Agilent Technologies 856290216 service manual 300 MHz

582 AMPL Unable to adjust 100 kHz resolution bandwidth and resolution bandwidths less than or equal to 10 kHz. Bad CALOSC Calibration in Sweep Rate. Test the 100 kHz resolution bandwidth filter 3 dB bandwidth as follows:

1.Connect the CAL OUTPUT signal (A4J8) to the INPUT 500.

2.Press (W) and set the controls as follows:

Center frequency	300 MHz
Span	..5OOkH z
Resolution bandwidth	100 kHz
Log dB/div	1 dB

Reference level . . adjust to place signal peak at top of the screen

3.Press (PEAK SEARCH) and MAEEEE DELTA and turn the knob clockwise to position the marker until the delta MKR reads -3 dB f O . l dB.

4.Press MAEEEE DELTA and move the marker to the other side of the peak until the delta MKR reads 0 dB fO.l dB.

5.If the delta MKR frequency is between 90 kHz and 110 kHz, the

100 kHz resolution bandwidth is working properly. If the frequency is outside these limits, read the following information on the A4 Cal Oscillator sweep generator.

If the 100 kHz resolution bandwidth works properly, the cal oscillator sweep generator is failing to sweep its oscillator frequency at the correct rate. The error is detected in sweeping on the skirts of the 100 kHz resolution bandwidth.

A properly operating sweep generator generates a series of negative-going parabolas. These parabolas generate the sweeps used to adjust resolution bandwidths of 10 kHz and below. Check the sweep generator with the following steps. Refer also to “300 Hz to 3 kHz resolution bandwidth Out of Specification” in the A4 Cal Oscillator troubleshooting text in Chapter 9, “IF Section.”

1.Remove the shields.

2.Connect an oscilloscope probe to A4U804C pin 8.

3.On the spectrum analyzer, press ICAL) and FULL IF Al3J.

4.Approximately 8 seconds after starting the FULL IF ADJ , check for negative-going parabolas (similar to half-sine waves) 5 ms wide and approximately -4 V at their peak. Refer to Chapter 9, “IF Section,” for more information on the A4 Log Amp/Cal Oscillator Assembly.

7-36 General Troubleshooting