Showing papers on "Crystal oven published in 1969"

Frequency modulated solid state crystal oscillator providing a plurality of center frequencies

Abstract: Frequency modulated, solid state oscillator which oscillates at any one of a plurality of center frequencies in response to the positioning of a selector switch that connects a selected center frequency determining circuit to the oscillator. Each of the center frequency determining circuits includes a crystal operating in its series resonant mode, an inductor for tuning, and a resistor for suppressing undesirable crystal operation. Frequency modulation is accomplished by impressing a modulating voltage across a varactor included in the frequency control circuit of the oscillator to thereby change its capacitance and consequently change the frequency of oscillation.

Beat frequency generator using two oscillators controlled by a multiresonator crystal

Abstract: The unique properties of a monolithic crystal filter are turned to account in a low-frequency crystal oscillator system. Each of two different relatively high-frequency signals is generated by a respective crystal controlled oscillator. The oscillators share a common crystal wafer to which each is connected by a respective pair of electrodes. The relatively low beat frequency signal or difference frequency of the oscillators is extracted by a third set of electrodes mounted on the crystal between the electrode pairs connected to the oscillators.

A Digital Frequency Synthesizer for an AM and FM Receiver

Abstract: This paper describes the design of a relatively economical, single crystal, frequency synthesizer that generates the required local oscillator frequencies for an AM and FM broadcast receiver. Selection of a station is accomplished by positioning switches to indicate the station's frequency. Fine tuning is not necessary. The receiver will not (for all practical purposes) drift, because the local oscillator frequency is crystal controlled. Low cost medium scale integrated circuits (MSI) are the building block of this synthesizer.

Frequency modulated crystal controlled oscillator operable at a plurality of temperature compensated center frequencies

Abstract: A frequency modulated, solid state, crystal controlled oscillator, including a voltage variable capacitor, for use in portable transmitters wherein it is desired to operate at a plurality of center frequencies that are stable with temperature change. Any one of a plurality of center frequency determining circuits, each including a crystal operating in its parallel resonant mode, can be selected to determine a desired center frequency. Each crystal is connected in parallel with a temperature compensating network. The biasing point of the voltage variable capacitor, the net inductance of a circuit which applies the modulating voltage thereto are selected to cause the nonlinear characteristics of the crystal and voltage variable capacitor to counterbalance each other so that linear modulation is attained.

Linear voltage controlled crystal oscillators

Abstract: A LINEAR VOLTAGE CONTROLLED CRYSTAL OSCILLATOR HAVING AN AMPLIFIER VARIABLE VOLTAGE FEEDBACK CIRCUIT WITH INDUCTORS, CAPACITORS, AND VARACTORS PRODUCING A VARACTOR NETWORK IN SERIES WITH A CRYSTAL AND INDUCTANCE NETWORK THAT PROVIDE CIRCUIT OSCILLATION WHERE THE PHASE SHIFT THROUGH THE FEEDBACK CIRCUIT IS ZERO, OR AT A FREQUENCY WHERE THE REACTANCE OF THE INDUCTANCE-CAPACITANCE NETWORK CANCELS THE REACTANCE OF THE CRYSTAL NETWORK, WHICH VARACTOR NETWORK IS EASY TO ALIGN TO PROVIDE A LINEAR REACTANCE-VOLTAGE RELATION.

Wide deviation voltage controlled crystal oscillator with temperature compensation

Abstract: A wide deviation voltage controlled oscillator having a tunable crystal filter utilizing a negative temperature coefficient coupling capacitance to produce a linear frequency change with any temperature change and a correcting diode controlled tuning voltage which is also a linear function of temperature to compensate for the linear frequency change and to automatically maintain frequency stability over a wide range of ambient temperatures

A method of measuring small frequency change and its application to two methods of thin film thickness measurement

Abstract: A method of measuring small frequency change is described which utilizes an oscillator whose resonant frequency can be controlled by a biased varactor diode. A phase comparator ensures that the voltage across the varactor is that required to make the oscillator frequency identical with the frequency of the source under investigation. Changes in source frequency are then indicated by changes in diode bias. The method has been used to measure film thickness with the resonant quartz crystal and the stylus profile monitor.

Transistor crystal oscillator operable at a subharmonic frequency of the crystal

Abstract: A transistor oscillator has a piezoelectric crystal vibrator incorporated therein for the stabilization of the oscillation frequency and for producing an oscillator which may oscillate with a subharmonic of said crystal vibrator and with a middle wave range frequency.

Technique for improving the frequency/temperature characteristics of 3cm-band Gunn oscillators

Abstract: A Gunn oscillator was used to stabilise another by injection locking. Over an ambient temperature range of +50 to −20°C, the frequency drift of −0.46 MHz/degC was reduced to +1.4 kHz/degC. The practical limit to the stability is set by changes in the pulling of the control-source frequency, but some improvement is possible by increasing the isolation between the oscillators.