HP 8568B, Руководство по испытаниям и регулировке работы, Страница: 235 / 313

18. Frequency Control Adjustments
Full Sweep
11. Repeat Start-Up Time Measurement procedure in step 8 and step 9
Adjustment
for
(
SWEEP TIME
)
of 20 ms. Note value of measurement.
20 ms start-up time:
12. Key in [Shift_) three times and note the CRT annotation.
The annotation should indicate SWEEP GEN measured sweeptime
of (20 ms + start-up time noted in step
ms. If it is not in
determine the difference between this measured sweep time
and the target sweep time of 20 ms + start-up time noted in step
11.
(measured sweep time) (20.00 ms + start-up time) =
13. Adjust FAST for three times the difference; and in
the opposite direction, as noted in step 12. See note below.
Adjust
slightly then key in [SHIFT) and note
new SWEEP GEN measured sweep time as indicated by CRT
annotation. Repeat this process until the 20 ms sweep time is set
to the value calculated in this step.
Note
Adjusting CW increases the sweeptime. If the difference
between the measured 20 ms sweep time and the target sweep time
is less than approximately 0.3 ms, adjust
for the target
sweeptime. Adjusting to 3 times the difference noted in step
12 is only needed if the difference noted in step 12 is greater than 0.3
ms.
14.
YTO and DAC
15.
Adjustments
16.
17.
18.
19.
20.
21.
Repeat the adjustments in step 8 through step 13 until the
measured sweep time at 20 ms is 20 ms plus the Start-Up Time
measured in step 11
ms) and the measured sweep time at 1
is 1.00 plus the start-up time measured in step 8 (50.01 s).
Key in
STEP SIZE
)
0 MHz. The CRT annotation should
indicate
DACS 0.
Connect DVM to and ground to If using an HP
then
If not using an HP DVM, note
voltage indication for reference later.
Key in
STEP
1023 MHz. (CRT annotation may still
indicate
DACS 1023.)
Adjust YTO for DVM indication of + 10.230
V dc. If not using an HP DVM, adjust for specified voltage
plus the DVM indication noted in step 16. See Figure 3-71 for
location of adjustment.
On the HP Press
Connect DVM to
Key in
STEP SIZE
)
0 Hz. If using an HP DVM,
then
If not using an HP DVM, note voltage
indication for reference later.
Adjustments 3-121