HP 8340B Manual page 153

5-8. YO LOOP ADJUSTMENTS (Cont'd)
Equipment
Spectrum Analyzer
Spectrum Analyzer
Synthesized Sweeper
Oscilloscope
10:1 Divider Probe
BNC to SMB Snap-On Test Cable (2 required)
50~2 Termination, SMB (f)
Adapters:
APC 3.5 (f) to APC 3.5 (f)
SMA
SMB(m)toSMB(m)
Special Test Fixture
Procedures
YO LOOP RESPONSE ADJUSTMENT
1. Place the OUT in the test position shown in Figure 5-18 and remove the top and bottom covers.
Disconnect the rigid cable (W3) going into the A45 Directional Coupler RF Output through a hole in
the mother board (top of the OUT). Put the YO Loop section in the Service Position. Disconnect all
the cables that connect to A48 and A49 PC boards. Remove the A48 YO Loop Sampler assembly
cover. Connect a 50 Ohm load to W38 at the end that connects to A49J2.
2. Connect the test equipment as shown in Figure 5-18
Set the LINE switch to ON and allow ½ hour warmup.
3. Set the Sweep Generator as follows:
a. Press [INSTR PRESET].
b. Press [CF] (center frequency) [1] [8] [7] [MHz]
c. Press [AF] then enter [2] [0] [0] [MHz]
Press [POWER LEVEL] then enter
d.
e. Press [SWEEP TIME] then enter [1] [0] [msec].
4. Set the oscilloscope controls as follows:
a. Select A vs B mode
b. Set Channel A to 0.05 VOLTS/DIV (with 10:1 Probe)
c. Set Channel B to 1 VOLT/DIV (typically)
d. Select DC coupled on both channels.
5. On the oscilloscope, adjust channel B VOLTS/DIV (used as horizontal gain in A vs. B mode) for a
trace of 10 horizontal divisions on the screen. Adjust the oscilloscope POSITION control to center
the display trace.
6. On the Sweep Generator press [Ml] and enter [1] [6] [0] [MHz]. Press [M2] and enter [2] [1] [0]
[MHz].
7. Adjust A48C1 and A48C2 (Figure 5-19) for a trace on the oscilloscope similar to Figure 5-20. Adjust
for the flattest response from 160 MHz to 210 MHz. The amplitude of the response should be at
least 0.4 Volts peak-to-peak.
5-44 Adjustments
to BNC (f)
(in)
[3] [dBm]
HP 8340B Option 001
HP P/N 85680-60093
(
do not connect the Spectrum Analyzer yet).
HP 8566B
HP 3585A
HP 1741A
HP 100040
HP P/N 1250-0676
HP P/N 5061 -5311
HP P/N 1250-1 200
HP P/N 1250-0669
Fabricated Locally
HP 8340B/41B