Performance of digital data transmission using single-sideband modulation over nonlinear channels

The performance of single-sideband modulation (SSB) combined with class 4 partial-response signaling (PR4), when applied to a digital microwave radio channel, is evaluated. In particular, the effects of AM/AM and AM/PM conversions caused by the travelling-wave tube (TWT) in the radio transmitter are determined by means of computer simulation. Results are presented in the forms of signal-space effects, eye diagrams, and bit error rates. It is shown that from the point of view of system gain, a linearized TWT performs only marginally better than a TWT with amplitude distortion only.