PSK to ASK converter for RF digital communications

This work presents a new circuit for the conversion of Binary Phase Shift Keying signals (BPSK) into Amplitude Shift Keying signals (ASK). The basic principles of the conversion method are the super harmonic injection of oscillator circuits and interference phenomena. The first one is used to synchronize the oscillators while the second is used to generate an amplitude interference pattern that reproduces the original phase modulation. When combined with an envelope detector, the proposed circuit allows the coherent demodulation of BPSK signals without need of carrier recovery system. Two prototypes of the converter have been implemented. The first one is a hybrid version working in the 300-400 MHz frequency range. The second has been implemented using Multi Chip Module (MCM) technology, and is intended for working in the range of 1.8-2.0 GHz. The time response of the converter to phase changes of the input signal is about 100 ns for the hybrid version and scales down to about 15 ns for the MCM version, giving upper limits for the modulation rate of about 5 Mbits/s and 30 Mbits/s, respectively.