Keysight U8903A, User Manual

Page: 123 / 167

Audio Analyzer Measurement Functions 5
Keysight U8903A User’s Guide 123
The following figure shows the noise level measurement.
Figure 5-11 Noise level measurement
SMPTE intermodulation distortion (SMPTE IMD)
The SMPTE IMD function provides a measure of the second and third order
intermodulation distortion introduced by the UUT by injecting two pure tones
(tone 1 and tone 2, where tone 1 is at a much lower frequency than tone 2, for
example, 60 Hz and 7 kHz respectively) into the UUT. SMPTE IMD is expressed in
dB (default) or as a percentage.
If tone 1 = f1 and tone 2 = f2, the following harmonics are considered.
– f2 – f1
– f2 + f1
– f2 – 2f1
– f2 + 2f1