TB 9-6625-2212-24
NOTE
To ensure accurate notch depth and shape when checking total
calibration fixture OUTPUT connector must be at least 1 M .
In addition, the load capacitance (instrument connected to the
output) and coaxial cable capacitance must be <75 pF. An 18
inch, 50
coaxial cable has a capacitance of 45 pF; therefore,
keep all cables as short as possible.
8. Attenuator Accuracy
a. Performance Check
(1) Connect calibrator OUTPUT HI and LO to TI INPUT.
(2) Connect TI OUTPUT to true rms voltmeter INPUT.
(3) Position TI controls as listed in (a) through (d) below:
NOTCH FREQUENCY switch to 10 kHz.
(a)
MODE pushbutton to FLAT.
(b)
ATTEN pushbutton to 0 dB.
(c)
ADJUST FOR NULL controls centered.
(d)
(4) Set calibrator frequency to 10 kHz and adjust amplitude output until true rms
voltmeter indicates 10 V ac.
(5) Press ATTEN pushbutton to -60 dB on TI. True rms voltmeter will indicate
between 9.72 and 10.29 mV.
b. Adjustments. No adjustments can be made.
9. Notch Depth Accuracy
a. Performance Check
(1) Connect calibrator OUTPUT HI and LO to TI INPUT.
(2) Connect TI OUTPUT to true rms voltmeter INPUT.
(3) Position controls as listed in (a) through (d) below:
NOTCH FREQUENCY switch to 100 kHz.
(a)
MODE pushbutton to FLAT.
(b)
ATTEN pushbutton to 0 dB.
(c)
ADJUST FOR NULL controls centered.
(d)
(4) Set calibrator frequency to 100 kHz and adjust amplitude output until true rms
voltmeter indicates 10 V ac.
(5) Press TI MODE pushbutton to NOTCH.
(6) Readjust calibrator frequency for a minimum indication on true rms voltmeter.