Dicode decoder translating dicode or three-level digital data signal into two level form

Abstract

Abstract 1,130,041. Transistor pulse circuits; data transmission; facsimile transmission. XEROX CORP. 19 Oct., 1965 [25 Nov., 1964], No. 44236/65. Headings H3T, H4F and H4P. Dicode signals (i.e. signals of the form shown in Figs. 2a and 2b) are converted to the original form (Fig. 1) by converting the signals to pushpull form, adding to the neutral terminal of the push-pull circuit a voltage dependent upon the peak amplitude of the signal and feeding the combined voltage to a threshold detector. As shown, the push-pull dicode signals at the secondary of transformer T are combined with a voltage applied to the centre tap equal to half the peak voltage of the positive excursion so that a first threshold circuit SR-3 causes Q6 to conduct when the negative excursion exceeds half its peak amplitude and a second threshold circuit SR-4 causes Q7 to conduct when the inverted positive pulse likewise exceeds the halfpeak value. Differentiating circuits CR-3, R-4 and CR-4, R-5 feed the resulting pulses to respective inputs of a bi-stable circuit Q8-Q9 which thus reproduces the original signal (Fig. 1). The half-amplitude voltage for 16 is derived by a peak-to-peak rectifier C-1, C-2, SR-1, SR-2 and a potentiometer R-1 which divides the rectified voltage by four. The diode signals may be provided by a facsimile transmitter.

Inventors

• 👤 Donald E Mack

Bibliographic Details