HP 8447D Operation And Service Manual page 15

Model S447D/E/F
Page 11
PERFORMANCE TESTS
55. Gain Flatness, Mean Gain, and Gain Compression (Cont.)
GENERATOR/
SWEEPER
MID! ICI CD
™
o
is
o o o o o ®
AMPLIFIER
UNDER TEST
RMS WIT METER
BNC CABLE ASSY
* I
(STEP 7) | ISTEP 61 |
-p
ADAPTER
SOQTERMINATION^ / BNC CABLE ASSY
BNC TEE
Figure
4.
Flatness and Mean Gain Test Setup: 100 kHz to 10 MHz
8
. Measure, calculate and record amplifier gain at the following frequencies; use the procedures
outlined above.
Frequency Gain
250 ±100 kHz (tune for maximum): ————— dB
100 kHz: —-— dB
9. Select the highest and lowest gains from steps 2, 4, 5, 7, and 8. Subtract the lowest gain from the
highest gain; the result is gain flatness and should be less than 3 dB.
EXAMPLE:
23 dB (highest gain) minus 21.5 dB (lowest gain) = 1.5 dB (gain flatness)
Gain Flatness: ——-.———______ 3 dB
10. Add the highest and lowest gains together and divide by 2; the result is measured mean gain.
EXAMPLE:
ughest gam) plus
vest gain) - 22.25 dB (mean gain)
Mean. Gain, 8447D:
Min. Actual Max.
26 dB...
8447E:
20.5 dB.
23.5 dB
8447F PRE AMP:
26 dB,
8447F POWER AMP: 20.5 dB _
NOTE
Gain rolls off rapidly above 1300 MHz and below 0.1 MHz. If lowest gain was
measured at either of these points, use a frequency counter to monitor the signal
and repeat steps 1 through 10.
23.5 dB