Modification of the p.r.b.n. crosscorrelation method to correct for the effect of nonlinearity

A 4-level test signal is formed from a 2-level pseudorandom binary sequence by replacing the zero-order hold waveform by a suitably chosen but simple 2-level waveform. By this device, pseudorandom binary crosscorrelation may be made insensitive to a nonlinear input-output path formed from a zero-memory nonlinearity followed by linear dynamics.