Rca Inc.

Kenneth Charles Adam

Charles A Clark, Jr

Finis C Easter

Robert Alan Holt

An analog-to-digital converter of the type using a plurality of voltage comparators, each, in response to an applied reference voltage and an analog voltage to be digitized, producing one of two logic signals depending on which of the applied voltages is the greater includes apparatus for altering the reference voltages on some but not all the comparators as a function of time in response to a control signal. In one embodiment, each of the altered reference voltages is limited to some preselected differential relative to that applied to one of the comparators which does not have its reference voltage altered as a function of time. In another embodiment, that one comparator has its reference voltage altered as a function of ratio of the time it produces one of the two logic signals relative to the other.

Analog-to-digital circuit with adjustable sensitivity

A control transistor in the over-current protection circuitry of a voltage regulator is connected in a regenerative latch circuit with a complementary-conductivity auxiliary transistor, whereby conduction once initiated in said control transistor tends to be sustained. This avoids the tendency towards rapid oscillation between shut-down and power-up conditions in the over-current protection circuitry. The regenerative latch circuit loads the capacitor that supplies its sustaining current so heavily that the potential thereacross decays, the decay finally advancing to the point where regeneration halts. The resulting non-conduction of the control transistor permits the voltage regulator to attempt to resume the power-up condition. The present invention is an improvement in such a voltage regulator wherein circuitry is provided for rapidly recharging the capacitor for supplying sustaining current during this attempt. The recurrence of this cycle during short-circuit loading conditions leads to a relaxation oscillator mode of operation with the power-up duty cycle being sufficiently low that the components of the voltage regulator are kept from being damaged by overheating.

Over-current protection circuit for voltage regulator

The collector current of a first transistor serves as the base drive current for a second transistor of opposite conductivity type than the first transistor. When conduction occurs through the collector-to-emitter path of the second transistor, a conducting diode connected between the emitter of the first transistor and the collector of the second transistor clamps this collector to a relatively fixed voltage level referenced to the fixed base voltage of the first transistor. This prevents saturation of the second transistor and thus reduces the 'storage delay', that is the turn-off time delay of the second transistor. In addition, the charge stored at the base electrode of the second transistor is removed when its collector-to-emitter current flow is interrupted to further reduce the turn-off time of this transistor.

Clamping circuit

Signals producing each spot in a digital two-dimensional spot matrix display, such as in a digital weather radar, are compared on a spot-by-spot basis with signals for immediately proceeding and following spots in each dimension. When the preceding and following spots have the same value, the spot being compared is caused to have that same value when displayed. The comparing circuitry may be provided signals from a radar antenna which receives, serially, signals at succeeding range points at a given azimuth and then at the same range points at succeeding azimuths. Signals at each given range at a plurality of succeeding azimuths may be averaged to produce an improved visual display. The compared signals may be further smoothed by averaging signals for succeeding azimuths and displaying the averaged signals alternating with the unaveraged signals.

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Thousand Oaks, CA, United States of America

Kenneth Charles Adam