Agilent Technologies 856290216 service manual Automatic if Adjustment, Sweep Width Settings

Table 9-3. Sweep Width Settings

Sweep Width Sweep Time Res BW RANGE MA1 MAO

Adjusted A4U105 A4U105 A4U105

Pin6 Pin2 Pill5

20 kHz	5	ms	10 kHz	+5	v	ov	ov
10 kHz	10	ms	3 kHz	+5	v	ov	+5 v
4 kHz	30 ms		1 kHz	+5	v	+5v	ov
2 kHz	15	ms	300 Hz +5 V			+5 v	+5 v

Automatic IF Adjustment

The spectrum analyzer performs an automatic adjustment of the IF Section whenever needed.

The cal oscillator on the A4 assembly provides a stimulus signal which is routed through the IF during the retrace period.

The A3 Interface assembly measures the response using its analog-to-digital converter (ADC). The spectrum analyzer turns the cal oscillator off during a sweep.

When IF ADJ is ON, the spectrum analyzer readjusts part of the IF circuitry during each retrace period to readjust the IF completely every 5 minutes.

Automatic IF adjustment is performed upon the following conditions:

nPower on: (unless STOP ALIGN is pressed). The IF parameter variables are initialized to

values loaded in program ROM and all possible IF adjustments are made. If STOP ALIGN is pressed, the adjustment is halted.

nIf REAXGI? LO & IF is selected: All possible IF adjustments (and LO adjustments) are made with the most recent IF parameter variables used as the starting point.

wIf FULL IF AD3 is selected: All possible IF adjustments are made with the most recent IF parameter variables used as the starting point. (FULL IF ADJ is located in the (CAL) menu.)

. If ADJ Cm IF STATE is selected: All amplitude data and some resolution bandwidths are adjusted. The bandwidths adjusted are a function of the currently selected resolution bandwidth setting.

H Between sweeps: IF ADJ must be set to ON. When IF ADJ is OFF, an A is displayed along the left side of the graticule.

If a FULL IF ADJ sequence cannot proceed beyond the amplitude portion, check the output of the cal oscillator on the A4 assembly as follows:

1.Disconnect cable W52 ( coax 9) from A5J4. Connect cable W52 to the input of a second spectrum analyzer.

2.Set the second spectrum analyzer center frequency to 10.7 MHz and the reference level to - 3 0 dBm.

3.On the spectrum analyzer under test, press FULL IF ADJ and observe the display of the second spectrum analyzer

IF Section 9-9