Tektronix WFM700 Series, Service Manual

Page: 71 / 194

Performance Verification
WFM700 Series Waveform Monitors Service Manual
2- 39
This test checks the jitter high pass filter attenuation at the selected frequency.
This procedure is only applicable for a WFM7M Input Module.
Performance Requirement. This test verifies performance characteristics and is
listed in the test record.
NOTE
. If this test is performed out of sequence or the sequence of tests has been
interrupted (such as power off or input from another module was selected),
perform the steps in this note to prepare the instrument to continue testing.
a. Connect the SD video generator to INPUT B using a 75
8
cable.
b.
Set the SD video generator for a 525-format 100% color bar signal.
c. Press the INPUT button and select Input B .
d. Press the EYE button.
e. Press the INPUT button and select Input A .
1. Install the 50
8
N-to-BNC adapter on the RF generator output.
2. Connect the RF generator output to INPUT A using a 75
8
cable. Imped-
ance matching is not important for this test.
3. Set the RF generator as follows:
Frequency 741.7582 MHz
Output Level 0 dB
Frequency Modulation OFF
LFGEN2 Frequency 10 Hz
LFGEN2 Waveshape SINE
Phase Modulation Source LF2
Phase Deviation 6.28 RADIANS
RF Output ON
Phase Modulation ON
4.
Press the
EYE
button and then touch the
Display
soft key.
5.
Touch the
Jitter
soft key and then touch the
Done
soft key.
6. Touch the Hi Pass Filter: soft key and set to 10 Hz .
7. Read the Measured Jitter amplitude (in UI) displayed on screen.
8. Calculate the jitter response in db using the formula:
Jitter Response
20
log
10
Æ
Measured Jitter
4 UI
É
9.
CHECK that the calculated response is between –2 dB and –4 dB.
Jitter Display High Pass
Filter (WFM7M only)