Junction-transistor circuits for analogue-to-binary code conversion

Abstract

Code ConversionOne of the problems associated with high-speed digital computen is the conversion of analogue information, usually in the form of an angular shaft position or a voltage, into the binary digital code.An important circuit which is used in analogue to digital converters is the voltage comparator, an electrical device which indicates the instant of time an input voltage waveform passes through a predetermined reference level. This paper describes a voltage comparator which uses a junction transistor and a silicon diode. The comparator circuit is essentially a blocking oscillator which generates a sharp output pulse when the input waveform passes through the reference level. By taking advantage of the special properties of the semiconductor devices, the comparator can be designed to have an accuracy of f 5 millivolts throughout a temperature range of 20°C to 4OO.C.A theoretical analysis of the comparator is given with particular emphasis placed on accuracy and switching speed. I t is shown that by preceding the voltage comparator with a transistor dc summing ' ..amplifier. the reference level for the comparator may be adjustedx , -r a range of f 25 volts.-1 8 -

A Harmonic Analysis of Saturation Recording in a Magnetic Medium

“…The transition write circuit. The constant K, a function of the head core length of magnetization is equal to the average dynamic geometry and the physical dimensions of the pole gap, is transition length bd with a lower limit imposed by the determined by measuring the inductance of the write coil static transition length bs where at a particular frequency, say 1000 cps, and by inserting the measured inductance and the appropriate value of the b = bd bd»>> bs (12) permeability into (17). b = b,, bd <K b8.…”