composite second order (CATV) (CSO)

Composite Second Order(CSO) are intermodulation distortions of second orderharmonics. Similarly, composite third order (CTO) are intermodulation perturbations of third order harmonics.

CSO intermodulations are produced by one or two carrier frequencies subject to second order nonlinearity. With only one carrier frequency, the composite second order corresponds to twice the fundamental frequency. With two carrier frequencies it results from the sum or the difference of the carrier frequencies, whereby one carrier frequency must be larger than the other.

The Composite Second Order plays a role in broadband cable networks and CATV systems, where these intermodulation distortions become noticeable. These distortions are generated by non- linearity of the cable components.