5-6.
YO PRETUNE DAC, A54
Reference
Performance Test:
None
Service Section:
Sweep Generator
— YO
Loop
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).
DIGITAL VOLTMETER
DUT
Equipment
Digital Voltmeter (OVM)
HP 3456A
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 [INSTRPRESET]
b.
Press [CW] then enter [2]
[.]
[3]
[GHz]
to tune the YO to 2.3 GHz (minimum DAC output).
3. Connect the DVM to A54TP6 (VOAC) and adjust A54R22 (POFF, Figure 5-14) for —5.75
±
0.001
Vdc.
4. Press [CW]on the OUT, then enter [6] [9] [9] [9]
[.]
[9] [9] [9] [9] [9] [MHz]to set the YO close to
7 GHz (maximum DAC output).
5. Adjust A54R14 (PGN, Figure 5-14) for —17.5
±
0.001 Vdc.
Figure 5-13.
YO Pretune DAC Gain Test Setup
HP 8340B/41B
Adjustments
5-37