Specifications

1820/1822 Operator’s Manual
m. Record the result to two decimal places
(±0.xx%) as ’Xl Gain Error’ in the Test
Record.
n.
CHECK -- That the XI GAIN error is less
than ± 1%.
2. Check +10 Attenuator Accuracy.
NOTE
The accuracy of the internal +10 attenuator is not a
warranted specification. However, the attenuator will
be used in the XIO00 gain test where it’s absolute
accuracy will be included in the calculations.
a.
Verify that the measured output voltage is still
the same value as recorded in step l-k.
b. Set the 1820/1822 ATTENUATOR to +10.
c. After the DMM has stabilized, record the
reading as ’Amplifier Output Voltage’ in the
Test Record to 10 laV resolution.
d. Divide the output voltage recorded in step 1-k
by the attenuated output voltage recorded in
step 2-c. Record the result to four digit
resolution in the Test Record. This is the
’Actual Attenuation’.
e.
Divide the attenuation calculated in step 2-d
by 10.0. Subtract the 1.0 from the result and
multiply this number by 100% to get the
attenuation error in percentage.
Error=(Actual Attenuation(StePlo 2-d)-13
xl00%
f. Record this value as ’+10 Attenuator Error’ in
the Test Record.
g. Add the attenuation error recorded in step 2-f
to the X 1 gain error recorded in step l-k. Be
sure to include the signs of the two terms
when performing this addition. Record the
result to two decimal places (±0.xx%) as ’XI
Gain + +10 Attenuation Error’ in the Test
Record.
h. CHECK -- That the combined X1 Gain +10
Attenuation error is less than ± 1%.
4-4
3, Check the Xl0, Xl00 and Xl000 Gain
Accuracy.
NOTE
Because most DMMs do not provide the required
accuracy on lower AC voltage ranges, the check for
XIO, XIO0 and XIO00 Gain Accuracy uses a ratio
technique with an external +10 attenuator. The actual
attenuation of the attenuator is determined using higher
amplitude signals.
i. Disconnect the amplifier output cable and the
precision 50 f2 termination from the BNC to
banana plug adapter on the DMM.
j. Disconnect the sine wave generator output
cable from the +INPUT and remove the 50 f2
termination from the coaxial cable.
k.
Connect one female end of the BNC Tee to
the sine wave generator cable.
1. Connect a 50 f2 + 10 attenuator to the male
end of the BNC Tee followed by a standard
50 f~ termination.
m. Connect another coaxial cable from the
banana plug on the DMM to the other female
end of the BNC Tee.
n. Set the sine wave generator output amplitude
to read 2.00 Vrms ± 50 mV on the DMM.
o. Record the reading to 1 mV resolution as
’Sine Wave Generator Output Voltage’ in the
Test Record.
p.
Remove the DMM cable from the BNC Tee.
q. Connect the 50 if2 termination end of the
termination/attenuator/BNC Tee combination
of the sine wave generator cable to the DMM
banana plug adapter.
r. Record the DMM reading to 100 laV
resolution in the Test Record as ’ Actual
Amplifier Input Voltage’.
(Note: This reading should be approximately
200 mV. If it is not, verify that the in-line
attenuator and termination are installed in the
correct order. The 50 if2 termination should
be closest to the DMM).
s. Divide the DMM reading in step 3-j into the
output amplitude measured in step 3-g. This
is the exact attenuation of the attenuator-
termination combination.
t. Record the result to four digit resolution as ’
Exact Attenuation’ in the Test Record.