HP 3336A - Page 139

Model 3336A/B/C Adjustments
EXT. REF IN
-hp- 3336 SPECTRUM ANALYZER (LOW FREQ.)
fe Prs Bl ie CREED )
75/
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ae ae es ee ae ee
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75.Q OUTPUT
MIN LOSS
IMPEDENCE MATCHING PAD
IMHz
LOW PASS
FILTER
Figure 5-1. API 100 kHz Spur Adjustment Set Up
NOTE 1
This adjustment procedure applies only to newer -hp- 3336s with
the A21 Frequency Synthesis board, not the original Al board. On
the old Al assembly, R107 is not adjustable.
& NOTE 2
Although A21TP11 is used as a monitoring point in the previous
adjustment (API Current Source Adjustment), paragraph 5-13), it
cannot be used with this adjustment set-up because the
141T/8552B/8553B has a 50 Q input only.
d. Set up the spectrum analyzer as follows:
FANE, 6: sce heaa RAR aN wee aie? 0 - 11 MHz
center frequency ................0005 100 kHz
scan Width ............ ccc cee ee eee 20 kHz/div
bandwidth .......... 0.0... cee eee 3 kHz
scan time .......... 00. cece ee eee 10 msec/div
video filter... 0.0... cece ee eee 10 kHz
ref level ....... 0... cece eee eee reece —40 dBm
e. Misadjust A21R107 until the 100 kHz spur is clearly visible.
f. Zoom in on that spur by adjusting the center frequency and scan width then the band-
width and scan time until the analyzer is adjusted to:
center frequency ..................4. ~ 100 kHz
scan Width ............ cece cece cece 0.1 kHz/div
bandwidth ................c cee eee 0.03 kHz
& SCAN (IMG 7s t0 acts tows es SNe kh eee 0.2 sec/div
5-5