Patent ID: 6014065
Filing Date: 2000-01-11
Classification: H04L

Abstract:
A multi-phase modulator modulating n digital data to be transmitted into a 2.sup.n digital phase modulated signal, comprising:a bandwidth limiting means for limiting the bandwidth of first and second data signal strings respectively;an analog converting means for converting each resulting signal string into an analog signal string after said bandwidth limitation;a low-pass filter means for receiving each resulting analog signal string;a differential amplifying means for setting the amplitude and the offset of each output from said low-pass filter means;a phase shifting means for generating a pair of carrier signals having a 90-degree phase difference by shifting the phase of a base signal by 90 degrees;a phase modulating means for phase-modulating each output of said differential amplifying means with a respective one of said pair of carrier signals;an integrating means for integrating each output of said differential amplifying means;an offset voltage controlling means for controlling an offset voltage of said differential amplifying means according to a value obtained by adding a signal according to each said integration output to a first temperature compensating signal;an integrating means for integrating each input of said phase modulating means and providing an integration output;an amplitude controlling means for controlling the amplitude of the output of said differential amplifying means according to a value obtained by adding a signal according to each said integration output to a second temperature compensating signal;a multiplying means for multiplying one of said pair of carrier signals by the other;a means for generating a voltage according to the frequency of said carrier; anda phase controlling means for controlling the phase shift of said phase shifting means according to said generated voltage, the output of said multiplying means and a third temperature compensating signal.