Frequency Discriminator Test-continued

TM 11-5820-509-35

signal generator output frequency to 550 kHz at an

(3) On the test fixture, set switches S1 and

output level of 0.1 volt rms.

S2 to O and OO respectively and then adjust the signal

generator output frequency to 650 kHz and set the ouput

(17) Observe that the multimeter reads not

level to 0.1 volt rms.

less than 4.0 volts dc at jack J5 (fig. 3-14). Then move

the multimeter probe to jack J6 (fig. 3-14) and observe

(4) Observe that the multimeter reads not

that the multimeter reads not less than 1.5 volts dc.

less than 4.0 volts dc at jack J5. Then move the

multimeter probe to jack J6 (fig. 3-14) and observe that

(18) Adjust the signal generator output

the multimeter reads not more than 1.5 volts dc.

frequency to 590 kHz at an output level of 0.1 volt rms

and verify that the conditions recorded in step (17) are

(5) Adjust the signal generator output

obtained.

frequency to 690 kHz at an output level of 0.1 volt rms

and verify that the conditions recorded in step (4) are

(19) Adjust the signal generator output

obtained.

frequency to 610 kHz at an output level of 0.1 volt rms.

(6) Adjust the signal generator output

120) Observe that the multimeter reads not more than

frequency to 710 kHz at an output level of 0.1 volt rms.

1.5 volts dc at jack J5 (fig. 3-14). Then move the

multimeter probe to jack J6 (fig. 3-14) and observe that

(7) Observe that the multimeter reads not

the multimeter reads not less than 4.0 volts dc.

more than 1.5 volts dc at jack J5. Then move the

multimeter probe to jack J6 (fig. 3-14) and observe that

(21) Adjust the signal generator output

the multimeter reads not less than 4.0 volts dc.

frequency to 650 kHz at an output level of 0.1 volt rms

and verify that the conditions recorded in step (20) are

(8) Adjust the signal generator output

obtained.

frequency to 750 kHz at an output level of 0.1 volt rms

and verify that the conditions recorded in step (7) are

(22) Verify that the oscilloscope is connected

obtained.

to jack J4 and that the multimeter reads not less than

4.0 volts dc at jack J6, as in step (20). Then disconnect

(9) Adjust the signal generator output

the signal generator, and observe that the multimeter

frequency to 550 kHz at a level of 0.1 volt rms and note

reading remains essentially unchanged.

that the waveform at jack J4 is slightly clipped.

(23) Adjust the signal generator output

(10) On the test fixture, rotate switch S2 to 6.0

frequency to 490 kHz at an output level of 0.1 volt rms

with S1 remaining at O. Adjust the signal generator

and reconnect the output terminals to the common

output frequency to 600 kHz at an output level of 0.1

junction of T3-C165-R147 (fig. 3-56) in the module

volt rms.

using the 0.01 microfarad capacitor as in step (2).

(11) Observe that the multimeter reads not

(24) Adjust the signal generator output

less than 4.0 volts dc at jack J5 (fig.. 3-14). Then move

frequency toward 600 kHz while observing the

the multimeter probe to jack J6 (fig. 3-14) and observe

multimeter reading. A sharp decrease in the meter

that the multimeter reads not more than 1.5 volts dc.

reading (to approximately 1.5 volts dc) must occur at, or

(12) Adjust the signal generator output

above, 525 kHz.

frequency to 640 kHz at an output level of 0.1 volt rms

(25) Connect the multimeter to jack J5 (fig. 3-

and verify that the conditions recorded in step (11) are

14) and observe that the discriminator output is not less

obtained.

than 4.0 volts dc. Then disconnect the signal generator

(13) Adjust the signal generator output

from the module and observe that the multimeter

frequency to 660 kHz at an output level of 0.1 volt rms.

reading remains essentially unchanged.

(14) Observe that the multimeter reads not

(26) Adjust the signal generator output

more than 1.5 volts dc at jack J5. Then move the

frequency to 810 kHz at an output level of 0.1 volt rms

multimeter probe to jack J6 (fig. 3-14) and observe that

and reconnect the output terminals to the common

the multimeter reads not less than 4.0 volts dc.

junction of T3-C165-R147 (fig. 3-56) in the module

(15) Adjust the signal generator output

using the 0.01 microfarad capacitor as in step (2).

frequency to 700 kHz at an output level of 0.1 volt rms

(27) Adjust the signal generator output

and verify that the conditions recorded in step (14) are

frequency toward 600 kHz while observing the

obtained.

multimeter reading. A sharp decrease in the meter

(16) On the test fixture, rotate switches S1 and

reading (to approximately 1.5 volts dc) must occur at, or

S2 to 9.0 and 9 respectively and adjust the

below, 675 kHz.

6-35