TB 9-6625-1138-24
(7) Slowly decrease calibrator frequency until TI R.M.S. VOLTS meter indicates -3 dB.
Record frequency counter indication.
(8) Slowly increase calibrator frequency until TI R.M.S. VOLTS meter passes
through reference established in (6) above and decreases on other side to -3 dB. Record
frequency counter indication.
(9) Determine difference between value recorded in (7) and (8) above. Difference
will not exceed 15 ms.
(10) Compute center frequency by adding values recorded in (7) and (8) above and
dividing by 2.
(11) Adjust calibrator frequency to indicate center frequency value calculated in (10)
above, then adjust frequency dial for peak TI meter indication.
(12) Adjust REF ADJ control for 1.0 V indication on TI R.M.S. VOLTS meter
(100 percent).
NOTE
It may be necessary to increase calibrator output for desired
indication.
(13) Increase calibrator frequency until TI R.M.S. VOLTS meter decreases one-half
of one division (one percentage point). Record frequency counter indication.
(14) Decrease calibrator frequency until TI R.M.S. VOLTS meter passes through
reference established in (12) above and decreases on other side by one-half of one division
(one percentage point). Record frequency counter indication.
(15) Determine difference between values recorded in (13) and (14) above. Difference
will be 3 ms or greater.
NOTE
The one percentage points are critical. If difference in (15)
above is less than 3 ms, repeat (11) through (15) above.
(16) Adjust calibrator frequency for a 3.85 ms indication on frequency counter.
(17) Adjust TI FREQUENCY dial (approximately 260 Hz) for peak TI meter
indication.
(18) Repeat (12) above. Record dB value of RANGE (VOLTS) switch indicator. (1 V
used for 0 (zero) dB reference.)
(19) Decrease calibrator frequency until counter indicates 5.26 ms.
Maintain a
constant output.
(20) Decrease RANGE (DECIBELS) switch setting by 60 dB. TI meter will indicate
0.1 V or less.
(21) Set RANGE (VOLTS) switch to 3 V.
(22) Repeat (16) through (20) above, except in (18) above, increase calibrator
frequency to 3.03 ms.
b. Adjustments. No adjustments can be made.
10
