Chapter 8 445
IF Section
A5 IF Assembly
Figure 8-12 Region B Amplitude Offset
1 MHz Resolution Bandwidth Problems
Check the crystal shorting switches as follows:
1. On the spectrum analyzer, press
PRESET and set the controls as
follows:
Resolution bandwidth ................................................. 1MHz
Span .......................................................................... 500kHz
Center frequency ..................................................... 300MHz
2. On the spectrum analyzer, connect the 300 MHz CAL OUTPUT to
the INPUT 50 Ω.
3. If the trace flatness is not within 2.5 dB, a failure probably exists.
4. A trace similar to Figure 8-13 on page 446 indicates a crystal short
failure.
5. Press
SPAN to set the spectrum analyzer to 3 MHz. A trace that
slopes across the screen (see Figure 8-14 on page 447) indicates a
failed LC pole. To isolate the broken pole refer to the shape factor
information in "30 kHz Resolution Bandwidth Problems."
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