3 mpx section – Pioneer sx-450 User Manual

Page 10

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SX-450

9.3 MPX SECTION

1. Through 300 ohm dummy antenna, connect

FM signal generator to 300 ohm FM antenna

terminals.

2. Connect multiplex signal generator to external

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.

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

VRl so that lissajous pattern on oscilloscope

becomes stationary as shown in Fig. 12.

6. With MPX signal generator modulation IkHz,

L + R 67.5kHz deviation and pilot 7.5kHz

deviation, adjust T4 for minimum distortion.

VRl

AC voltmeter Distortion meter

FM signal generator

Fig. 12