Agilent Technologies 856290216 service manual MHz Resolution Bandwidth Problems, 500

1 MHz Resolution Bandwidth Problems

Check the crystal shorting switches as follows:

1. On the HP 85623 spectrum analyzer, press (-1 and set the controls as follows:

Resolution bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 MHz Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500kHz Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...300 MHz

2.On the HP 85623 spectrum analyzer, connect the 300 MHz CAL OUTPUT to the INPUT

500.

3.If the trace flatness is not within 2.5 dB, a failure probably exists.

4.A trace similar to Figure 9-13 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 9-14) indicates a failed LC pole. To isoiate the broken pole refer to the shape factor information in “30 kHz Resolution Bandwidth Problems.”

+ATTEN 1 0 d B
R L 0dBm	lBdB/

C E N T E R 300.0000MHz		S P A N 500.0kHz
*RBW 1.0MHz	V B W 1.0MHz	SWP 50ms

S K 1 8 2

Figure 9-13. Faulty Crystal Short

IF Section 9-29