Stanford Research Systems SR860, Руководство по эксплуатации

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2 Getting Started Chapter 1
SR860 DSP Lock-in Amplifier
SR860 Front Panel
The SR860’s buttons and knobs are mainly used to configure the lock-in measurement,
while the touchscreen is mainly for data display. The touchscreen display is also used for
keypad entry.
Signal Path
The signal path settings configure input BNC’s, input gain, time constant and filters and
the sensitivity. Unlike previous generation lock-ins, the SR860 does not have a dynamic
reserve setting. The input range setting is simply the largest input signal before overload.
It is best to decrease the input range setting as much as possible without overload. This
increases the gain and utilizes more of the A/D converter’s range as indicated by the
signal strength LEDs.
The sensitivity determines the scale factor for the analog outputs (CH1 and CH2) as well
as the numeric readouts and bar graphs. The sensitivity does
not affect the measurement
values, it simply determines how much signal corresponds to a full scale 10V output from
CH1 and CH2 outputs and a 100% bar graph. It also sets the scale for the 5 digit numeric
displays. The sensitivity should be viewed as an output function only.
Reference
The reference settings configure the lock-in reference frequency and source. In addition
to internal and external reference, the SR860 includes dual reference (detect at |f
int
−
f
ext
|)
and chop (lock an SR540 chopper TO the SR860 f
int
) modes.
The SR860 can be synchronized to an external 10 MHz frequency reference (from
another SR860 or other source). This allows multiple SR860’s to run in phase sync with
each other in internal reference mode.