13. Sweep, DAC, and Main Coil Driver Adjustments
RF-Section:
Al6 Scan Generator
A19 Digital-to-Analog Converter (DAC)
A20 Main Coil Driver
Center Frequency Readout Accuracy Test
Frequency Span Accuracy Test
Sweep Time Accuracy Test
The Sweep Time is adjusted first by viewing the Scan Ramp on an
oscilloscope and adjusting for proper levels. Next, the AUX OUT Ramp
(SWEEP RECORDER OUTPUT) is adjusted to produce a continuous
stepped ramp over multi-band sweeps. Offset adjustments are
performed on both the Al6 Scan Generator and A19 DAC Assemblies
to set the start voltages of the various sweep and span ramps. The
A20 Main Coil Driver Assembly is adjusted to set the two frequency
end-points of the YIG-tuned oscillator. Finally, frequency span
accuracy for YTO Spans
MHz) is adjusted by adjusting the Sweep
Attenuator
gains
on the Al6 Scan Generator Assembly and the 5.8
and 12.5
Band Overlap adjustments on the A19 DAC Assembly.
Adjustments in this procedure affect
tracking. Adjustment
Procedure 2 1, “Frequency Response Adjustments” should be
performed after this procedure to ensure specified performance.
Universal Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 5316A
Synthesized Sweeper . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HP
Digitizing Oscilloscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 54501A
Divider Probe, 10
. . . . . . . . . . . . . . . . . . HP 10432A
Digital Voltmeter (DVM) . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 3456A
Frequency Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 5343A
Adapters:
Adapter, BNC (f) to SMA (m) . . . . . . . . . . . . . . . . . . . . . . . HP 1250-1200
Cables:
Low-Loss Microwave Test Cable (APC 3.5) . . . . . . . . . . . HP 8120-4921
Adjustments 3-l 13