A 0/spl deg/-to-180/spl deg/ variable phase shifter using frequency multiplication

A novel variable 0°-to-180° phase shifter operating at baseband frequencies is presented in this work. First, a 90°-phase shift is generated using an RC network. By using vector summation, a variable 0" to 90e phase shift is accomplished using a potentiometer. The signal subsequently enters a multiplier where the waveform is multiplied by itself to generate a signal at twice the frequency and with twice the phase angle. In this manner, the phase shift range is extended from 0° to 180°. A high-pass filter is used io eliminate the DC component of the output signal.