Adjustment Procedures
2715 Spectrum Analyzer Service Manual 5-47
Adjust Video Detector. Adjust L11 as follows:
1. Connect the TSG 95 VideoOutput to the TVM450 Video Input. Connect the
TVM450’s --20 dB RF TES T Output to the2715 R F INPUT.
2. Set the TSG 95 to produce a 5-Step Grayscaleand set it to the desired video
format (NTSC or PAL).
3. Set the TVM450 output to Channel 4 and the RF level control full counter-
clockwise.
NOTE. Be sure the OFFSET switch on the rearpanel of the TVM450 is set to OFF.
4. Check that the VIDEO MODULATIONand VIDEO/AUDIO RATIO
controls on the TVM450 are both set to mid range(detent) and that the
AUDIO DEVIATIONcontrol is set full counterclockwise.
5. Select the following settings on the 2715:
CENTER FREQUENCY 67. 25 MHz
SPAN/DIV 2 MHz
Calibrator Signal OFF
6. Set the signal (visual carrier) to the top graticulewith the REF LEVEL ↑and
↓controls.
7. Set SPAN to ZERO.
8. Activate the VD DAC TO VIS CARR function by pressing UTIL526.
9. Select the following settings on the test oscilloscope:
VerticalMode CH1
CH 1 Volts/Div. 500 mV
CH 1 Coupling DC
Time/Div. 10s
Trigger Mode Auto
Trigger Source CH 1
Trigger Coupling DC
10. Connect the oscilloscope channel 1 probe to the VideoDemod VIDEO TP.
11. Tune L11 until the test oscilloscopedisplays a video signal as illustrated in
Figure 5--18.
NOTE. It will probably be necessaryto adjust the test oscilloscope trigger level
control to obtain a stable display.