GB1523883A - Data carrying waveform correction - Google Patents

Abstract

1523883 Pulse shaping and modifying MICRO CONSULTANTS Ltd 22 March 1976 [26 March 1975] 12606/75 Heading H3T In order to recover an original signal (a) Fig. 3, from a signal (b), e.g. from a tape head, in which transitions of the original signal are represented by peaks, signal (b) is applied directly to the non- inverting input of amplifier Al, Fig. 1, and through diodes D1, D2 to the inverting input. The signal at the inverting input is therefore a limited and delayed version of that at the non-inverting input with the result that the output of amplifier Al changes between positive and negative saturation at each peak in the input signal (b). Amplifier A1 may come out of saturation at points of inflexion in the signal (b) and to prevent this falsely operating an output bi-stable G6, G7 the input signal is connected to comparator CA1 having hysteresis which controls the gate circuit G2 to G5 to inhibit the signals from amplifier Al except when the input signal is outside the limits shown in (b) Fig. 3. In a modification, Fig. 5 (not shown), inverter G 1 is replaced by a comparator with hysteresis. Amplifier A 1 may comprise a dual FET differential input stage (TR8), Fig. 4 (not shown), a common emitter second stage (TR6) and an emitter follower output stage.