AN UPCONVERTER

摘要

An upconverter receives an intermediate frequency (IF) modulated signal on a port (5) and a local oscillator carrier signal at a port (6). A comb generator (13-15) generates a comb-like waveform from the carrier signal, the waveform having a peak for each of a number of multiples of the carrier fundamental. A bandpass filter (16) selects one of the comb peaks and there is further multiplication at a quadrupler (20). The modulated signal (IF) and the multiplied carrier are mixed in a mixer (23) to provide a high frequency upper sideband (LO + IF) output. The output is transmitted in a waveguide (7) which is integral with the casing (2, 3) and which performs high frequency filtering by virtue of its shape.