Depending on the signal quality, the default 9 second period might be too long or too short. For good signals even 3 seconds is a very good choice.

If the Decoder is in the receiving state and the AM carrier is not present for the specified amount of time (off period), then the Decoder will be forced back to the wait for start state.

WiNRADiO Advanced Digital Suite User’s Guide

For FM modulated data, the decoder will go through the wait for start state if no other starting condition is set.

After the data is extracted from the input signal, there is an extra condition that can be set: start tones. This is a single tone or a combination of two tones that must be present for a given length of time. If Enable Start 2 is selected, the decoder looks for the presence of a second tone to decide whether to start the image receiving or not. If Start 2: IOC/2 is selected, the second tone is not used to decide whether to receive the image or not, but rather to decide whether the image is full-width or half-width; the presence of the second start tone forcing the width to half.

Horizontal Synchronisation

When the decoder is in the wait for sync state, it is looking for one of the following synchronisation conditions in order to move on to the receiving state:

• Tone burst - The synchronisation condition is a tone burst of a given frequency. Its presence indicates the start of a line.

• B/W, W/B immediate - The line start is a marked by a fast black-to-white or white-to-black transition.

• B/W, W/B picture - This is similar to B/W, W/B immediate, but the line start is omitted to avoid displaying the black-to-white or white-to-black transitions. Picture content is also checked and, if there is no such content detected and the number of lines with valid synchronisation pulses has reached the maximum specified amount, the image receiving will be started anyway.

• B/W, W/B header - Synchronisation is extracted from the digital data encoded in the first line of the picture. This is always associated with the digital headers.

The synchronisation condition should be met for the minimum amount of lines before the image decoding starts. For digital headers, the number of synchronisation lines should be set to zero as the digital signature is present only on the first line of the image.

When the picture content is checked, the decoder looks for a white to black transition between two lines (the searched line range is white on the first line and black on all others). This rule can be reversed by activating the reverse content option.

WiNRADiO Advanced Digital Suite User’s Guide

Line Processing Regions

Some satellites transmit (on the same line) information from two different “channels” (e.g. half of the line represents the visible light and the rest corresponds to the IR domain).

In most cases these two virtual channels will split the line in half, but there are situations where a channel can take less than half of the line. As a general rule, these two regions should not intersect, nor any channel should exceed the line end. The start and end of each channel is adjusted using the control panel shown below.

Similarly, in the single channel mode, only a part of a line is used for the image.

Image Constructing Rules

This panel defines the way in which the virtual channel(s) are processed to obtain the final image. Each virtual channel passes through a level translation and an amplification, with four possible situations.

• Single channel, B/W image - the data is processed using the first set of (offset, amplify) values.

• Single channel, color image - the same data is fed through both processing units. The first (offset, amplify) set defines the luminance and the second one is for the chrominance.

• Two channels, B/W image - the information in the two channels, after processing, is added and the result is the luminance.

• Two channels, color image - By processing the first channel, luminance is obtained and the second channel provides the chrominance.

The formula used for the calculation of image brightness is as follows:

Signal = (Channel1+Offset1)*Amplify1 [+(Channel2+Offset2)*Amplify2] ImageBrightness = (1-Brightness)*Signal + Brightness*SQRT(Signal)

Channel 2 influences the image brightness only when the color option is switched off.

WiNRADiO Advanced Digital Suite User’s Guide

There are six display modes, three for B/W pictures and three for color ones.

1 bit Black&White

Limits the resolution of the calculated bitmaps to 1 bit. This mode is intended for shortwave weather charts.

4 bit Black&White

Limits the resolution of the black and white bitmaps to 4 bit (i.e. 16 steps) resolution.

8 bit Black&White

Black and white bitmaps with 8 bit (256 steps) resolution.

5 bit Brightness + 3 bit Color

Color bitmaps with 8 bit resolution. The 5 MSBs are used for brightness information (luminance), the 3 LSBs are used for color hue. The hue results from Hue=(Channel2+Offset2)*Amplify2. Smaller (positive) values result in red, larger (on a scale of up to 1) result in blue. In order to get black sea and white clouds the color hue is neutral for very small (close to 0 and below) and very large (close to 1 and above) amplitudes.

5 bit Brightness + 3 bit Color*

Color bitmaps with 8 bit resolution. The 5 MSBs (32 steps) are used for brightness information (luminance), the 3 LSBs are used for color hue. The hue results from Hue=2*(Channel2+Offset2)*Amplify2. For the 8 colors the color circle is passed twice.

4 bit Brightness + 4 bit Color

Color bitmaps with 8 bit resolution. The 4 MSBs (16 steps) are used for brightness information (luminance), the 4 LSBs are used for color hue.

The picture geometry can be compressed or expanded in the vertical direction by omitting or repeating received lines. An y step of 0.5 stretches the picture to double height, while a value of 2 compresses it to half height. IOC is equally influenced.

The final number of pixels in each image line can be defined, but proper vertical compression might be required in order to maintain the final picture aspect. For example, if a transmission is intended for 1810 pixels/line, thus having an IOC of 576, if the picture should have only 1024 pixels/line, the y step should be set to 1.77 in order to preserve the value of IOC.

As satellites may fly from South to North or from North to South, the direction of the image is also defineable. In N-S images, the newly decoded lines will always be placed at the bottom end of the already received ones. In S-N images, the new lines will be inserted at the top of the already received image.

WiNRADiO Advanced Digital Suite User’s Guide

Digital Header Processing

To be able to extract digital header information from the received data, some special parameters are required: The position in the line at which the digital data starts and the length of this section are required to extract the header text. The characters can be coded using ASCII or EBCDIC alphabets.

The digital header information may be replicated in more image lines to ensure reliable retrieval. The total number of lines in pictures with a digital header is limited, usually at 800. When the number of lines in the decoded picture reaches this limit, the receiving ends.

If enabled, the data in the digital header can be used to generate the name of the bitmap file which will be used to save the received image as soon as it is complete. In the character order field there can be any number of commaseparated numbers that define the order in which the header characters are to be used to construct the file name.

For example, with the decoded WEFAX header shown below, if the defined character order is 21, 22, 23, 15, 16, 17, 18, 19, then the resulting bitmap image file would be C0204230.bmp.

WiNRADiO Advanced Digital Suite User’s Guide

Signal Study

This section of the Decoder interface allows input signal analysis both in time and frequency domains, while providing several decoder settings that can be more easily set when aided by the realtime signal display.The input signal can be amplified by the value specified below the oscilloscope display. If the input signal is close to the range limit and the clipping indicator starts becoming active, the amplify value must be reduced. For weak signals, amplification will provide better quality signal for the decoding engine. Normally, the signal should be amplified as much as possible, but still below the clipping level.

Image Study

While receiving an image, there are up to four image statistics displayed, depending on the overall decoder settings. These statistics show the distribution of different parameters of the received image.

If both virtual channels are active, demodulated data histograms are displayed for both of them. Otherwise, such information is displayed only for the first one.

Luminance distribution is also always present, but the chrominance histogram is available only for color modes.

WiNRADiO Advanced Digital Suite User’s Guide

Task Scheduler

The Task Scheduler provides a facility to tune the receiver to a user defined frequency at a userdefined time and decode and store incoming images fully autonomously. Every defined task can have both the start and stop times specified. Audio input samples can be recorded to a separate WAV file (independent of the input/output W AV file), and the decoded data can be sent to a separate image file, also independently of the main log file.

There are three main task types:

• Continuous - The task is active all the time. At the start, the receiver is correctly tuned and the demodulator is set. This is useful when fax transmissions are available only on a specific frequency and it is desirable to automatically tune to this frequency each time the decoder is started.

• Periodical - The task is activated at a specified time of day, at any specified day of the week. When the specified condition becomes true, the receiver and the decoder are set according to the user-specified settings.

• One time - The task is executed only once, when the date and time conditions are met.

The receiver frequency, sensitivity, volume and mode values must be set first. These values should be manually tuned and tested and only then used for a scheduled task.

The file names defined in the task scheduler can include “wildcard” specifiers to generate distinct file names automatically, and so avoid overwriting of the same file:

1) %d - Current date - will be replaced with a string formated as dd mm yyyy based on the date on which the recording is started.

2) %t - Current time - will be replaced with a string formated as hh.mm.ss based on the time at which the recording is started.

3) %0 ... %9 - Current index - will be replaced with an automatically incremented value. The number following % defines the number of digits in this field. The leading spaces will be padded with zeros.

4) %% - Use this sequence if you wish to include the % character in the file name.

WiNRADiO Advanced Digital Suite User’s Guide

Advanced NAVTEX Decoder

NAVTEX (NA V igational telEX) is a system for broadcast and automatic reception of maritime safety information by means of a narrow-band direct-printing telegraphy. It provides shipping with navigational and meteorological warnings and urgent information through automatic printouts from a dedicated receiver.

The NA VTEX service is available worldwide on 518kHz and has a simple humanreadable message format. The characters are transmitted at 100bits/second using a 7-bit alphabet, coded according to the CCIR476-5 standard (this is also known as SITOR-B protocol).

This decoder is designed to work either with a DSP based WiNRADiO receiver, or a non-DSP WiNRADiO receiver with the assistance of a sound card. If the DSP is present and the receiver is controlled by the WiNRADIO WR3000-Series receiver virtual panel, the decoder will take advantage of it, otherwise it will fallback to the sound card. For each of these two situations there is a different user interface in the setup section, due to additional settings required by the sound card. (For more information on these settings, refer to page 10).

The NAVTEX transmissions are continuous, messages being sent several times with time intervals between them, in order to provide redundancy in case of poor reception conditions. This decoder displays all received data, even if a particular message has already been received earlier, because there might be erroneous characters in any of the received instances of a message. The CCIR476-5 standard provides for detection of odd numbers of errors in a character, with no error correction or checking at a message level.

All the received data can be appended to a log file. The name of the log file can be changed anytime and the decoder will immediately start using the new name. Any errors occuring while opening the log file are ignored and the decoder continues receiving. This main log file is independent of the secondary log files that can be specified in the Task Scheduler.

WiNRADiO Advanced Digital Suite User’s Guide

Decoder Setup

The Advanced NA VTEX Decoder automatically detects the W iNRADiO receiver type. This determines what you will see at the top of the main control panel. Models without a built-in DSP will need to use a sound card for the software to function, for which purpose the control panel will contain the “wave device” setup.

As a computer may have several wave devices installed (for example, one sound card and a modem with voice capabilities), the user has to select the sound card as the desired wave device. The Wave-in device in use drop-down list shows all the installed wave devices. “Windows default” is the Control Panel setting specified under Start | Settings | Control Panel | Sounds and Multimedia | Properties | Audio.

WiNRADiO Advanced Digital Suite User’s Guide

If a sound card is specified in the Control Panel for both playback and recording (likely, but not always necessarily so), then you can simply select Windows Default as the wave device for the demodulator. Otherwise, the specific name of the sound card should be selected.

The next parameter to select is the mixer device associated with the already selected sound card, using the Mixer device in use drop-down list.

If the signal is arriving to the sound card via an external cable, the cable should be connected to the Line input of the sound card. This input must also be selected in the Mixer Line in use drop-down list and also in the Recording Control of the mixer control panel. To get to the Recording Control, you need to select Options | Properties | Recording in the top bar menu of the Volume Control panel (which is actually Playback Control). The signal level at the decoder input can be observed in the Audio level window while manually adjusting the volume. For optimal decoding the signal level should be somewhere between 60% and 70% of the full scale. When the signal peaks turn red, this indicates that the level is too high and distortions (causing decoding errors) may result.

The remaining controls are common to all WiNRADiO receiver types:

Bar button displays the spectrum using vertical bars instead of the standard oscilloscope-type trace. This display mode makes the spectrum peaks and valleys sometimes easier to observe.

Linear FFT display provides better results when searching for the mark and space tones, but the spectrum outside the region of interest is barely observable. Linear gain should be applied for amplification as the displayed values would be otherwise too small; the usual suitable amplification values are around 200. Most of the time only the two mark/space tones will be observable in this mode.

The waterfall display in the tones estimator group is sometimes easier to observe if the colors are inverted (high levels become darker). Color inverting is not affecting the displayed data and will not cause any loss of information.

WiNRADiO Advanced Digital Suite User’s Guide

The Decoder Setup also contains the mark and space tones estimator with an FFT spectrum display. Mark and space tones are the most significant spectrum components. They must both fall between 500Hz and 2800Hz (this is achieved by fine tuning of the receiver), with a maximum shift of 1300Hz. These limits have been set in order to enjoy maximum decoding quality. Good tones estimation is obtained if the FFT results are averaged. The average level specifies the “weight” of a new set of FFT results in the exponential averaging algorithm; a value of around or under 0.20 provides usually the best results. The examples above demonstrate that linear displays generally provide more accurate results.

A manual mark/space tones setting is also available. In the manual mode, the desired frequency shift can be specified. Nowadays most transmissions use 170Hz frequency shift. In addition, 425Hz and 850Hz shifts are available for older transmitters, and an “any” mode exists for non-standard transmissions. Dragging one of the two cursors when a specific frequency shift is selected moves the other cursor accordingly.

The values provided by the tones estimator, either automatically or manually , are also shown in the AFSK tones panel in the main decoder window. Here they are used for further processing or just for reference. If the Use estimated button is activated, these values are also copied to the two mark/space frequency edit boxes. Otherwise, values manually entered into these two edit boxes will be used for the demodulation.

WiNRADiO Advanced Digital Suite User’s Guide

WAV File Processing and Recording

The WiNRADiO receiver audio output can be recorded in a W indows PCM WA V file format (mono, 16bits, 11025Hz sampling rate), or you can playback an already existing WAV file as follows:

• Firstly, the file location has to be selected. The standard Windows Open File dialog box opens when the (…) button is pressed. After selection, the file name will appear in the Input/Output W AV window . You can type the file name directly into this window. If the opened file contains a recorded signal, its format will be automatically verified.

Start recording. As long as this button is pressed, the signal samples are added to the file, and the time elapsed from the beginning of the record is displayed in the hours-minutes-seconds format.

Start playback. The time elapsed from the beginning of the record, and also the total length of the record are displayed in the hours-minutes-seconds format.

Pause recording or playback. Stop recording or playback.

Jump in steps towards the beginning or to the end of a recording. In record mode, the signal samples will be overwritten.

Walk through a recording using the progress track bar. In record mode, the signal samples will be overwritten.

An already opened WAV file will be automatically closed when a new one is opened or when the application ends.

WiNRADiO Advanced Digital Suite User’s Guide

NAVTEX Task Scheduler

The Scheduler provides a facility to tune the receiver to a user defined frequency at a user-defined time and decode and store incoming NAVTEX broadcasts fully autonomously . Every defined task can have both the start and stop times specified. Audio input samples can be recorded to a separate WAV file (independent of the input/output WAV file), and the decoded data can be sent to a separate log file, also independently of the main log file.

There are three main task types:

• Continuous - The task is active all the time. At the start, the receiver is correctly tuned and the demodulator is set. This is useful when NAVTEX transmissions are available only on a specific frequency, for example the world-wide used 518kHz, and it is desirable to automatically tune to this frequency each time the decoder is started.

• One time - The task is executed only once, when the date and time conditions are met.

The receiver frequency, sensitivity, volume and mode values must be set first. These values should be manually tuned and tested and only then used for a scheduled task. For mark and space frequencies the best choice is to use automatically estimated values as there might be small frequency fading effects in a real transmission. The best results are usually obtained if the estimator is set to the automatic mode and the averaging level is quite low (below 0.20).

WiNRADiO Advanced Digital Suite User’s Guide

The file names defined in the task scheduler can include “wildcard” specifiers to generate distinct file names automatically, and so avoid overwriting of the same file:

1) %d - Current date - will be replaced with a string formated as dd mmm yyyy based on the date on which the recording is started.

2) %t - Current time - will be replaced with a string formated as hh.mm.ss based on the time at which the recording is started.

4) %% - Use this sequence if you wish to include the % character in the file name.

WiNRADiO Advanced Digital Suite User’s Guide

Advanced Packet Radio Decoder

Packet Radio is the common name for a radio amateur digital network that uses a variant of the X.25 protocol, known as AX.25 (from Amateur X.25). The data to be transmitted is packed into HDLC (High Level Data Link Control) frames, passed through a special modulator and sent on air.

This decoder is designed to decode Radio Packet transmissions at bit rates of 300, 1200 and 2400 bits/ second. While the first two are very common, for 2400 bit/ second an over-clocked 1200 bits/second modem is typically used, in two variants:

• TCM3105 modem chip with 8MHz clock, giving 3970 Hz and 2165 Hz for mark and space tones;

• TCM3105 modem chip with 7.3728Mhz clock, giving 3658 Hz and 1996 Hz for mark and space tones.

This decoder is designed to work either with a DSP based WiNRADiO receiver, or a non-DSP WiNRADiO receiver with the assistance of a sound card. If the DSP is present and the receiver is controlled by the WR-3xxx virtual panel, the decoder will take advantage of it, otherwise it will fall-back to the sound card. For each of the two situations there is a different user interface due to the additional settings required by the sound card. Refer to page 10 for more information.

The packet radio transmission is done in bursts ranging from a simple 15 bytes frame to many information frames that can hold several thousands of bytes, for several destinations, when the transmitter is a highly used network node. The transmission starts with a preamble containing alternating 0s and 1s for the receiver NRZI demodulator synchronization, but a slow squelch may not have enough time to detect the transmission. For this reason, the receiver squelch should be disabled to ensure that even the first frame in a sequence is correctly received.

WiNRADiO Advanced Digital Suite User’s Guide

Decoder Setup

Advanced Packet Radio Decoder automatically detects the WiNRADiO receiver type. This determines what you will see at the top of the main control panel. Models without a built-in DSP will need to use a sound card for the software to function, for which purpose the control panel will contain the “wave device” setup.

No set-up is necessary for DSP-based WiNRADiO receivers. For non-DSP receivers, use the installation information on page 10-15.

The remaining controls are common to all WiNRADiO receiver types:

• The decoded messages are displayed in the panel main window and at the same time can be written into a text file if the Log file button is pressed. The file name has to be manually typed or selected using the standard Windows Open file dialog, which is opened by clicking on the “three dots” button. The saved messages are accompanied by their corresponding time and date, in the preferred Log date format.

• Under poor receiving conditions, select the CRC Ignore button to allow displaying of frames with incorrect control checksums, but with a correct header format. Erroneously received messages have their header displayed in red color.

• The correct bit rate must be specified by selecting one of the four available buttons. In the spectrum display shown at the left of the speed buttons, the range in which the AFSK signal should be received is displayed in grey. As 1200 and 2400 bits/second are used only in VHF and UHF, the tones will always be in the correct range as long as the receiver is properly tuned. Wrong tuning would cause only poor receiving quality. For 300 bits/second packet radio transmissions (on HF using SSB modulation), the receiver should be carefully tuned for the AFSK tones to fall in the highlighted range.

WiNRADiO Advanced Digital Suite User’s Guide

Advanced Signal Classifier

The Advanced Signal Classifier is useful for conditional scanning, based on transmission content type. Using sophisticated signal processing algorithms, the program determines, with a certain probability level, which of the following content types is predominant in the received demodulated signal:

Silent channel

The audio signal energy level at the receiver output is below the energy thr eshold

- normally encountered in speech pauses and on unoccupied frequency channels while in AM, USB, LSB and CW modes.

Noise

The transmission is very noisy or the receiver is tuned to an unoccupied channel in an FM mode. The decision is made using the ratio between the signal energy and the maximum correlation level.

Single tone

The demodulated signal is a single, continuous tone, with an energy level above the tone threshold - can be reported also on very slow CW transmissions.

Two-tone AFSK

The signal appears to be a data transmission that uses two-tone AFSK modulation; the difference between the energy levels of the two tones must be below the AFSK threshold and both of them must be above the tone threshold.

Data transmission

This type of signal has fast transitions around a DC offset, with periods between them corresponding to an integer number of bit periods.

Voice or other

This is the default signal type, which the Classifier falls back to, for all unclassified signals.

The Advanced Signal Classifier is designed to work either with a DSP based WiNRADiO receiver, or a non-DSP WiNRADiO receiver with the assistance of a sound card. If the DSP is present and the receiver is controlled by the WiNRADIO WR-3000-Series receiver virtual panel, the plug-in will take advantage of it, otherwise it will fall-back to the sound card. For each of these two situations there is a different user interface, with additional settings required by the sound card.

WiNRADiO Advanced Digital Suite User’s Guide

While running, the Classifier lights-up the indicator that corresponds to the currently detected audio signal type. Only one indicator is active at a time.

If the receiver is in the scanning mode and the currently detected audio type matches one of the selected types, a scanning resume command is sent to the receiver application. This ensures that the scanning will not be interrupted by a transmission of no interest.

If the Classifier settings are modified and the program refuses to work correctly, the Restore defaults button can be used to return to default settings.

WiNRADiO Advanced Digital Suite User’s Guide

Advanced Signal Conditioner

The Advanced Signal Conditioner employs various digital filtering techniques designed to process and improve the readability of demodulated signals:

• Lowpass, highpass, bandpass or bandstop filtering

• Signal display in time or frequency domains

• Signal frequency identification by tone marking

• Adaptive noise reduction

• Adaptive reduction of single or multiple tone interference

• Pitch shifting • Signal level control

• Speech inversion • Configuration saving and retrieving

• Recording of a processed signal • Processing of a recorded signal The Conditioner automatically detects the WiNRADiO receiver type it is working

with. Models with built-in DSP should be used for best quality and the control panel will look like the one shown below, otherwise a sound card is required for the software to function.

WiNRADiO Advanced Digital Suite User’s Guide

For sound card use, there are additional options that allow the user to select the audio device with its associated mixer, and to specify which input is physically connected to the WiNRADiO receiver . For more details refer to page 10.

From the signal processing point of view, the different modules of the Advanced Signal Conditioner can be interconnected in various userselectable ways, depending on the type of processing required, as shown in the block diagram above. The input signal, obtained either from the WiNRADiO receiver or from the computer hard disk, may be routed “straight through” to the PC speaker output or also to the hard disk, if no signal processing is desired. On the other hand, in the extreme case, all signal processing modules may be included in the signal path.

The Advanced Signal Conditioner is very CPU resource intensive, especially the sound card version. The CPU usage display provides an indication of the CPU load when changing the different processing parameters. It is recommended not to exceed 80% of the CPU resources, otherwise the computer may considerably slow down or even “freeze”.

WiNRADiO Advanced Digital Suite User’s Guide

Lowpass, Highpass, Bandpass or Bandstop filtering

The lowpass, highpass, bandpass or bandstop filters included in the Advanced Signal Conditioner are linear phase filters of the FIR (Finite Impulse Response) type. These filters can be applied to voice, data and CW (Morse) signals to improve their signal-to-noise ratio by removing the high and/or low frequency components that do not contribute significantly to the carried information. The steep skirt of each filter can also be used for adjacent channel interference elimination in crowded short wave bands.

In the filter schematic below, the h filter coefficients are calculated according to the selected filter type and its frequency domain parameters using the windowed-sinc method, and the w samples correspond to a Blackman window. The filter Length (the number of taps) has to be an odd number and can be set by the user to between 3 and 1001 (the CPU speed is the limiting factor), if the software relies on a soundcard. For WiNRADiO receivers with DSP facilities, the filter Length is set to a fixed value of 221.

After selecting an appropriate Filter type, the user can define the value of the characteristic filter parameters, such as the low and high (–6dB) frequency limits, central passband frequency, passband width and filter length (if used with a soundcard). Their values can be typed directly in the appropriate edit windows labeled Low, High, Centre, Width and Length, or can be increased or decreased using the spin buttons. Alternatively, the frequency parameters can be modified graphically, by dragging the vertical lines (representing the boundaries between the stopband and the passband) and the top horizontal line (representing the passband/stopband position) of the displayed filter shape. The Centre frequency is always equal to (Low +High)/2, and the passband Width is equal to High-Low . The software automatically calculates and updates new filter coefficient values.

WiNRADiO Advanced Digital Suite User’s Guide67WiNRADiO Advanced Digital Suite User’s Guide

When a filter is active, the real-time signal spectrum display shows two frequency characteristics. The straight red lines represent the ideal characteristics, while the actual characteristics are drawn in cyan color. (The irregular ripples present in the stop-band region of the actual frequency response are caused by the 16bit fixed point calculations round-off effects.)

The signal spectrum can be viewed either at the filter input or at the filter output. In order to display the signal spectrum at the filter input, the user needs to click the left mouse button outside the filter pass-band, as shown below. If clicked inside the filter pass-band, the display shows the signal spectrum of the filtered signal.

WiNRADiO Advanced Digital Suite User’s Guide

Signal display in time and frequency domains

To assist the user in selecting optimum fixed filter characteristics, and to view the effects of the noise reduction and tone rejection algorithms, the Advanced Signal Conditioner contains its own oscilloscope and spectrum analyzer facility.

The screen shots below demonstrate the various commands available. The display is controlled using a dedicated pop-up menu opened with a right-click on the display window .

There are three Signal sources to select from: None (the display is not active), signal Input, or signal Output.

The way in which the signal is displayed depends on the selected Mode. The Oscilloscope option exists for time domain observations, and the Analyser option for frequency domain ones. The time and frequency ranges depend on the sampling frequency used. With a sound card, the input signal is sampled with a frequency of 11,025Hz. With the DSP, 8,000Hz is used.

If the Oscilloscope mode is selected, the displayed waveform depends on the selected Trigger mode. In the Free run mode, the signal is displayed continuously . The Level option synchronizes the beginning of the displayed waveform with a fixed (reference) level (the software will wait for a sample with the specified value to appear). If the signal never reaches that level, there will be nothing to display. The waveform can cross the reference level in any direction. However, if either the Positive or Negative option is selected, the reference level will have to be crossed up or down, respectively.

WiNRADiO Advanced Digital Suite User’s Guide

The reference level for the Level, Positive or Negative triggering modes can be manually adjusted. In order to change its value, place the cursor over the little red triangle on the left side of the oscilloscope window. The cursor will change its shape to a double arrow, as shown below. Then press the left mouse button and drag the triangle upwards or downwards.

There are also several types of Trace types to select from: Line, Points or Bar.

WiNRADiO Advanced Digital Suite User’s Guide

The Marker Tone

A marker tone can be introduced at the input or at the output of the signal processing chain, when either the Input or Output buttons under the Marker tone is activated. The Off button disables this facility.

The marker tone is useful with fixed narrow band filtering of an incoming signal, such as in CW reception, and the listener wishes to adjust the frequency to a value comfortable for listening. To be able to see the marker tone as shown above, the time and frequency display needs to be in the Signal source = Output mode. If the Input button is pressed, the marker tone facility can be useful for testing the effectiveness of fixed filters, adaptive noise reduction and tone rejection functions.

There are two parameters of the marker tone which can be manually changed: its frequency and level. The frequency can be varied between 0Hz and half the sampling rate, and the tone level can have any value between –100dB and –3dB relative to the maximum signal level.

WiNRADiO Advanced Digital Suite User’s Guide

Noise reduction

In practical situations, especially on HF bands, the received audio waveforms contain noise components. Depending on the amount and type of noise, the quality of the received signals can range from being slightly degraded, annoying to listen to, or totally unintelligible in the extreme case.

The noise suppression facility of the Advanced Signal Conditioner is based on least mean-square (LMS) adaptive filtering. This type of filtering, implemented according to the block diagram below, has the benefit of requiring no prior knowledge of the characteristics of both the useful signal and noise. The method takes advantage of quasi-periodic nature of speech and CW signals. Offering only slight degradation for speech signal, the amount of noise reduction is influenced by the correlation characteristics of noise, and typically ranges from 3dB to 20dB.

This adaptive filter is a combination of a FIR (Finite Impulse Response) filter with “Length” number of taps (Length=M in the diagram above), and a delay line with “Delay” number of taps (Delay=N in the diagram above). With a DSP, these parameters have fixed values, namely Length=128 and Delay=8. With the sound card, the Length value needs to be determined according to the CPU speed (the higher, the better), while the Delay value should be kept around 8.

The values of the FIR taps coefficients h are permanently updated using a “leaky” LMS algorithm, taking into account an error signal and the energy of the input signal samples present in the filter’s cells, according to the relationship below. The Adaptation constant in the Noise reduction group is x, the Leakage coefficient is µ (µ<1), and the Energy offset is r. With a DSP, the Energy offset has a zero value, but with a sound card a small positive value is used to ensure that the update term does not become excessively large when the signal energy temporarily becomes small.

WiNRADiO Advanced Digital Suite User’s Guide

The adaptive filter is activated using the Noise reduction button under the Filter type heading. Noise reduction can work simultaneously with fixed filtering and tone rejection. The screen shots below demonstrate this program’s capabilities: Noise reduction is combined with a fixed Bandpass filter.

The resulting signal-to-noise ratio can be maximized by fine tuning of the Noise reduction parameters.

WiNRADiO Advanced Digital Suite User’s Guide

Tone Interference Rejection

In-band single tone or multiple tone interference is commonplace, in particular on HF bands. An effective method of rejecting this type of interference, so called

auto notch, is based upon the principles of least mean-square (LMS) adaptive filtering. The notch frequency is equal to the interfering tone frequency. This

filtering is implemented according to the block diagram below and has the benefit of requiring no prior knowledge of the interfering tone frequency.

This adaptive filter is a combination of a FIR (Finite Impulse Response) filter with “Length” number of taps (Length=M in the diagram above), and a delay line with “Delay” number of taps (Delay=N in the diagram above). With a DSP, these parameters have fixed values, namely Length=62 and Delay=48. With a sound card the Length value needs to be determined according to the CPU speed (the higher, the better), while the Delay value should be kept around 48.

The values of the FIR taps coefficients h are permanently updated using “leaky” LMS algorithm, taking into account an error signal and the energy of the input signal samples present in the filter’s cells, according to the equation below. The Adaptation constant in the Auto notch group is x, the Leakage coefficient is µ

(µ<1), and the Energy offset is r. With a DSP, the Energy offset has a null value, but with a sound card it has a small positive value to ensure that the update term does not become excessively large when the signal energy temporarily becomes small.

WiNRADiO Advanced Digital Suite User’s Guide

Tone rejection is activated when the button Auto notch under the Filter type heading is pressed. Auto notch can work simultaneously with fixed filtering and noise rejection. The screen shots below demonstrate the program’s capabilities: Auto notch is combined with a fixed Bandpass filter.

Almost complete tone rejection can be obtained by trial and error, by finely tuning the Auto Notch parameters.

Note that the Auto Notch function should not be activated while receiving useful CW signals. Instead, a bandpass filter with as small passband width as possible should be used.

WiNRADiO Advanced Digital Suite User’s Guide

Pitch shifting

Although WiNRADiO receivers have very fine tuning steps, the Advanced Signal Conditioner offers an additional fine tuning mechanism. This pitch (frequency) shifting function is based on an algorithm shown below which uses the Hilbert transformer to provide an almost perfect shift of a band of frequencies so that a constant group delay is maintained throughout the whole band.

In order for Pitch shifting to be useful for improving CW or SSB signal clarity, the range of the frequency Shift is –500Hz to +500Hz. The Length (number of taps) of the Hilbert transformer is fixed to 63 for DSP use, but user selectable (the greater the better) when used with a sound card, according to the available CPU resources.

As shown in the screen shots below, the pitch shifter is active when the button On under the Pitch shifter heading is pressed.

In the following example, an up-shift of 500Hz is applied to the output signal frequency spectrum (that’s why there is no energy shown in the range from 0Hz to 500Hz). The next example shows the spectrum down-shifted by 354Hz.

WiNRADiO Advanced Digital Suite User’s Guide

Output signal level control

The processed signal level at the Advanced Signal Conditioner output can be changed either manually or automatically, depending on which of the Gain buttons is activated.

When using the fixed gain of 6dB or 12dB, special care needs to be taken that no distortions occur, caused by an output signal overflow. The probability of an overflow is reduced if AGC (Automatic Gain Control) is used.

If Automatic Gain Control is selected, the signal level will be maintained at 0dB using a “feed-forward” algorithm.

WiNRADiO Advanced Digital Suite User’s Guide

Speech inversion

The speech inversion algorithm is used for descrambling of speech-inverted transmissions. The original signal is passed through an input low-pass filter, then mixed with the desired inversion frequency and finally fed via an output lowpass filter.

Both input and output low-pass filters have a cut-off frequency equal to the inversion frequency. The input filter removes all spectrum components above the inversion frequency (so that they do not appear in the desired range through the aliasing effect). The output filter removes the mixing products above the inversion frequency.

This algorithm gets more complex when the inversion frequency is higher than a quarter of the sampling rate: After mixing the signal with the virtual local oscillator, there will be spectrum components up to twice the inversion frequency , which means that there will be components over the Nyquist frequency that will distort the result through aliasing. To prevent this, the input signal sampling rate will be doubled for the spectrum inversion and changed back to normal at the end. This applies for the sound card operation where the execution time is quite important. The DSP operation uses this algorithm always.

For the sound card operation there are two settings: the frequency used for spectrum inversion and the filters length (which should be set as high as the CPU resources permit). The DSP version uses only the first parameter.

This feature is not available in the US version of the Advanced Digital Suite due to legislation restrictions (1986 Electronic Communications Privacy Act).

WiNRADiO Advanced Digital Suite User’s Guide

Configuration saving and retrieving

All the currently active settings of the Advanced Signal Conditioner can be given a name and can be saved for later re-use.

The name has to be typed in the New settings name window, which becomes visible immediately after pressing the Add button under the Settings heading, as shown below. The settings are then added to the list by pressing the Ok button of the New settings name window. The configuration may be updated later by pressing the button Modify.

If a new setting is selected from the list as shown below, the configuration associated with that name becomes active.

If a particular configuration is no longer needed, it can be deleted from the list by clicking the Remove button.

Recording a processed signal

The output signal of the Advanced Signal Conditioner can be recorded in a Windows PCM WAV file format (mono, 16bits, 11025Hz sampling rate), by following these steps:

Firstly, the file name and its location have to be specified. The standard

Windows Open File dialog box opens when the button marked with three dots (…) is pressed. The file name will appear in the Output WAV edit box. You can also type the file name directly into this window. If the opened file already contains a recorded signal, the program will verify its format and if it is the same, the new signal samples will be appended to the end of the opened file.

To start recording, press the button marked with a red circle. As long as this button is pressed, the processed

signal samples will be added to the file, and the time elapsed from the beginning of the record will be displayed in the hours-minutes-seconds format.

WiNRADiO Advanced Digital Suite User’s Guide

To stop recording, press the button marked with a red square. The recording can be restarted later, by pressing again the red circle button.

If the contents of a recorded file are no longer useful, the file can be overwritten from the start upon pressing the button marked with a green double arrow.

Processing of a recorded signal

The input of the Advanced Signal Conditioner can be a real-time received signal or an already recorded one. The recorded signal has to be in a Windows PCM WAV file format: mono, 16bits, 11025Hz sampling rate.

A recorded signal is processed in the same way as a real-time one, but there is a great advantage in using a recorded signal, in that it can be processed again and again with different processing options.

To use a recorded signal for processing by the Advanced Signal Conditioner, follow these steps:

Firstly, the file name and its location have to be specified. The standard Windows Open File dialog box opens

when the button marked with three points (…) is pressed. The file name will appear in the Input WAV edit box. You can also type the file name directly into this window.

Start playing the WAV file. The time elapsed from the beginning of the record, and the total length of the record are displayed in the hours- minutes-seconds format.

When the processing parameters have to be changed, it is better to pause the player.

WiNRADiO Advanced Digital Suite User’s Guide

To stop the player, press the button marked with a green square.

To jump to the beginning or to the end of the recording, press the buttons marked with double arrows.

WiNRADiO Advanced Digital Suite User’s Guide

Advanced Squelch Controlled Recorder

The Advanced Squelch Controlled Recorder offers functionality beyond that normally available with conventional sound recorders. The recording can be conditional upon the signal level, depending on the receiver squelch level setting. The playback function includes pitch-shifting, speed control and a descrambler for speech inversion.

The program automatically detects the WiNRADiO receiver type. Models with built-in DSP should be used for best quality, otherwise a sound card is required for the software to function.

No set-up is necessary for DSP-based WiNRADiO receivers. For non-DSP receivers, use the installation information on page 10-15.

WiNRADiO Advanced Digital Suite User’s Guide

Supported Audio Formats

All audio formats supported by the Advanced Squelch Controlled Recorder can be defined by the following three parameters:

Compression type

Defines the exact format of the samples. Possible values are:

PCM Linear

The default format. It does not provide any compression at all, the samples are identical to those sent to or received from the recording/playback device (i.e. sound card or DSP). The samples can have 8 or 16 bits. The 8-bit PCM linear

format provides the lowest quality of all the supported audio formats.

PCM A-law

A simple compression that replaces each 16-bit audio sample with an 8-bit value based on a simple algorithm. It has the advantage of keeping much of the original signal dynamic range using a logarithm-like compression. The encoding rule is different for small value samples - the compression is linear.

PCM u-law

A compression similar to A-law, but with no special encoding rule for small value samples.

Bits per sample

Specifies the size of the audio samples. Possible values are 8 and 16, but selectable only when the compression type is PCM linear. For all other compression types, the audio samples are always 16-bits wide.

Samples per second

Specifies the number of audio samples to be processed in one second (sampling rate). Possible values are 8000, 11025, 16000, 22050 and 44100 when working

with a sound card. If the on-board DSP is used, only 8000, 11025 and 16000 samples per second can be processed.

The audio format can be set by the user only when a new audio file is created. For already existing audio files, the format specification embedded in the file will be used instead and the corresponding interface controls will be disabled.

The audio format cannot be changed while in record or playback mode, not even for a newly created file.

WiNRADiO Advanced Digital Suite User’s Guide

Audio Processing Tools

The squelch controlled recorder supports the following audio processing functions:

Pitch shifting

Provides audio spectrum shifting by the specified frequency shift size. If the shift size is positive, the spectrum is translated to higher frequencies. A range of the original audio spectrum will be lost by pitch shifting: For positive shift it will be at higher frequencies and for negative shift at lower frequencies. The width of the lost spectrum range equals to the size of the shift.

Variable playback speed

Can be used to change the speech rate while preserving the speaker characteristics. There are three possible playback speeds:

50% (half)

The speech rate is reduced to half by inserting extra audio samples.

100% (normal)

The speech rate is not affected, the played audio samples will be exactly the same as in the audio file.

200% (double)

The speech rate is doubled by removing audio samples from the original file.

Speech inversion

Done by reversing the original audio spectrum. This is done by mixing the original signal with a tone of the specified frequency and passing the result through a low-pass filter. Depending on the relationship between the samples per second and the speech inversion frequency, the process can be more complex as all mixing and filtering must be done at a sampling rate equal to twice the number of samples per second.

This feature is not available in the US version of the Advanced Digital Suite due to legislation restrictions (1986 Electronic Communications Privacy Act).

All these tools can be used in any possible combination, being completely independent. They do not affect the original audio file.

WiNRADiO Advanced Digital Suite User’s Guide

Handling the Audio File

Irrespective of the wave device selected, the recorder panel contains a waveform playback control, with familar functions.

Specify the sound file name and its location. The standard Open File dialog box opens when the button marked with three dots (…) is pressed. After selection, the file name will appear in the edit window. Alternatively, type the file name directly into this window. The decoder automatically verifies the correct format of the wave file.

Start recording. As long as this button is pressed, the signal samples are added to the file, and the time elapsed from the beginning of the record is displayed in the hours-minutes-seconds

format.

Start playing the WAV file. The time elapsed from the beginning of the recording and also the total length of the recording are displayed in the hours-minutes-seconds format.

T o temporarily pause the playback or recording, press this button. The paused operation can be continued by pressing the button once again. While paused, the cursor that indicates the position

in the audio file can be manually moved. T o step forward or backward, use the two respective

buttons marked with double arrows.

To walk through the record, use this progressive track bar.

To stop the player, press the button marked with a green square.

WiNRADiO Advanced Digital Suite User’s Guide

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WiNRADiO Advanced Digital Suite User’s Guide

Index

Advanced ACARS Decoder 33 Advanced Audio Recorder 8 Advanced Audio Scope and Spectrum Analyzer 7 Advanced Audio Signalling Decoder 37 Advanced Fax Decoder 41 Advanced NAVTEX Decoder 52 Advanced Packet Radio Decoder 59 Advanced Signal Classifier 7, 61 Advanced Signal Conditioner 8, 63 Advanced Squelch Controlled Recorder 81 Alarms Configuration 39 Alpha T ags Configuration 40 Audio ACARS Signal Playback 36 Audio Processing Tools 83 Audio Scope 18 Audio Scope and Spectrum Analyzer 16 Audio Signalling Decoder and Logger 8

Baseline clipper 25, 32

d/dt button 19 Decoder Setup 34, 53, 60 Decoding Engine Setup 43 Demodulator Selection 44 Digital Header Processing 49

Filtering 65 Frequency markers 25 FTT (Fourier Transform) Window 26

Grid button 18, 23

Hardware Installation 9 Horizontal Synchronisation 46

Image Constructing Rules 47 Image Study 50 Installation 9 Introduction 7

Line Processing Regions 47 Linear spectrum display 24, 29

Marker Tone 70 Memory function 21

NAVTEX Decoder 7, 52 NAVTEX Task Scheduler 57 Noise reduction 71

Output signal level control 76

WiNRADiO Advanced Digital Suite User’s Guide

Packet Radio 59 Pause 22, 25 PCM A-law 82 PCM Linear 82 PCM u-law 82 Pitch shifting 75, 83

Received Image 42 Recorder and Player 17 Recording a processed signal 78 Reference Clock Extraction 44

Samples per second 82 Setting up the Scope and Spectrum Analyzer 16 Signal display in time and frequency domains 68

WiNRADiO Advanced Digital Suite User’s Guide

Signal Study 50 Software Installation 9 Spectrum Analyzer 23 Speech inversion 77, 83 Supported Audio Formats 82 Sweep range 25, 31 System Requirements 9

Task Scheduler 51 Time markers 20, 32 Timebase 19 Tone Interference Rejection 73 Trace Type 18 Trigger 19, 24

Using The WiNRADiO Advanced Digital Suite 10

Variable playback speed 83 Vertical scale 21

Waterfall Spectrum Analyzer 28 Waterfall spectrum display types 29 WAV File Processing and Recording 56 WEFAX and HF Fax Decoder 7

Winradio Advanced Digital Suite instruction manual

Specifications and Main Features

Frequently Asked Questions

User Manual