Teledyne QPHY-UWB User Manual
QPHY-UWB
UWB Serial Data
Operator’s Manual
Revision C – October, 2008
Relating to the Following Release Versions:
• Software Option Rev. 5.7
• UWB Script Rev. 1.4
• Style Sheet Rev. 1.2
LeCroy Corporation
700 Chestnut Ridge Road
Chestnut Ridge, NY 10977–6499
Tel: (845) 578 6020, Fax: (845) 578 5985
Internet: www.lecroy.com
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requested trademarks of their respective holders. Information in this publication supersedes all earlier versions.
Specifications subject to change without notice.
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Visit www.lecroy.com to view the
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Document Number: 915837 Rev C
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QPHY-UWB-OM-E Rev C
TABLE OF CONTENTS
QPHY-UWB Software Option
OVERVIEW ................................................................................................................................ 5
INSTALLATION ......................................................................................................................... 6
Oscilloscope Option Key Installation .......................................................................................................................... 6
Oscilloscope Firmware Version: ................................................................................................................................. 6
BASIC SETUP FOR CAPTURING UWB PACKET OVER CABLE ........................................... 7
Sample Rate and Bandwidth Setup ........................................................................................................................... 7
Vertical Setup ............................................................................................................................................................. 7
Trigger and Timebase Setup ...................................................................................................................................... 7
CAPTURING A WIRELESS USB DATA PACKET ................................................................... 8
Antenna, Amplifier, and Filter ..................................................................................................................................... 8
Adding a Special Trigger Path .................................................................................................................................... 8
OVERVIEW OF UWB ANALYSIS MODE .................................................................................. 9
Turning the UWB Analysis Mode On and Off ........................................................................................................... 10
Selecting the Source for the UWB Waveform to be analyzed ................................................................................. 11
Specifying the MB-OFDM parameters for the packet to be analyzed ...................................................................... 11
Setting the Time Frequency Code (TFC) ......................................................................................................... 11
Setting the Band Group .................................................................................................................................... 12
Setting the Data Rate ....................................................................................................................................... 12
Interpreting the Packet Information Box ................................................................................................................... 13
Selecting the Analysis View and Associated Menus ................................................................................................ 13
SPECTROGRAM ANALYSIS .................................................................................................. 14
Setting the Center Frequency and Frequency Span ........................................................................................ 14
Dynamic Range ................................................................................................................................................ 15
POWER SPECTRAL DENSITY (PSD) ANALYSIS ................................................................. 16
Modifying the Symbol Timing Window ..................................................................................................................... 17
Mask Pass/Fail View ................................................................................................................................................ 18
Adjacent Channel Power Ratio (ACPR) View .......................................................................................................... 19
BAND POWER ANALYSIS ..................................................................................................... 20
ERROR VECTOR MAGNITUDE (EVM) & CONSTELLATION ANALYSIS ............................. 21
Real and Imaginary Waveforms (I and Q components) ........................................................................................... 22
Error Vector Magnitude (EVM) Measurement Parameter ........................................................................................ 22
Frequency Error Measurement Parameter .............................................................................................................. 23
EVM/Constellation Controls ..................................................................................................................................... 23
Include in Constellation and EVM ..................................................................................................................... 23
Selected Packets and Selected Symbol ........................................................................................................... 24
MAGNITUDE AND PHASE ANALYSIS .................................................................................. 25
Selecting a Specific Packet and Symbol to Display ................................................................................................. 25
Selecting Subcarrier Types to Display ..................................................................................................................... 26
Setting the Trace Style ............................................................................................................................................. 27
COMMON PHASE ERROR (CPE) VERSUS TIME ANALYSIS .............................................. 28
AUTOMATING UWB MEASUREMENT TAKING WITH QUALIPHY ...................................... 29
General Setup Dialog ............................................................................................................................................... 29
Standard Selection Dialog ........................................................................................................................................ 29
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Configuration Dialog ................................................................................................................................................. 29
Edit/View Configuration Dialog ................................................................................................................................. 29
Generating a Report ................................................................................................................................................. 30
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QPHY-UWB-OM-E Rev C
QPHY-UWB Software Option
OVERVIEW
The LeCroy QPHY-UWB option software enables LeCroy Digital Oscilloscopes to perform WiMedia ultra
wideband (UWB) physical layer (PHY) transmitter compliance measurements as well as provide analyses and
displays for troubleshooting UWB transmitters. This option software performs the analyses and tests in
accordance with the following documents available from the WiMedia Alliance (WiMedia.org):
• MultiBand OFDM(Orthogonal Frequency Division Modulation) Physical Layer Specification, version 1.0
• WiMedia PHY Test Specification, version 1.0
Some additions have also been made to accommodate PHY specification version 1.2 such as the addition of
band group 6 and the addition of the 2-band time frequency interleave modes (TFI2), Time Frequency Codes
(TFC) 8-10.
The WiMedia UWB PHY specification provides for broadcasting over 14 bands, each 528 MHz wide covering the
frequency range from 3.1 GHz to 10.6 GHz. The 14 bands form 6 band groups detailed in the table below. The
table indicates which oscilloscopes will provide adequate bandwidth depending on which band groups you are
working in.
Band
Group
Band
IDs
Number
Bands
Lower
Freq
(MHz)
1 1 – 3 3 3168 4960 4752 1584
2 4 – 6 3 4752 5544 6336 1584
3 7 – 9 3 6336 7128 7920 1584
4 10 – 12 2 7920 8712 9504 1584
5 13 – 14 3 9504 10032 10560 1056
6 9 – 11 3 7392 8184 8976 1584
Center
Freq
(MHz)
Upper
Freq
(MHz)
Bandwidth
(MHz)
LeCroy
Oscilloscope
SDA760Zi/DDA760Zi/WP760Zi/
SDA6000/9000/11000/13000
SDA9000/11000/13000
SDA9000/11000/13000
SDA11000/13000
SDA11000/13000
SDA11000/13000
This software expects the transmitter under test to be utilizing both the Time-frequency Codes and the OFDM
modulation scheme as required by the MB-OFDM specification. The software expects to receive an entire
digitized RF MB-OFDM packet. The software will down convert from RF to baseband and then further demodulate
the OFDM symbols for analysis.
The basic QPHY-UWB option is well integrated into the oscilloscope software. Control of the measurement
software is accomplished via a set of UWB menus that are entered from the top level menu Analysis UWB
(WiMedia). These menus allow you to set up the parameters of the transmitter (Band Group, TFC, Data Rate) as
well as the type of analysis and details of the analysis.
The QPHY-UWB option supports the following types of analysis:
• Power Measurements
o Spectrogram
o Power Spectral Density plots with masks and ACPR
o Band power and total power
• Modulation Measurements
o Error Vector Magnitude (EVM) and constellation plot
o Phase and Magnitude versus subcarrier plots
o Common Phase Error versus time (symbol)
The QPHY-UWB option supports automation of WiMedia PHY compliance testing via our QualiPHY software. A
QualiPHY script is provided with the QPHY-UWB software to perform most oscilloscope operation, results
storage, and report generation for the compliance testing automatically. The software will pause and prompt the
user when a change in the transmitter parameters is required. It then asks the user to trigger the oscilloscope and
make sure that a packet was properly captured, after that, the script handles the analysis and results
automatically. The use of the QualiPHY and the UWB QualiPHY script is discussed in the Automating UWB
measurement taking with Qualiphy section on page 29.
QPHY-UWB-OM-E Rev C
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INSTALLATION
The QPHY-UWB option is enabled through installation of an option key. If the option was purchased with the
oscilloscope, then the key will already have been installed and nothing further is required to gain access and
control of the option. If the option was purchased independently of the oscilloscope and needs installation, then
please follow the instructions in the next section.
Oscilloscope Option Key Installation
If an option key has not yet been purchased to enable the QPHY-UWB option, call LeCroy Customer Support to
place an order and receive the code.
Enter the key and enable the option as follows:
1. From the oscilloscope menu select Utilities Utilities Setup...
2. Select the Options tab and click the Add Key button.
3. Enter the Key Code using the on-screen keyboard.
4. Restart the oscilloscope to activate the option after installation.
Oscilloscope Firmware Version:
In order to enable the features described in this documentation version 5.2.0 or later firmware should be installed.
If your oscilloscope has an earlier version of the firmware, please download the latest version from the LeCroy
website (www.lecroy.com) and install on oscilloscope. Note that you do not need to re-install the option keys when
you update the firmware.
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QPHY-UWB-OM-E Rev C
QPHY-UWB Software Option
Band
BASIC SETUP FOR CAPTURING UWB PACKET OVER CABLE
Configure the UWB transmitter to be tested to the desired Band group, TFC, and data rate. It will make setup of
the trigger easiest if your transmitter can be put in a mode to continuously send out packets. The trigger can still
be setup even if you can only send out a finite burst of packets or even only 1 packet at a time, but it is a little
more difficult. Cable the antenna output of the transmitter to the input channel of the oscilloscope. Note for
40GS/s sampling rate only channel 2 or 3 can be used. If the UWB radio needs to be transmitting over the air
simultaneously with the capture of the signal, then use an appropriate power splitter to split the signal between
the antenna and the oscilloscope.
Sample Rate and Bandwidth Setup
Set up the oscilloscope sample rate and bandwidth according to the table below. Except for use with band group
1, the oscilloscope should be set to DBI mode on. This is accessible under the Timebase menu. Make sure that
the Timebase mode is set to Fixed sample rate. You do not want this changing while you are making a
measurement.
Group
1 SDA760Zi/DDA760Zi/
2 - 3 SDA9000
4 - 6 SDA11000
Oscilloscopes Bandwidth Sample Rate DBI Mode on? Channel
WP760Zi/SDA6000
SDA9000
SDA11000
SDA13000
SDA11000
SDA13000
SDA13000
6 GHz 20 GS/sec No Any
9 GHz
11 GHz
13 GHz
11 GHz
13 GHz
40 GS/sec Yes 2 or 3
40 GS/sec Yes 2 or 3
Vertical Setup
Start with a vertical sensitivity of 50 mV/div. After you capture the first few packets, set the vertical sensitivity
control to variable and adjust the V/div so the packet amplitude takes up at least 6 vertical divisions, but doesn’t
go off-screen.
Trigger and Timebase Setup
Set trigger to edge trigger with a trigger level of about ½ division (25 mV). Using the trigger delay control, place
the trigger position at about 2 divisions from the left of the screen. The trigger will not trigger precisely at the same
time each sweep, so you need to leave some room on the left of the screen. You also need to insure that there is
at least 200 nsec of inter-packet gap captured before the packet starts in order for the software to recognize the
packet as a complete packet for analysis. Set the time per division to a long enough time to capture the number of
packets you wish to analyze at a single time. Adjust trigger level to give most stable trigger. This may take some
back and forth if your transmitter is not transmitting a continuous stream of packets.
Note:
According to the MultiBand OFDM Physical Layer Specification 1.1 (©2005 MultiBand OFDM Alliance and WiMedia
Alliance), EVM is only computed on data symbols. With a Standard preamble, the first data (PSDU, payload) symbol is symbol
43.
Although our software does not require it, you should acquire full packets. The WiMedia PHY Compliance and Interoperability
Test Specification (v1.0, September 1, 2006) says “EVM shall be computed over at least 3 packets with a payload of at least
96 symbols each. If the measured EVM is within 2 dB of the specified EVM maximum in absolute value, abs (measuredEVM specEVM) < 2 dB, then the EVM should be re-measured over an average of 10 packets to ensure accuracy of the
measurement”.
Please see the WiMedia PHY Compliance and Interoperability Test Specification for more details.
When you have at least one full packet on the screen, then you can proceed to analyze the packet which is
described starting on page 9.
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CAPTURING A WIRELESS USB DATA PACKET
The block diagram below shows a setup that is useful for capturing a UWB packet within the context of a Certified
Wireless USB (WUSB) system.
Antenna, Amplifier, and Filter
The amplifier is needed in order to be able to move the capture antenna out of the near field of the transmit
antenna. Our experience indicates that the capture antenna will still need to be relatively close to the transmitter
antenna, < 15 centimeters in order to obtain adequate signal to noise ratio. An appropriate band pass filter should
be used in environments where there are larger amounts of ambient cell phone or other wireless transmissions.
These out-of-band transmissions will not at low levels significantly affect the UWB analysis, but if they get too
high, they can use up too much of the oscilloscope dynamic range and decrease the SNR of the UWB
measurement. They also can make it more difficult to trigger on the UWB packet.
Adding a Special Trigger Path
In the above setup, the signal is split into 2 paths so that we can improve the triggering. In a Wireless USB
system, most of the UWB packets are very short “beacon” packets which we do not want to trigger on. We only
want to capture the much longer packets carrying the data payload. In order to accomplish this, we need to use
the Width Trigger mode in the oscilloscope to trigger on only the long packets. The Width Trigger mode has a
much lower bandwidth than the edge trigger, approximately 750 MHz. So we need to create a triggering path
where we use a shottky diode detector (e.g., Anritsu 70KA50) driving a high impedance input to create a rectified
and filtered version of the signal. The signal “envelope” seen by Channel 3 will be pulled slowly low as the packet
starts and will stay low for the duration of the packet and then slowly return to 0V. With this circuit, we can now
use the Width Trigger to trigger only on negative going pulses with width greater than the width of the undesired
short packets. See the oscilloscope Operator’s Manual for help using the Width Trigger. This detector based
triggering circuit can also be used to help trigger on packets in higher frequency band groups where the edge
trigger bandwidth of the oscilloscope is being exceeded or pushed to limited sensitivity.
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QPHY-UWB-OM-E Rev C
QPHY-UWB Software Option
OVERVIEW OF UWB ANALYSIS MODE
Once installed, the UWB (WiMedia) selection will appear in the Analysis menu. This is the main entry point into
the UWB analysis mode. Notice that the packet to be analyzed displayed on the screen below is in Memory 1,
M1. Click UWB (WiMedia) to enter the UWB analysis mode.
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