Audio Analyzer Measurement Functions 5Keysight U8903A User’s Guide 123The following figure shows the noise level measurement.Figure 5-11 Noise level measurementSMPTE intermodulation distortion (SMPTE IMD)The SMPTE IMD function provides a measure of the second and third orderintermodulation 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, forexample, 60 Hz and 7 kHz respectively) into the UUT. SMPTE IMD is expressed indB (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
