Tektronix WFM700 Series, Service Manual

Page: 130 / 194

Adjustments
3- 22
WFM700 Series Waveform Monitors Service Manual
Performing this procedure loads new calibration constants into the instrument.
This calibration routine is only available for the WFM700M (WFM700 with a
WFM7M module).
The following test items are required to perform the entire adjustment.
Adjustment requirements Recommended test equipment and test signal
Calibrated sine wave generator,
741.7582 MHz, 800 mV into
75
8 , FM modulated to generate
2 UI jitter amplitude
RF generator adjusted to 800 mV output into 75
8
at the
requested frequency.
With the recommended RF generator, you can modulate the
signal with the following settings to obtain 2 UI of jitter.
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
75
8
coaxial cable 36 inches long
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 connection.
3. Touch the Jitter HPF Adjust soft key and then the Start Jitter HPF
Adjustment soft key.
4. Adjust the displayed Measured Jitter amplitude using the General Purpose
Knob for a reading of 2.83 UI. See Figure 3--14.
5. Touch the Save and Exit soft key to save the new calibration constant.
Jitter HPF Adjust