Rca Inc.

Other

USA As Represented by Secretary of the Navy

William G McGuffin

William E Barnette

Joseph A Zenel

A stylus position sensor for a video disc player is described. An electrode secured in fixed relation to a movable stylus with respect to the stylus supporting carriage is disposed between first and second electrodes to form first and second variable capacitors therewith. The capacitance of the variable capacitors change in accordance with the motion of the stylus related electrode between the first and second electrodes. First and second varactor diodes are respectively serially connected with the first and second variable capacitors and poled in a complementary manner with respect to each other. The net capacitance at said third electrode comprises the parallel combination of the two respective series combinations of variable capacitor and varactor diode. The capacitance of the variable diodes is modulated by an AC signal potential coupled from a low impedance source through respective coupling capacitances. As the center electrode is displaced from the center position with respect to the first and second electrodes, the net capacitance at the center electrode increases and decreases in phase with the modulating capacitance of the varactor diode connected to the electrode toward which the stylus moved. A capacitance sensitive pickup circuitry converts the net capacitance change to a signal potential for controlling a servo motor to adjust the carriage position.

Position sensor for video disc

In certain video disc systems it is desirable to have a stylus position sensing apparatus. An electrode secured in fixed relation to a movable stylus is disposed between first and second electrodes to form first and second variable capacitors therewith. The capacitance of the variable capacitors change relative to the motion of the stylus related electrode between the first and second electrodes. Complementary signals are applied to the first and second electrodes, which signals are coupled proportional to the respective variable capacitances to the stylus related electrode. The algebraic sum of the signals coupled to the stylus related electrode is indicative of the position of the stylus.

Stylus position sensor for video disc player apparatus

A delta modulation system for generating a digital output signal representative of an analog input signal. The analog input signal is periodically compared to an analog feedback signal to generate the digital output signal. The analog feedback signal is generated from the digital output signal by generating a signal having an amplitude indicative of the absolute value of the derivative of the analog input signal, multiplying such absolute value signal by the digital output signal and integrating the product signal.

Adaptive delta modulation system

A method and device for measuring the length of a root canal of a tooth in which a reference signal obtained by placing an electrode or terminal of an oscillator in the gingival tissue and a signal obtained by inserting an electrode or terminal of an oscillator into the root canal are phase locked and mixed in a product detector to produce an electrical quantity indicative of the length of the root canal.

Method and device for determining the length of a root canal of a tooth

Logic circuit for dividing an input frequency symmetrically by an odd number without producing spurious transients.

Symmetrical odd modulus frequency divider

A counterwound, magnetic core for a towed-cable, helically wound, ELF anta comprising a cylindrical, plastic, center insert, with or without a center conductor, with two strips or sets of strips of magnetic material counterwound about it so that a plurality of good-mechanical-contact, strip, crossover points are formed distributed around the circumference of the insert and down its length. An insulating material is then wrapped around these counterwound strips and a conductor helically wound around that. This design, by providing alternate flux paths down the core via the crossover points provides a lower, core reluctance and, when the core is under stress, provides a flux path that avoids the high-stress regions of the core thus reducing the amount of flux that is stress-modulated. Thus a substantial magnetostrictive noise reduction is obtained.

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Willingboro, NJ, United States of America

William G McGuffin