Stanford Research Systems SR844 User Manual page 26

1-16 Outputs, Offsets and Expands
10 Press CH1 Output to select DISPLAY.
11 Press CH1 Display once to select R(V).
12
Press CH1 Output to select X.
Press CH1 Offset On/Off.
13
14 Press CH1 Offset Modify.
SR844 RF Lock-In Amplifier
This key toggles the CH1 analog output function
between the selected display quantity and X. In
other words, it is possible to have a signal
proportional to X on the analog output while the
display shows R (or some other quantity).
In this case, with the display set to X, X remains the
CH1 analog output quantity and the DVM reads the
same.
This selects R (Volts) as the CH1 display quantity.
Since the CH1 Output is set to DISPLAY, R is now
also the CH1 analog output.
Remember that Xoffset and Yoffset are applied
directly to the demodulator outputs, the value of R
is computed from the offset values of X and Y. The
XYOffs indicator in the CH1 display indicates that
the displayed value is affected by XY offsets.
At the present time, Y is offset to zero and X is
offset to 100 mV. The resultant R is 100 mV and
the CH1 display should read about 0.1 V. Expand is
off since the display quantity R has not been
expanded.
The CH1 analog output should be
(0.1 V/1.0 V - 0.0) × 1 × 10V = 1 V
or 10% of full scale.
The Channel 1 Offset and Expand keys now set the
offset and expand for R.
The CH1 analog output returns to X. The offset and
expand for X are still in effect, even though R is the
displayed quantity. Thus, the DVM reads 10 V.
The CH1 display is unchanged. It still shows R and
0.1 V.
This turns Roffset on. The ROffs indicator within
the CH1 display turns on to show that the displayed
quantity is affected by Roffset. (The XYOffs
indicator within the CH1 display means that XY
offsets are on and also affect the CH1 displayed
quantity.)
The offset of the CH1 display quantity, R(V), is
shown on the Reference display. The reading is in
percent of full scale.