Figure 5. AM test setup.

TB 9-4931-488-35

(a) FM switch to INT.

(b) MODULATION FREQUENCY RANGE switch to X100.

(14) Connect true rms voltmeter INPUT to A11TP5 (fig. 3) and chassis ground.

Adjust A11R35 (fig. 3) for a 0.840 0.010 V ac true rms voltmeter indication. Record true

rms voltmeter indication (R).

(15) Disconnect true rms voltmeter from A11TP5 (fig. 3) and connect to A11TP3 (fig.

3). True rms voltmeter will indicate within 0.005 V ac of value recorded in (14) above.

(16) While observing true rms voltmeter, slowly vary modulation frequency from 20

Hz to 100 kHz. True rms voltmeter will indicate within 0.025 V ac of value recorded in

(14) above.

(17) Repeat technique of (16) for 100 to 600 kHz. True rms voltmeter will indicate

within 0.050 V ac of value recorded in (14) above.

(18) Set MODULATION FREQUENCY RANGE switch to X3K and adjust

MODULATION FREQUENCY vernier dial to 20.

(19) Disconnect frequency counter and true rms voltmeter from TI. Connect true rms

voltmeter to AM OUTPUT, using 600 Ω termination. Adjust A11R40 (fig. 3) for 3.10 0.03

V ac true rms voltmeter indication (R).

(20) Disconnect equipment setup.

15. AM Sensitivity, Accuracy, and Distortion (All Models Except Those Containing

Option 004)

a. Performance Check

(1) Connect equipment as shown in figure 5.

Figure 5. AM test setup.