Whats a comb generator?
There’s nothing new or exotic about comb generators, and it’s not hard to imagine what they do. Given an input signal at a relatively-low frequency, and a spectrum analyzer on which to view the output signal, a comb generator’s output consists of a series of harmonics of the input signal that usually stretch well into the gigahertz range. In the time domain, the impression is that of a chaotic yet repetitive waveform composed largely of very fast edges — so fast that an equivalent-time sampling oscilloscope may be needed to appreciate the signal in detail. Above: 1-GHz comb harmonics from hand-wired prototype Left: FR-4 PCB output waveform with 100 MHz input, via Tektronix 7S11 sampler. Photo courtesy of Dennis Tillman What’s awkward about building comb generators and other broadband multipliers is that they’re traditionally based on exotic components such as step-recovery diodes (SRDs) or nonlinear transmission-line devices (NLTLs). SRDs have previously seen application in the Amateu
