Clear-Com PTX-3 User Manual
CLEAR-COM WIRELESS IFB
PTX-3
UHF DIGITAL HYBRID IFB TRANSMITTER
INSTRUCTION MANUAL
PTX-3 UHF Digital Hybrid IFB Transmitter Instruction Manual
© 2008 Vitec Group Communications Ltd. All rights reserved.
Part Number 810401Z Rev. 2
Vitec Group Communications LLC
850 Marina Village Parkway
Alameda, CA 94501
U.S.A
Vitec Group Communications Ltd
7400 Beach Drive
IQ Cambridge
Cambridgeshire
United Kingdom
CB25 9TP
Vitec Group Communications
Room 1806, Hua Bin Building
No. 8 Yong An Dong Li
Jian Guo Men Wai Ave
Chao Yang District
Beijing, P.R. China 100022
® Clear-Com, CellCom/FreeSpeak and the Clear-Com Communication Systems logo are registered trademarks of The Vitec Group plc.
CONTENTS
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
Digital Hybrid Technology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
Audio Input Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
Input Limiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
DSP Compatibility Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
Pilot Tone Squelch System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
Frequency Agility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3
Power Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
Microcontroller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
Antenna System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
Rear Panel Controls and Functions . . . . . . . . . . . . . . . . . . . . . . . . .1-4
XLR Jack. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4
Mode Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5
Power Input Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5
Antenna. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6
Front Panel Controls and Functions. . . . . . . . . . . . . . . . . . . . . . . . .1-6
PTX-3 Front Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6
OFF/TUNE/XMIT Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6
Power Up Sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6
Main Window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7
Frequency Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7
Audio Input Gain Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-8
Setup WIndow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-8
Rolloff Setup Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-9
COMPAT Setup Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-10
TUNING Setup Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-10
Frequency Window Behavior, based on TUNING mode selections .
1-12
User Programmable Frequency Group Behavior . . . . . . . . . . . .1-13
Adding/Deleting User Programmable Frequency Group Entries 1-13
Installation and Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-13
Operating Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-15
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-15
Frequency Blocks and Ranges. . . . . . . . . . . . . . . . . . . . . . . . . . . .1-17
Warranty Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .W-i
Technical Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .W-i
Vitec Group Communications
PTX-3 UHF Digital Hybrid IFB Transmitter
i
Warranty Repairs and Returns . . . . . . . . . . . . . . . . . . . . . . . . . . . . W-ii
Non-Warranty Repairs and Returns . . . . . . . . . . . . . . . . . . . . . . . . W-ii
Extended Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . W-ii
Liability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .W-iii
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PTX-3 UHF Digital Hybrid IFB Transmitter
Vitec Group Communications
Please read and follow these
instructions before operating
this product.
IMPORTANT SAFETY INSTRUCTIONS
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with dry cloth.
7. Do not block any ventilation openings. Install in accordan ce with the
manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat
registers, stoves, or other apparatus (including amplifiers) that
produce heat.
9. Only use attachments/accessories specified by the manufacturer.
10. Use only with the cart, stand, tripod, bracket, or table specified by
the manufacturer, or sold with the apparatus. When a cart is used,
use caution when moving the cart/apparatus combination to avoid
injury from tip-over.
11. Unplug this apparatus during lightning storms or when unused for
long periods of time.
12. Refer all servicing to qualified service personnel. Servicing is
required when the apparatus has been damaged in any way, such
as power-supply cord or plug is damaged, liquid has been spilled or
objects have fallen into the apparatus, the apparatus has been
exposed to rain or moisture, does not operate normally, or has been
dropped.
13. WARNING: To reduce the risk of fire or electric shock, do not
expose this product to rain or moisture.
Vitec Group Communications
PTX-3 UHF Digital Hybrid IFB Transmitter
Please familiarize yourself with the safety symbols in Figure 1.
When you see these symbols on this product, they warn you of
the potential danger of electric shock if the station is used
improperly. They also refer you to important operating and
maintenance instructions in the manual.
i
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
This symbol alerts you to the presence of uninsulated dangerous
voltage within the product's enclosure that might be of sufficient
magnitude to constitute a risk of electric shock. Do not open
the product's case.
This symbol informs you that important operating and maintenance instructions are included in the literature accompanying
this product.
Figure 1: Safety Symbols
SAFETY
Emission designator: 180KF3E
The T4 IFB transmitter is FCC type accepted under Part 74: 470 608MHz, 614 - 806MHz and 944.1 - 951.9MHz.
The FCC requires that the following statement be included in this
manual:
This device complies with FCC radiation exposure limits as set
forth for an uncontrolled environment. This device should be
installed and operated so that its antenna(s) are not co-located or
operating in conjunction with any other antenna or transmitter. A
separation distance of at least 20cm (8 inches) must be
maintained to comply with the FCC Radio Frequency Maximum
Permissible Exposure (MPE) requirements.
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PTX-3 UHF Digital Hybrid IFB Transmitter
Vitec Group Communications
GENERAL T ECHNICAL
1
DESCRIPTION
INTRODUCTION
The PTX-3 adds DSP capability a nd a convenient LCD inte rface to this
popular IFB transmitter, with the same physical size and interface
capabilities. The PTX-3 also of fers new features such as select able LF
roll-off and compatibility with some other popular brands.
The features include a graphics type backlit LCD display with a menu
system. The PTX-3 can be “Locked” to prevent a user from changing
any settings but still allow browsing of the current settings.
Vitec Group Communications
PTX-3 UHF Digital Hybrid IFB Transmitter
Figure 1-1: PTX-3 Digital Hybrid IFB Transmitter
The transmitter can be powered from any external DC source of 6 to
18 Volts at 200 mA maximum or from the provided 12 Volt power
supply with a locking power connector. The unit has an internal
self-resetting fuse and reverse polarity protection.
The PTX-3 is housed in a machined aluminum case with a tough
electrostatic powder coating. The front and rear panels are anodized
aluminum with laser etched engraving. The included antenna is a right
angle, ¼ wavelength monopole with a BNC connector, constructed of
polymer coated flexible steel cable.
These features, along with 250 milliwatt RF output power and a wide
range of selectable audio input types and levels, make the PTX-3 an
excellent choice for IFB and other applications where extended
operating range is required.
1-1
DIGITAL HYBRID TECHNOLOGY
The PTX-3 features Digital Hybrid Wireless* technology for
compatibility with some other brands of receivers. The Digital Hybrid
system in the PTX-3 overcomes channel noise and compandor
artifacts in a dramatically new way, digitally encoding the audio in the
transmitter and decoding it in the receiver, yet still sending the
encoded information via an analog FM wireless link. This proprietary
algorithm is not a digital implementation of an analog comp andor, but a
technique which can be accomplished only in the digital domain.
Figure 1-2: PTX-3 Block Diagram
AUDIO INPUT INTERFACE
The standard 3 pin XLR connector on the rear panel handles all audio
inputs. The four DIP switches allow setting the input sensitivity for low
levels, such as microphone inputs, or for high levels, such as line
inputs, balanced or unbalanced. The switches also offer special
settings to provide the proper input configurations to match to Clear
Com, RTS1, and RTS2 intercom systems. Pin 1 of the XLR input
connector is normally connected to ground but an internal jumper can
be moved if a floating input is desired.
While the XLR input does not offer phantom power, it is fully
compatible with standard 48 Volt phantom power. Phantom supplied
microphones may be connected to the PTX-3 without the need for DC
isolation.
A user-selectable low frequency roll-off can be set for 35 Hz or 50 Hz.
The recommended 50 Hz default setting helps to remove wind and
traffic noise, air conditioner rumble, and other sources of undesired low
frequency audio. The 35 Hz setting offers a fuller range of sound in the
absence of adverse conditions.
1-2
PTX-3 UHF Digital Hybrid IFB Transmitter
Vitec Group Communications
INPUT LIMITER
A DSP controlled analog audio limiter is employed before the
analog-to-digital converter. The limiter has a range of more than 30 dB
for excellent overload protection. A dual release envelope makes the
limiter acoustically transparent while maintaining low distortion. It can
be thought of as two limiters in series: a fast attack and release limiter
followed by a slower attack and release limiter . The dual release limiter
recovers quickly from brief transients but recovers more slowly from
sustained high levels, keeping audio distortion low while preserving
short term dynamic changes. When the audio meter on the LCD
display widens slightly as it reaches zero, limiting is indicated. When
the zero changes to a letter C, severe limiting and/or clipping is
indicated.
DSP COMPATIBILITY MODES
As a DSP based design, compatibility with a variety of dif ferent a nalog
and digital hybrid receivers is possible. The primary noise reduction in
the IFB system is a single band compandor with pre-emphasis.
When the PTX-3 is configured for compatibility with other types of
wireless systems; the DSP emulates the appropriate audio processing
and companding for the chosen mode.
PILOT TONE SQUELCH SYSTEM
Clear-Com IFB systems use a special “pilot tone” so that valid IFB
signals can be distinguished from RF interference. During normal
operation, an IFB receiver will listen for the distinctive pilot tone,
remaining silent (squelched) until the pilot tone is detected. The pilot
tone is located well above audio frequencies and is never passed
through to the receiver’s audio output.
The benefit of the pilot tone squelch system is that the receiver will
remain muted until it receives an RF carrier strong enough for good
reception and the pilot tone from the matching transmitter. Even strong
interfering RF signals on the carrier frequency of the system will not
open the squelch on the receiver.
When the PTX-3 is operated in compatibility modes other than IFB, it
generates pilot tones as appropriate for the chosen mode.
FREQUENCY AGILITY
The PTX-3 transmitter uses a synthesized, frequency selectable main
oscillator. The frequency is extremely stable over a wide temperature
range and over time. The transmitter’s standard tuning range covers
256 frequencies in 100 kHz steps over a 25.6 MHz band. This flexibility
significantly helps avoid interference problems in mobile or traveling
applications.
Vitec Group Communications
PTX-3 UHF Digital Hybrid IFB Transmitter
1-3
POWER DELAY
When powering the transmitter on and off, and when switching
between the XMIT and TUNE modes, intelligent circuitry adds brief
delays in order to allow time for circuits to stabilize, both locally and in
the matching receiver. These delays prevent clicks, thumps and other
transients in the audio.
MICROCONTROLLER
The microcontroller oversees most system operations, including RF
frequency and output, DSP audio functions, buttons and display, and
more. User settings are stored in non-volatile memory, so they are
retained even when the power is turned off.
TRANSMITTER
The PTX-3 transmitter operates at 250 mW to ensure a clean signal
free of dropouts and noise. All transmitter circuits are buffered and
filtered for excellent spectral purity. The clean RF signal reduces the
chances for interference in multiple transmitter installations.
ANTENNA SYSTEM
The included antenna is a right angle, ¼ wavelength monopole with a
BNC connector. It is constructed of polymer coated flexible steel cable.
The PTX-3’s 50 Ohm BNC output connector also works with a variety
of remote antennas for installation in studios and production trucks &
vans.
REAR PANEL CONTROLS AND FUNCTIONS
Figure 1-3: PTX-3 Rear Panel
XLR JACK
1-4
A standard XLR female jack accepts a variety of input sources
depending on the setting of the rear panel MODE switches. XLR pin
functions can be changed to suit the source depending on the
PTX-3 UHF Digital Hybrid IFB Transmitter
Vitec Group Communications
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