TB 9-6625-2043-35
8. Calibration Factor Control
a. Performance Check
(1) Set CAL FACTOR control against mechanical stop on + (positive) side of CAL
FACTOR dial. Note position of CAL FACTOR control relative to +1 on dial.
(2) Set CAL FACTOR control against mechanical stop on - (negative) side of CAL
FACTOR dial. If position of CAL FACTOR control relative to -1 on dial is not equal and
opposite of that noted in (1) above, perform b (1) below.
(3) Set CAL FACTOR control to -1 dBm.
(4) Zero TI meter as described in paragraph 7 h above.
(5) Set FULL SCALE switch to -30 dBm (OFF-PWR-dBm to dBm).
(6) Connect function/arbitrary generator Output to TI power detector and set
frequency to 200 kHz and set amplitude to minimum setting. (Frequency setting will be
maintained throughout remaining calibration checks.)
(7) Press function/arbitrary generator Output key and increase amplitude until TI
meter indicates -33 dBm.
(8) Set CAL FACTOR control to +1 dBm. If TI does not indicate between -30.9
dBm and -31.1 dBm, perform b (2) below.
(9) Press function/arbitrary generator Output key again to turn off output.
b. Adjustments
(1) Adjust position of CAL FACTOR knob on shaft so that equal and opposite CAL
FACTOR indications are obtained when control is set against stops (R).
(2) Adjust R573 (fig. 1 or 2) for a -31.0 dBm indication on TI meter (R).
9. Electrical Meter Zero
a. Performance Check
(1) Connect RECORDER output (rear panel) to input of true rms voltmeter. For
model 42BD, connect multimeter to RECORDER output (rear panel).
(2) Set CAL FACTOR control to 0 dBm. This CAL FACTOR control setting will
be maintained throughout remaining calibration checks at function/arbitrary generator
frequency of 200 kHz.
(3) Set FULL SCALE switch to -50 dBm (OFF-PWR-dBm switch to PWR).
