DPA-2FL User Manual
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version 1.1
page 8
OFFSET unit
The OFFSET unit consists of (
1
) OFFSET RANGE switch, (
2
) OFFSET
potentiometer and (
3
) ZERO ADJ. trim-pot.
(
1
) OFFSET RANGE switch
Toggle switch for selecting the OFFSET range, x0.1 or x1.
(
2
) OFFSET potentiometer
Potentiometer for compensating a DC OFFSET.
(
3
) ZERO ADJ. trim-pot
Trim-pot for setting the ZERO baseline for the OFFSET.
Trim-pots for compensating amplifier offsets. If the baseline is not zero even if the
input is grounded and the OFFSET potentiometer is in 0 position, this offset can be
compensated using the ZERO ADJ. trim-pot. Compensation procedure:
Set the input switches to OFF to ground the inputs, and set the HIGH PASS
FILTER to 100 Hz.
Set the GAIN range switch to 10 and adjust the baseline to zero using the ZERO
ADJ. trim-pot.
Switch the GAIN factor switch to all positions and readjust to zero if necessary.
Note
: The overall OFFSET compensation is the product of the reading of both controls, range
switch and potentiometer.
Important
: The offset compensation works only if the HIGH PASS FILTER switch is set to
DC. If the HIGH PASS FILTER is used, the OFFSET control is disabled.
(
4
) GAIN switch
6-position rotary switch for setting the amplification factor (GAIN) of the signal
(10, 100, 1k, 2.5k, 5k and 10k).
(
5
) LOW PASS FILTER (Hz) switch
6-position rotary switch for setting the corner frequencies of the single pole
LOW PASS FILTER: 50, 100, 1k, 3k, 5k, 8k Hz.
Note
: By combining HIGH- and LOW PASS FILTER, a filter with bandpass characteristic
can be implemented easily.
