TB 9-6625-862-24
Figure 3. Test instrument - (TS-421C/U and model F370A).
9. Output Distortion
a. Performance Check
(1) Adjust AMPLITUDE (OUTPUT) control to minimum.
(2) Connect OUTPUT connector to audio analyzer connector.
(3) LOAD switch to ON.
(4) Set FREQUENCY RANGE switch to X10 and turn FREQUENCY dial to 50.
(5) Adjust AMPLITUDE (OUTPUT) control for a + 37dB indication on upper scale
of OUTPUT LEVEL meter. Audio analyzer will indicate less than one percent distortion.
(6) Repeat technique of (4) and (5) above, using FREQUENCY RANGE switch and
FREQUENCY dial settings listed in table 5. Audio analyzer will indicate less than one
percent distortion.