Gain; Output Filter - Stanford Research Systems SR446 Operation And Service Manual

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1.2.2 Gain

1.2.3 Output filter

The SR446 can reject a DC bias voltage on the input, as well as unwanted
low frequency signals, by using the AC coupling mode. The cutoff
frequency is around 16 kHz when set to 50 Ω termination and driven
by a 50 Ω source. When the input coupling is set to GND, the amplifier
front‑end circuitry is disconnected from the input BNC and internally
shorted to ground. Note that the input loading at the BNC is not
changed when configured to GND.
Gain of the SR446 is displayed in either
the [Units] button. See the UNIT command (§2.3.6, pg 18).
Gain can be adjusted from +0 dB ( × 1) to +40 dB ( × 100) in 2 dB steps, by
pressing the GAIN or
The full bandwidth ( − 3 dB) of the SR446 is 400 MHz. In many situations,
users may wish to reduce the output bandwidth. This can be helpful
to block unwanted high‑frequency components of an amplified input
signal, as well as to reduce the overall output noise for low‑bandwidth
applications.
The output filter provides three reduced output bandwidth settings,
, , and
200 MHz 100 MHz
setting. The filter setting is selected by pressing OUTPUT
full BW
FILTER or buttons. See the BNDW command (§2.3.7, pg 19).
SR446 400 MHz Programmable Gain Preamplifier
or
dB V/V
. See the GAIN command (§2.3.6, pg 18).
in addition to the full bandwidth
20 MHz
1 Operation
units, selected by