Abstract: A wireless transmitter for PM (phase modulation) signal with a spectrum scrambler for relocation of input spectrum for privacy purposes is comprised of a differential circuit coupled with an input terminal, a spectrum scrambler coupled with output of said differential circuit, and FM (frequency modulation) modulator coupled with output of the spectrum scrambler. Due to the position of the differential circuit before the spectrum scrambler, modulation index of modulated PM signal and/or the frequency band of the modulated PM signal does not increase irrespective of spectrum scrambling.

Abstract: A wireless receiver for a PM (phase modulation) signal with a spectrum scrambling for relocation of speech spectrums for the privacy of purpose is comprised of an antenna for receiving PM modulated signals, an FM demodulator coupled with the antenna, a spectrum de-scrambler connected to output of the FM demodulator, an integration circuit connected to output of said spectrum de-scrambler, and an output terminal coupled with output of the integration circuit. Due to the location of the de-scrambler between the FM demodulator and the integration circuit, a noise spectrum of a reception signal is independent from a design of spectrum scrambling, and an excellent substantial S/N is obtained irrespective of spectrum scrambling.