Rca Inc.

Bortolo M Pradal

Paul L Buess

An overtone oscillator of the feedback type is provided by a transistor, a crystal resonant at a fundamental frequency and higher odd overtone frequencies, and a feedback circuit that includes the crystal, a second transistor connected in cascade with the first transistor and an RC network. This feedback circuit provides the correct phase shift to achieve and sustain oscillations at the desired overtone frequency.

Crystal overtone oscillator using cascade connected transistors

An audio processor for use in an angular modulation transmitter for performing pre-emphasizing, limiting, and low pass filtering functions. Novel pre-emphasis, limiter and low pass filter stages are disclosed.

Audio signal processor

A high signal-to-noise crystal oscillator is provided, including a transistor and a crystal coupled across the input thereof. The oscillator further includes series connected capacitors coupled across the crystal and between the base electrode of the transistor and reference potential with the emitter coupled to the junction of said series connected capacitors. The value of the series connected capacitor is selected to be such that the ratio of the total capacitance between the emitter to ground to the total capacitance between the base and emitter electrodes is on the order of 5.4 to 1 to 3.9 to 1.

High signal-to-noise ratio negative resistance crystal oscillator

A direct FM modulator includes an oscillator comprising a current conducting device providing amplification to sustain oscillations and a frequency determining circuit connected thereto for controlling the frequency of oscillation. The frequency determining circuit includes a piezoelectric element in series with a voltage variable capacitance and an adjustable capacitance coupled across this series combination. The capacitance of the voltage variable capacitance is changed by a modulating voltage to provide frequency deviation about the center frequency of oscillation. A frequency linearization of the crystal oscillator is provided by a selected value of capacitance coupled across the varactor and the capacitance value of the adjustable capacitance such that the frequency deviation vs. voltage is maximum at the initial reference bias voltage and is symmetrical about this reference bias.

Frequency linearization and sensitivity equalization of a frequency

A network for temperature compensation of a crystal oscillator over an extended temperature range encompassing two points of inflection of the drift characteristic of an AT cut crystal. The oscillator is of the type having, in loop connection, an AT cut quartz crystal and a voltage variable capacitance device. The compensation network utilizes a three resistor, three thermistor electrical network for generating a temperature dependent bias voltage applied to the variable capacitance device to compensate for changes in the self-resonant frequency of the crystal due to temperature variation. A method for determining the component values for the compensation network is also disclosed.

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Pittsburgh, PA, United States of America

Bortolo M Pradal