Preamp Connector - Stanford Research Systems SR830 Manual

Rear Panel
MONITOR OUT
TRIG IN
TTL OUT

PREAMP CONNECTOR

These outputs are affected by the X and Y offsets and expands. The
actual outputs are
X Output = (X/sensitivity - offset)xExpandx10V
Y Output = (Y/sensitivity - offset)xExpandx10V
where the offset is a percentage of full scale and the expand is an integer
from 1, 10 or 100. The offsets and expand are set from the front panel.
This BNC provides a buffered output from the signal amplifiers and prefil-
ters. This is the signal just before the A/D converter and PSD. The output
impedance is <1Ω and the output current is limited to 10 mA.
The gain from the signal input to the monitor output is the overall gain
minus the dynamic reserve minus 3dB. The overall gain is 10V divided
by the sensitivity. The actual dynamic reserve is specified in the descrip-
tion of the [Reserve] key. For example, if the sensitivity is 10 mV, the
gain is 60dB. If the dynamic reserve is 20dB, then the gain from the input
to the monitor output is 60-20-3=37dB or a gain of 71. A 10 mV (rms)
input will result in a .7 Vrms or1 Vpk output. The gain is only accurate to
about 1.5dB or 20%.
This output is useful for determining the cause of input overloads and the
effects of prefiltering. However, because the analog gain never exceeds
2000, very small signals may not be amplified enough to viewed at the
monitor output.
This TTL input may be used to trigger stored data samples and/or to start
data acquisition. If Trigger Start is selected, then a rising edge will start
data storage. If the sample rate is also Trigger, then samples are record-
ed at every subsequent trigger. (The first trigger starts the scan and
takes the first data point, subsequent triggers record the rest of the data
points.) When the sample rate is set to Trigger, samples are recorded
whenever there is a rising edge at the Trigger input. The maximum
sample rate is 512 Hz. Data storage is available through the computer
interface only.
This output is the TTL sync output for the internal oscillator. The output is
a square wave whose edges are linked to the sine wave zero crossings.
This is useful when the sine output amplitude is small and a synchronous
trigger is required (to a scope for example). This output is active even
when locked to an external reference.
This 9 pin "D" connector provides power and control signals to external
preamplifiers such as the SR550 and SR552. The power connections are
described below.
Pin
1
2
6
7
8
4-28
Voltage
+20V
+5V
-20V
Signal Ground
Ground