Ectron 560H, Инструкция по эксплуатации

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Model 560H Calibration and Maintenance
GAIN CALIBRATION (FIGURE 7-1 )
1. Connect the amplifier as shown in
Figure 7-1, but without jumper J1.
2. Set all switches to 1.
3. Set the amplifier gain switch to 1000 and the
vernier switch out.
4. Center the trace on the oscilloscope using the
vertical position control.
5. Adjust the voltage divider R2 to .001000.
6. Set S1 to 2.
7. Adjust R23 until the oscilloscope trace is
centered.
8. Return all switches to Position 1.
TEST PROCEDURES
The following test procedure describes the meth-
ods currently used at Ectron to test Model 560H.
The procedure consists of comparing the amplifier
output with an input signal on an oscilloscope
using the differential (A-B) input. Using high
oscilloscope sensitivity, the deviation between
input and output can be easily measured. A
precision divider is used at the input so that the
amplifier output can be exactly equal to the signal
applied to the divider. The basic setup is shown in
Figure 7-1. In duplicating or simulating this
procedure, considerable attention should be given
to proper shielding. A millivolt nullmeter may be
used instead of the oscilloscope to make the differ-
ential measurements.
Differential measurement offers several advantages
over the usual procedures that incorporate digital
voltmeters or other input-output comparison meth-
ods. For instance, to measure linearity the differen-
tial measurement requires only that a signal volt-
age be varied from zero to full scale (usually by a
potentiometer) while the deviation on the oscillo-
scope is observed (0.005% measurements are
easily made with a simple filter). Other methods of
measuring linearity offer many difficulties, includ-
ing accounting for the inaccuracies of the instru-
mentation.
1. Refer to TEST EQUIPMENT REQUIRED
on Page 7-1.
2. Perform the preliminary adjustments outlined
on Page 7-1.
3. Set all switches to Position 1 at the start of
each test unless otherwise specified.
4. Remove jumper J1 unless otherwise
specified.
GAIN ACCURACY (FIGURE 7-1)
1. Adjust the amplifier to the gain position to be
verified. Set the gain vernier switch to out.
2. Adjust the precision divider R2 to the
reciprocal of the gain in step 1.
3. Center the trace on the oscilloscope using the
vertical positioning control.
4. Set S1 to 2.
5. The gain error in percent is the deviation in
volts multiplied by 10.
7-3
Figure 7-2: Test Setup for Frequency Response