MODEL8559A

ADJUSTMENTS

ADJUSTMENTS

5-26.SECOND CONVERTER ADJUSTMENTS(Cont'd)

nr n ALT IF on and verify that the two signals do not appear to move. Change spectrum analyzer FREQ SPAN/DIV to 500 kHz.

Repeat steps 7 through 14 if necessary to align both signal identifier signals and both alternate IF signals and spaced 1 MHz (2 divisions) apart on the CRT display.

Depress front-panel ALT IF pushbutton. Turn SIG IDENT off.Note Second LO frequency on frequency counter.

Adjust A5Z4 2nd LO FREQUENCY if necessary for a frequency counter indication of 2671.1 MHz +0.5 MHz.

If second LO frequency is readjusted, recheck second LO shift adjustments,steps 5 through 16.

Set spectrum analyzer controls as follows:

 

FREQSPAN/DIV ..........................................................

2MHz

RESBW ..................................................................

3MHz

REFLEVELdBm ............................................................

-10

INPUTATTEN .............................................................

10dB

Amplitudescale .........................................................

ldB/DIV

TIME/DIV ................................................................

AUTO

FREQUENCYBANDGHz ...........................................

Band1 (.01-3)

ALTIF ......................................................................

ON

SIG IDENT .................................................................

OFF

Adjust front-panel REF LEVEL dBm and REF LEVEL FINE controls to place signal peak in upper half of CRT display for convenient viewing.

Adjust front-panel TUNING control to place signal peak 3.75 divisions to the left of center screen on the CRT.

Connect the HIGH output of the function generator to an oscilloscope and adjust function generator output for a OV to +20V ramp and frequency to 500 Hz.

Disconnect the function generator from the oscilloscope and connect it to A5A2TP1 VARACTOR by using the 8120-1292adapter.

The following adjustments refer to aligning the Second Converter after internal repair of the converter. If the entire converter has been replaced, it will probably not be necessary to perform all of the adjustments.

Adjustments A5Z1, A5Z2, A5Z3, and A5L2 are used to align the bandpass filter and output match of the Second Converter. Z1 and L2 are used to adjust amplitude and 22 and 23 are used to center the response about the center frequency.