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Performance Verification
2715 Spectrum Analyzer Service Manual
4-33
This procedure assures the proper operation of the Video Demodulator and the
gated measurement circuitry. Since this is not a Performance Requirement,
typical values are used throughout the procedure.
H Test equipment required:
PA L/NTSC Signal Generator (TSG 95)
CATV Modulator (TVM450)
1. Connect the TSG 95 Video Output to the TVM450 Video Input.
2. Connect the TVM450 --20 dB RF TEST Output to the 2715 RF INPUT.
3. Set the TS G 95 to produce 5-Step Grayscale and set it to the desired video
format (NTSC or PAL).
4. Set the TVM450 output to Channel 4 and the RF level control full counter-
clockwise.
NOTE. Be sure the Offset switch on the rear panel of the TVM450 is set to OFF.
5. Check that the VIDEO MODULATION and VIDEO/AUDIO RATIO
controls on the TVM450 are both set to midrange (detent) and that the
AUDIO DEVIATION control is set full counterclockwise.
6. Select the following settings on the 2715:
FREQUENCY 67.25 MHz
RESOLUTION BW 300 kHz
VID FLTR OFF
DISPLAY STORAGE D (only)
REFERENCE LEVEL +30 dBmV
7. Press PEAK FIND, CTR-MEAS/TRKG and manually reset the center
frequency to the actual counted visual carrier frequency.
8. Press ZERO (SPAN) and set Sweep Speed to 100 s/div.
9. Press UTIL526to tune the video demodulator to the visual carrier.
10. Press 7 to activate the AFC. If it indicates ON, press 7 twice more to toggle
it OFF then back ON.
11. Press 8 to select GATING. If it already indicates GATING, press 8 twice
more to toggle it through NOR back to GATING.
12. Press any MENU key to exit the menus, and turn off the readouts. Check
that the display is similar to that illustrated in Figure 4--7.
Video Demodulator and
Gating Verification