GB1115998A - - Google Patents

Abstract

1,115,998. Analogue-to-digital converters. COMPAGNIE DES COMPTEURS. 22 Sept., 1965 [28 Sept., 1964], No. 40472/65. Heading G4H. In an analogue-to-digital converter of the kind which produces a timed pulse representing the input analogue and another timed pulse representing the zero value, there are two bi-stables one of which is set by the input value pulse or the other, by the zero pulse, whichever comes first, the bi-stable set preventing the other becoming set. The signals are also each connected to reset the other bi-stable so that the bi-stable that becomes set opens a corresponding gate allowing pulses to pass to a counter. In the form of Fig. 2, temperature is measured by a resistive transducer 7 connected in a bridge 5. The resistor 7 is balanced by variable resistor 8 driven through its whole range by motor 13. A switch 19 gives a pulse Z at the moment resistor 8 corresponds to a temperature of 0‹ C. If the temperature is positive the bridge balances before the zero pulse Z occurs. Detector 6 produces the balance pulse M which sets bi-stable 12 to open gate 22 to allow pulses from alternator 25 and pulse shaper 26 to pass to counter 2. The zero pulse Z resets bi-stable 12 and the counter 2 indicates the value. A bi-stable 35 is set by whichever of the bi-stables 11 and 12 is first set to indicate the sign of the value digitized. In another form the position of a shaft is sensed by a rotating disc having a photo-cell to detect the needle. This corresponds to the timed pulse M. The zero pulse Z is produced as before by a switch.