Abstract: Electronic apparatus for receiving amplitude or frequency modulated facsimile signals detects the instantaneous value ( i.e., the amplitude or frequency) of the modulation by a circuit including means detecting the modulation value in each cycle of the signal and producing a gating signal corresponding in duration to the detected modulation value, a generator of clock pulses higher in frequency than the signal, and a modulator responsive to the clock pulse and gating signal to pass a number of clock pulses commensurate with the modulation value to a counter which generates a marking signal commensurate in amplitude to the modulation value for application to a facsimile recorder.

Abstract: An electronic system for processing graphic teletype coded signals or graphic facsimile signals in different modes of frequency modulation comprises two filter channels passing different frequency modulated or keyed bands, two filter channels respectively passing signals from the two bands to a pulse shaper which produces a pulsed signal corresponding to the outputs of the filter channels, and channels respectively coupling the output of one filter channel and of the shaper to a facsimile recorder.