Westinghouse Electric Corporation

United States of America as Represented by the Secretary of the Air Force

Steven Morrison

Thomas K Lisle, Jr

Daniel J Healey, Iii

William J Dorman

George A Williams

Clarence C Glover

An improved presettable integrator circuit is disposed in a fast frequency changing phase lock loop for presetting the voltage-controlled oscillator thereof as governed by a preset signal and a pulsed signal generated by a frequency controller. One input of the integrator circuit is coupled to the preset signal, another input is coupled to an integrator control signal, and the output is coupled to the voltage-controlled oscillator for use as a tuning signal thereof. A switch is included in the integrator circuit and is governed in a first state by the pulsed signal to cause the integrator circuit to respond rapidly to an applied preset signal to preset the output signal thereof. In a second state, the switch renders the integrator circuit responsive to an integrator control signal which is selected by a phase lock condition of the loop from either a reference signal or a filtered phase error signal, being coupled to the other input of the integrator circuit. Also disclosed are methods for calibrating the voltage-controlled oscillator of the phase lock loop using the improved presettable integrator circuit when the phase lock loop is selectively governed by one of either a first or second frequency reference source.

Presetting circuit for the voltage-controlled oscillator of a phase lock

Noise induced hunting is eliminated in successive ranged digital/analog converter bias correction circuits by means of a digital hysteresis circuit. The digital hysteresis circuit comprehends a first up/down counter that counts to its extremums from a pre-set intermediate state in response to enable and up/down input signals. For each extremum count an enable output pulse and a reset pulse is generated at the counter output. The enable output pulses are counted by a second up/down counter the output of which drives a digital/analog converter. Each reset pulse resets the first up/down counter to its pre-set state.

Digital hysteresis circuit

An automatic bias adjustment circuit for a successive ranged analog/digital converter (SRADC) that eliminates the need for manual bias adjustments and calibration inputs. The bias correction circuit comprehends dual flip flops that are triggered by selected comparators of the SRADC n bit parallel analog/digital converter. The flip flop output signals control up/down counters whose output bits drive digital/analog converter. The digital/analog converted signals are introduced back into the SRADC analog chain to zero bias errors in a particular sub-range. A disabling circuit prevents operation of the bias adjustment circuits for the first sub-range.

Automatic bias adjustment circuit for a successive ranged analog/digital

A harmonic oscillator coordinate converter in combination with analog and digital circuits is described which may accept signals indicative of a measured angle and of a misalignment angle to provide coordinate conversions of a vector through the measured angle and the misalignment angle during a single angle transformation.

Boresight adjustment for a harmonic oscillator coordinate converter

An electronically controlled coordinate converter for transforming vectors from a first coordinate system to a second coordinate system through an input angle is provided using a harmonic oscillator which is responsive to an oscillation angle control signal having a discontinuity or transition point wherein an incremental change in the input angle at a predetermined value causes a step function in the duration of said oscillation angle control signal. The discontinuity in the oscillation angle control signal is eliminated by control circuits within a selected range of input angles where the error effects due to transformations on either side of the discontinuity are avoided. Another feature of the invention is that the discontinuity in the oscillation angle control signal may be shifted away from or in response to a previous vector transformation having an input angle close to the discontinuity to avoid recurrent vector transformations on either side of the oscillation angle control signal discontinuity due to slight incremental fluctuations in the input angle.

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Baltimore, MD, United States of America

Steven Morrison