Yo Pretune Dac, A54 - HP 8340B Manual

5-6. YO PRETUNE DAC, A54

Reference
Performance Test: None
Service Section: Sweep Generator
Description
This procedure makes gain and offset adjustments to the pretune voltage such that the lowest output
voltage from the DAC will tune the YO to its lowest frequency (2.3 GHz), and the highest voltage out of
the DAC (full scale) will tune the YO to its highest frequency (7 GHz).
Equipment
Digital Voltmeter (OVM)
Procedure
1. Position the OUT in the test position as shown in Figure 5-13 with bottom cover removed and turn
the LINE switch on. Connect the test equipment as shown in Figure 5-13 and allow one-half hour
warm up time. Be sure to connect DVM ground to A54TP7 RGNO.
2. Set the OUT as follows:
a. Press [INSTR PRESET]
b. Press [CW] then enter [2]
3. Connect the DVM to A54TP6 (VOAC) and adjust A54R22 (POFF, Figure 5-14) for —5.75
Vdc.
4. Press [CW]on the OUT, then enter [6] [9] [9] [9]
7 GHz (maximum DAC output).
5. Adjust A54R14 (PGN, Figure 5-14) for —17.5
HP 8340B/41B
Loop
— YO
DIGITAL VOLTMETER
Figure 5-13. YO Pretune DAC Gain Test Setup
[GHz]
[3] to tune the YO to 2.3 GHz (minimum DAC output).
[.]
0.001 Vdc.
±
DUT
[9] [9] [9] [9] [9] [MHz]to set the YO close to
[.]
HP 3456A
0.001
±
Adjustments 5-37