HP 8568B, Руководство по испытаниям и регулировке работы, Страница: 245 / 313

20. 50 MHz Voltage-Tuned Oscillator Adjustments
DACS Accuracy Check
3. Connect DVM to and ground lead to
4.
Key in
[SHIFT)
STEP
0 Hz. If using an DVM,
then
If not using an HP DVM, note voltage
indication for reference later.
5.
Key in
STEP SIZE
)
1023
6. If using an HP DVM, voltage indication should typically be
be + 10.230 V If not using an HP DVM, voltage
indication should be + 10.230 V plus the indication
noted in step 4. If voltage is within tolerance, proceed to
next
step. If voltage indication is incorrect, go to Adjustments 18,
Frequency Control Adjustments, and perform YTO and
DAC
adjustments.
7. On the HP press MATH off.
Positive Supply
8.
Key in
&
ENTER FREQUENCY
)
1 MHz,
[
FREQUENCY SPAN
)
1 MHz.
Adjustment
Connect DVM to and ground lead to Al 1 cover.
9. Key in
STEP SIZE
)
12 (CRT annotation should
indicate DACS 12.)
10. Key in (SHIFT) (CRT annotation should indicate
frequency of approximately 28.75 MHz. This corresponds
to a frequency of 57.5 MHz, since
the
counter indication is
divided by two.)
11. Adjust All OFFSET and/or All GAIN for
frequency of 28.750 MHz MHz as indicated by CRT
annotation. See Figure 3-79 for location of adjustment.
A l 1
J N E D O S C I L L A T O R
A l 1
Figure 3-79. Location of 50 MHz Adjustments
12. Note DVM indication for reference later.
13. Connect DVM to (located on All cover).
Adjustments 3-131