Sangamo Weston, Inc.

Bruce E Randall

Jay K Marshall

Philip M Holberton

A charge balance voltage-to-frequency converter utilizes CMOS circuitry to provide a digital pulse output proportional to an analog input signal. The converter approaches a desired charge balance by cycling between a charging and a discharging state. A clock signal provided by a stable oscillator is applied to a clock input of a CMOS D-type flip-flop. The analog input signal effectively is fed to a non-inverting input of an integrating amplifier. The output of the integrating amplifier is fed to the D input of the flip-flop, which input has a threshold level. The Q output of the flip-flop is connected via a voltage divider to an inverting input of the integrating amplifier. This configuration eliminates the need for a dual polarity power supply. When the output of the integrating amplifier rises above the threshold level of the D input, on the next rising edge of the clock signal, the flip-flop sends feedback pulses to the inverting input, thus beginning the discharge state. Each feedback pulse causes the integrating amplifier to discharge a predetermined amount. When the output of the integrating amplifier falls below the D input threshold level, feedback pulses are inhibited, and the charging state begins again. The output pulses from the flip-flop, when accumulated over a period of time, represent the charge required to balance the charge provided by the input signal. The feedback pulses are summed by an accumulator to provide an indication of the converter input.

Charge balance voltage-to-frequency converter utilizing CMOS circuitry

A magnetic circuit, such as used in a magnetic recording head, or with a Hall-effect device, is biased by applying signals having noise-like properties to the magnetic circuit. Since the biasing signals will be effectively uncorrelated with other signals being applied to the magnetic circuit, the biasing signals cannot introduce an offset in the applied signals which might otherwise cause distortion. In addition, the spectrum of the biasing signals is broadband and of low amplitude. As a result, the biasing signals are unlikely to cause interference with other nearby electrical components.

Biasing for magnetic circuits

A system for measuring power in an electrical distribution circuit having at least three wires includes a Hall-effect generator directly coupled to one of the live wires of the circuit and current transformers coupled to the other live wires of the circuit. The output of each current transformer is magnetically linked to the Hall-effect generator. The excitation current for the Hall-effect generator is derived from the line potential between the live wires. The Hall-effect generator acts to produce an output whose magnitude is directly proportional to the product of the vector sums of the currents flowing in the live wires and the potential between the live wires. This power indicative output may be accumulated to produce an indication of energy consumed by a load connected to the live wires. A high frequency A.C. bias is applied to the Hall generator in order to linearize the output of the generator.

Power measurement in an electrical distribution system having three or

A gain switching apparatus for a signal is controlled by a switching function formed as a function of the signal. The apparatus is provided with a circuit for reducing errors due to common frequency components in the switching function and in the signal being switched thereby. In order to reduce DC error resulting from multiplication of the switching function by a parameter representing the switched signal, the common frequency component of the switching function is substantially eliminated and replaced by a component at a frequency which is a multiple of the common frequency. A simplified logic circuit is provided to perform the frequency multiplication and the resultant error reduction.

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Alpharetta, GA, United States of America

Bruce E Randall