HF input/output circuits for radio communications receiver/emitter

摘要

The output circuit (1) of a radio emitter includes a mixer (10) in series with a band pass filter (11) and an amplifier (12). The emitter generates a HF digital signal using quadrature amplitude modulation. The mixer receivers an intermediate frequency signal at its input (101). The output circuit includes two frequency doubling modules (151,152) connected between a local oscillator (16) and a second input (102) of the mixer. The oscillator includes bipolar transistors thus reducing phase noise.