superregenerative detectors work well for wide-band signals such as fm, where they perform "slope detection". regenerative detectors work well for narrow-band signals, especially for cw and ssb which need a heterodyne oscillator or bfo. a superregenerative detector does not have a usable heterodyne oscillator – even though the superregen always self-oscillates, so cw (morse code)and ssb (single side band) signals can't be received properly.