TB 9-6625-132-24
11. Sinewave Distortion
a. Performance Check
(1) Connect TI OUTPUT to oscilloscope channel 1 input using a 50 Ω feedthrough
termination.
(2) Set TI controls as indicated in (a) through (i) below.
(a) FREQUENCY Hz
20
102
(b) MULTIPLIER
(c) FREQUENCY VERNIER
fully CW
(d) Waveform pushbutton
(Sine)
(e) VAR SYMM
off
(f) FREE RUN
in
(g) ATTENUATOR
0 dB
(h) AMPL (variable)
centered
(i) OFFSET
off
(3) Set TI AMPL for a 15 V p-p indication on oscilloscope.
(4) Disconnect TI from oscilloscope and connect to audio analyzer. Set audio analyzer to
measure distortion.
(5) Set TI MULTIPLIER to 1. Do not change the AMPL control.
NOTE
For the following check, the TI FREQUENCY Hz control must
be on the calibrated portion of dial. The TI MULTIPLIER
must be on 103 or below for the 20 Hz to 20 kHz check.
(6) Measure TI output distortion at several points over the frequency ranges of 20 Hz to
20 kHz. If audio analyzer does not indicate ≤ 0.25% distortion over the frequency ranges of 20 Hz
to 20 kHz, perform b below.
(7) Measure TI output distortion at several points over the frequency ranges of 20 kHz to
100 kHz. If audio analyzer does not ≤ 0.50% distortion over the frequency ranges of 20 kHz to 100
kHz, perform b below.
(8) Disconnect TI from audio analyzer and feedthrough termination, and connect TI
OUTPUT to spectrum analyzer through a X10 attenuator.
(10) Adjust the TI AMPLITUDE control and the spectrum analyzer controls so that
amplitudes 30 dB or more below the fundamental amplitude are easily viewed on the spectrum
analyzer.
