Adjustment Procedures
5-44 2715 Spectrum Analyzer Service Manual
Use the following procedureto adjust C21, C22, C23, C24, R63, R59, and L11
on the VideoDemod board:
TestSetup. C onnectinstruments as follows:
HTest equipmentrequired:
PAL/NTSC Signal Generator
CATVModulator
Test Spectrum Analyzer
Tracking Generator
HSelect the following settings on the test instruments:
Test Spectrum Analyzer
Center Frequency 100 MHz
Span/div 5 MHz
Reference Level -- 20 dBm
Vertical Scale 10dB /div
Resolution 5 to 1 MHz
Test Tracking Generator
Output Level --20dBm
HMount video demod board on extenderboard.
HRemove the connectors to the videodemod board 110MHz OUT and
110MHz IN.
HConnect the output of the tracking generator to the RF Input of the test
spectrum analyzer using two cables conn ected together with an SMB
connector.These cables will later be connected to the Video Demodulator
board (next step).
The test spectrum analyzerdisplay should be a nearly flat line near the top of
the screen (referencelevel). Adjust the output level (fine) of the tracking
generator to position the trace at the test spectrumanalyzer reference level
(top of screen) overthe frequency range of 105 MHz to 115 MHz.
HConnect the output of the tracking generatorto the Video Demod board
110M IN connector.(This connector is an SMB connector and will require
an adapter cable.)
HConnect the TP110M (SMB connector)from the Video Demod board to the
test spectrum analyzer’s RF input.
Video DemodAdjustment Procedure