Table of Contents
Advertisement
3.3 AC gain
SR446 400 MHz Programmable Gain Preamplifier
10. Connect a BNC cable from the SINE OUT + connector, to the
terminated BNC tee at the "A" input.
11. Press the [Auto Scale] button to increase resolution on the display.
Then slowly adjust the AMPLITUDE knob until the R display
value shows as close to 1.00 mV as possible (must be between
0.990 mV and 1.010 mV).
Now that the lock‑in is prepared, disconnect the BNC cable from the
BNC Tee at the "A" input of the SR865A, and connect that to the INPUT
connector of the SR446. Connect a second BNC cable from the − Out
connector on the SR446 and connect the other end to the BNC Tee on the
SR865A.
Set the SR446 to
,
50 Ω
The following steps are repeated to measure the gain at 0 dB, 20 dB, and
40 dB:
1. Set the SR446 gain to the desired gain (0 dB, 20 dB, or 40 dB).
2. Pres the [Auto Scale] button on the SR865A, and wait at least
1 second.
3. Record the value of R, along with the gain setting.
Now disconnect the BNC cable from the − Out connector and connect it
to the + Out connector. Repeat the measurements for all 3 gains.
− Out
gain
+ 0 dB
+ 20 dB
+ 40 dB
,
, and
.
DC
dB
full BW
+ Out
Spec
0.944 mV to 1.059 mV
9.44 mV to 10.59 mV
94.4 mV to 105.9 mV
23
Advertisement
Table of Contents
