Intermodulation Distortion Standards

Several standards define IMD measurements. These standards are best used depending on the type of intermodulation distortion you are trying to capture or similar.

The following table lists two standards and their associated test signals and typical use cases.

Table 13. IMD Standard Test Signals and Typical Use Cases
IMD Standard Test Signal (f1, f2, ratio) Typical Use Cases
SMPTE/DIN

(60, 7000, 4)

(250, 8000, 4)

others

Excite low-frequency distortion mechanisms such as thermal distortion in power amplifiers; disk recording and film
ITU-R (CCIF)

(11000, 12000, 1)

(14000, 15000, 1)

(19000, 20000, 1)

others

 ADC and DAC slope-induced distortion
The frequencies f1 and f2 are the frequencies, in hertz, of the low- and high-frequency tones, respectively. The ratio is the ratio of the amplitude of the low-frequency tone to the amplitude of the high-frequency tone.
Note Do not expect to get the same measured IMD when performing the measurement with different standards. You must specify the test signal used to perform the measurement when you report IMD measurement results.