SBASAM0B March 2024 – November 2024 ADS127L18
PRODMIX
Intermodulation distortion (IMD) specifies the mixing effect of two input signals. Signal mixing is caused by ADC nonlinearity resulting in new sum and difference frequencies not contained in the original signal. The IMD second-order terms are (f1 + f2) and (f1 – f2). The IMD third-order terms are (2f1 + f2), (2f1 – f2), (f1 + 2f2), and (f1 – 2f2). Test signals f1 = 9.7kHz and f2 = 10.3kHz are at –6.5dBFS. Equation 12 shows the IMD calculation.
where: