HP 8568B Note, Optional, 11. Down/Up Converter Adjustments, Figure 3-51.Location of Down/Up Converter Adjustments

11. Down/Up Converter Adjustments

6.Adjust A4A6AlR29 WIDE GAIN to align markers on CRT display. MKR A level should indicate 1.00 X. See Figure 3-51 for location of adjustment.

7.Disconnect CAL OUTPUT from RF INPUT.

Optional

Note	Perform the following procedure if the A4A6Al assembly is replaced
	or the A4A6Al 21.4 MHz Bandpass Amplifier Filter is worked on.

1.Disconnect CAL OUTPUT from RF INPUT.

2.Key in [REFERENCE LEVEL) -70 dBm, [REs] 1 kHz, and MARKER IOFF).

3.Set the second spectrum analyzer’s to the following settings:

RESOLUTION BANDWIDTH . . . . . . . . . . . . . . . . . . 100 kHz

FREQUENCY SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 MHz

CENTER FREQUENCY . . . . . . . . . . . . . . . . . . . . . . 18.4 MHz

RF ATTENUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 dB

REFERENCE LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 dBm

SCALE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LOG 10 dB/div

4.Connect the second spectrum analyzer to A4A4TP7 using and active probe. See Figure 3-50 for test setup.

5.Adjust A4A6AlC31 18.4 MHz NULL to null the 18.4 MHz Local Oscillator signal and all displayed harmonics. See Figure 3-51 for location of adjustment.

	A4A6 D O W N / U P			C O N V E R T E R
				\
						2
r		R2’	1.		, 18 4 ,“,‘; NIJLL	WIDE,< :AlN	AZR33

Figure 3-51. Location of Down/Up Converter Adjustments

6.18.4 MHz signal and displayed harmonics should be below -10 dBm (-30 dBm on display due to 1O:l divider). If unable to adjust A4A6AlC31 18.4 MHz NULL for proper indication, increase value of A4A5RlO. See Figure 3-49 for the location of A4A5RlO. Refer to ‘Iable 3-3 for range of values.

Adjustments 3-93