Mpx Section - Pioneer sx-450 Service Manual

9 . 3 M P X S E C T I O N
1. Through 300 ohm dummy antenna, connect
FM signal generator to 300 ohm FM antenna
terminals.
2. Connect multiplex signal generator to extemal
modulation terminals of FM signal generator.
3. Connect oscilloscope horizontal input to MPX
signal pilot output and vertical input via probe
to TP (No. 13) of circuit board.
sx-450
4. Set SX-450 dial indication to 98MHz and adjust
FM signal generator for center of scale indi-
cation on AM/FM meter.
5. With FM signal generator unmodulated, adjust
VR1 so that lissajous pattern on oscilloscope
becomes stationary as shown in Fig. 12.
6. With MPX signal generator modulation lkHz,
L + R 67.5kHz deviation and pilot
7.5kHz
deviation, adjust T4 for minimum distortion.
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A C v o l t m e t e r D i s t o r t i o n m e t e r
F M s i g n a l g e n e r a t o r
D u m m y l o a d
O s c i l l o s c o p e
M P X s i g n a l g e n e r a t o r
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