TM 11-6625-596-45
Figure 6-4. Hand generator test setup.
6-18.
Dial Speed Test
Electric Co. 640AA condenser microphone, or equal,
shall be used for measuring sound pressure. It shall be
a.
Set NOISE GENERATOR switch 1A4S3 to
calibrated by the reciprocity method in accordance with
LOAD.
A. S. A. Standard Z24.4 " ressure Calibration of
P
Laboratory Standard Pressure Microphones."
b. Connect Telephone Set TA-236/FT linesjL1
(2) Audio oscillator. The audio oscillator
and L2 to the corresponding terminals on the TS-716/U
shall have a frequency range of at least 100 to 10, 000
front panel.
Hertz, shall have a high degree of stability in both output
voltage and frequency, and shall have a Waveform
c.
Depress DIAL SPEED button 1A4S6M.
distortion of less than 2 percent.
(3) Vacuum-tube voltmeter. The vacuum-
d. Adjust DIAL SPEED CALIBRATE control
tube voItmeters used must have flat frequency re-
1A4R17 for a CAL line reading on meter 1A4M1.
sponse (+ dB) from at least 100 to 10, 000 Hertz and
must be capable of measuring voltage from 0.001 rms
e. Press TEST button 1A4S5A and, with the
to 100 volts or more.
free hand, dial 0 (operator). Meter 1A4M1 shall read in
(4) Microphone preamplifier. The micro-
the green area.
phone preamplifier shall have a flat response (+1 dB)
over a frequency range of at least 100 to 10, 000 Hertz,
6-19.
Dial Percent Break Test
shall have a high degree of stability, and shall have
distortion of less than 2 percent.
a. With Telephone Set TA-236/FT connected
as in paragraph 6-18b, depress DIAL BREAK button
b.
Connect the equipment as shown in figure
1A4S6L.
6-5.
b. Adjust DIAL BREAK CALIBRATE control
1A4R18 for a CAL line reading on meter 1A4M1.
test frequency to read 0.96 volt rms as measured by the
vtvm.
c. Press TEST button 1A4S5A and, with the
free hand, dial 0 (operator). Meter 1A4M1 shall read in
d. Data shall be taken in 100-Hertz
the green area.
increments from 300 Hertz to 1, 000 Hertz, and in 250-
Hertz increments from 1, 000 Hertz to 5, 100 Hertz.
6-20.
Driver Frequency Response Test
e. The data obtained in d above n;ust fall
a. Test Equipment. The test equipment used
within the limits of +3 dB on a rising slope of 1-dB-per-
for the response test shall meet the following
octave zero reference centered at 1, 000 Hertz. The
requirements:
output of the driver unit at 1, 000 Hertz shall not
(1) Calibrating microphone. A Western
6-6
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