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Showing papers on "Frequency drift published in 1970"


Patent
R Brandquist1
16 Feb 1970
TL;DR: In this article, an ultrasonic generator with means for automatically adjusting the oscillation frequency to provide maximum power to the load is presented, which includes a DC-AC converter operating into a resonant circuit that is coupled to the transducer.
Abstract: An ultrasonic generator with means for automatically adjusting the oscillation frequency to provide maximum power to the load. The generator includes a DC-AC converter operating into a resonant circuit that is coupled to the transducer. The converter includes first and second switching devices alternately switched by the frequency modulated output of a frequency controllable oscillator. The modulation frequency is derived across a resistor in the converter circuit and is compared with the modulation frequency in a phase detector to produce a control signal whose polarity is determined by the phase relationship of the compared signals. This control signal controls the oscillator to a frequency at which the transducer delivers maximum power to a load.

35 citations


Patent
28 Oct 1970
TL;DR: In this article, an auxiliary injection phase-locked oscillator is used to provide a signal of sufficient level for operation of a high-frequency discriminator used for noise measurement, and the auxiliary oscillator may additionally be used for calibration of the discriminator preliminary to taking noise measurements.
Abstract: Apparatus is provided for the measurement of frequency modulation noise on the carrier signal output of a low-noise, low-power, high-frequency diode oscillator under test. An auxiliary injection phase-locked oscillator, driven by the oscillator under test, is used to provide a signal of sufficient level for operation of a high-frequency discriminator used for noise measurement. The auxiliary oscillator may additionally be used for calibration of the discriminator preliminary to taking noise measurements.

32 citations


Patent
Karl-Heinz Kupfer1
24 Feb 1970
TL;DR: In this paper, a tuning circuit for a superheterodyne receiver capable of operating within two widely separated frequency ranges by using a single voltage source to bias switching diodes located within electronically tunable frequency selective and oscillator resonant circuits is presented.
Abstract: A tuning circuit particularly for a superheterodyne receiver capable of operating within two widely separated frequency ranges by using a single voltage source to bias switching diodes located within electronically tunable frequency selective and oscillator resonant circuits. For operation within a first frequency range, the single bias source only is connected to the switching diodes. For operation within a second frequency range, the single bias source is disconnected from the switching diodes which are then biased into a blocked condition by a voltage of opposite polarity produced from rectifying the oscillator signal through its switching diode. Tuning within either frequency range is implemented by varying the control voltage for variable capacitance diodes within the frequency selective and oscillator circuits. The local oscillator is provided with an additional resonant circuit tuned to frequencies outside of the two frequency ranges to facilitate the effect of the oscillator when the switching diodes are initially disconnected from the single bias source.

30 citations


Journal ArticleDOI
11 May 1970
TL;DR: In this article, an X-band IMPATT oscillator with a stabilized output power of over 0.5 watt has been developed, which is capable of operation in a frequency range of 10.7 to 11.7 GHz.
Abstract: An X-band IMPATT oscillator having a stabilized output power of over 0.5 watt has been developed. The oscillator consists of a main cavity and a directly coupled reaction-type cavity for stabilization. The oscillator has a frequency stability of 2.6x10/sup -5/ over a temperature variation ranging from 0/spl deg/ to 50/spl deg/C and an rms noise deviation of 15 Hz/1-kHz bandwidth at 500 kHz from the carrier. Design considerations have been made concerning the admittance characteristics of the circuit and of the diode to determine preferable circuit conditions for stabilization. The output-power loss due to the stabilization is as small as 0.4 dB. The oscillator is capable of operation in a frequency range of 10.7 to 11.7 GHz.

22 citations


Patent
27 Feb 1970
TL;DR: In this article, a multichannel navigation receiver with a multi-channel communications transceiver and associated audio system is presented. The system uses analog, digital and heterodyne techniques in a unique combination to accomplish frequency synthesis in simplex transceivers.
Abstract: The subject NAV/COM unit incorporates a multi-channel navigation receiver with a multi-channel communications transceiver and associated audio system. The NAV/COM unit utilizes analog, digital and heterodyne techniques in a unique combination to accomplish frequency synthesis in simplex transceivers. A stabilized master oscillator (SMO) provides frequency generation. A feedback loop is used to slave a voltage controlled oscillator (VCO) frequency to an exact multiple of a crystal controlled reference oscillator frequency. The VCO output frequency is divided by two, mixed with a signal from a high frequency crystal oscillator, divided by n, and compared in frequency and phase with a low frequency crystal oscillator signal. The filtered error signal provides bias to the VCO in such a manner that when the VCO frequency is low, the error signal is a high voltage, and when the VCO frequency is above the desired frequency, the error signal is a low voltage. This error signal drives the VCO towards the selected frequency. When the VCO gets within a certain range of the desired frequency, the loop captures the VCO and pulls it into phase lock. In this condition, the loop establishes an error signal that is essentially a square wave with a frequency equal to that of the reference oscillator. A low pass filter recovers the DC component of the square wave and biases the VCO to maintain the selected frequency output. The square wave duty factor and thus the filtered DC/VCO bias voltage, varies accordingly with selected VCO frequency. The communications section utilizes a two crystal heterodyne oscillator in its associated SMO for two band frequency synthesis.

20 citations


Patent
08 Jun 1970
TL;DR: In this article, an analog voltage signal is converted to a digital output reading by applying it to a variable frequency oscillator, the output frequency of which is proportional to the applied signal.
Abstract: An analog voltage signal is converted to a digital output reading by applying it to a variable frequency oscillator, the output frequency of which is proportional to the applied signal. Initially, the oscillator is set to oscillate at a given reference frequency for zero voltage input signals. The analog signal is then applied to the oscillator for a first given time interval. The output of the oscillator is counted by an up-down counter during this first period to provide a count proportional to the sum of the reference frequency and frequency resulting from the analog signal. The input applied to the oscillator is then changed to either zero volts or the reversed polarity of the analog signal during a second given time interval and the direction of the counter is changed to count the output of the oscillator in a down direction during this second time interval. The resulting counting total after the first and second time intervals registered in the counter is then directly proportional to the value of the analog signal, the count from the reference frequency having been subtracted out over the two time intervals. Any drift effects in the variable frequency oscillator are thus cancelled and a more accurate digital output reading corresponding to the analog signal results. Further features of the method and apparatus contemplate providing an output count in the form of a ratio of a number corresponding to the analog signal and a fixed number provided by a constant input signal so that a scaling factor is provided.

16 citations


Patent
07 Apr 1970
TL;DR: In this paper, a dielectric may be interposed between the antenna and the material to reduce the range of frequency shift of the oscillator, which is indicative of the constant and moisture content of the material.
Abstract: A very high frequency oscillator has an antenna as the frequency determining element. The antenna is immersed in a material having a high ionic conductivity, and the shift in the frequency of the oscillator is measured. The frequency shift is indicative of the dielectric constant and moisture content of the material. A dielectric may be interposed between the antenna and the material to reduce the range of frequency shift of the oscillator.

15 citations


Patent
16 Oct 1970
TL;DR: In this paper, the output frequency of a voltage controlled oscillator is constrained to follow the highest component of significant transitions in an input signal by allowing the input signal to change oscillator-controlling voltages only within a predetermined period after receiving of a signal transition.
Abstract: A voltage controlled oscillator output frequency is constrained to follow the highest component of significant transitions in an input signal by allowing the input signal to change oscillator-controlling voltages only within a predetermined period after receipt of an input signal transition. The output frequency is maintained at its last corrected value between periods of change. The oscillator forms part of a phase lock loop for establishing a clock to recover variable frequency recorded information.

15 citations


Patent
03 Aug 1970
TL;DR: In this paper, a parametric frequency conversion is proposed for a sample of material, such as an alkali vapor, having an energy level system including first and second energy levels with a first transition frequency between them, and a third energy level with a second transition frequency in between the third level and one of the first level.
Abstract: Parametric frequency conversion is effected in a sample of material, such as an alkali vapor, having an energy level system including first and second energy levels with a first transition frequency between them, and a third energy level with a second transition frequency between the third level and one of the first and second levels. The sample of material is disposed in a resonant structure resonating at a frequency substantially equal to the first transition frequency, so as to be within an oscillating electromagnetic field of frequency substantially equal to the first transition frequency, established and maintained by application of a signal to the resonant structure. With a population imbalance between the first and second levels established in the sample as by optical pumping, a carrier beam of energy at a frequency substantially equal to the second transition frequency is directed through the sample. The resonant structure is designed to provide a wavelength within the structure for the field frequency that satisfies a phase-matching condition such that sidebands of the carrier beam are produced by modulation of the index of refraction of the sample, these sidebands differing from the carrier frequency by integral multiples of the field frequency. By appropriate polarizing means, the generated sidebands can be detected, or alternatively, a polarized component of the carrier beam modulated in intensity at the field frequency can be detected. Devices providing this parametric frequency conversion may be arranged to operate as stable, self-oscillating frequency standards or for other purposes such as microwave photon detection.

14 citations


Patent
19 Oct 1970
TL;DR: In this paper, the authors present a low power frequency synthesizer that operates in two time determined modes: a temporary first mode used to initially place the synthesizer at a selected frequency and a second mode used by an analog circuit to sample the voltage controlled oscillator output frequency at regular sampling intervals which are determined by the period of the standard frequency.
Abstract: A stabilized, low power frequency synthesizer operates in two time determined modes. In a temporary first mode used to initially place the synthesizer at a selected frequency, the synthesizer makes use of a standard digital phase locked loop wherein a voltage controlled oscillator output frequency is counted down by a divider, with the divided frequency being compared to a standard frequency in a phase detector to generate an error signal to control the voltage controlled oscillator. In a second mode used to hold the synthesizer at the selected frequency an analog circuit samples the voltage controlled oscillator output frequency at regular sampling intervals which are determined by the period of the standard frequency. These samples comprise a second error signal. The circuit characteristics of the various error signal generating circuits permit the second error signal to be permanently connected to the voltage controlled oscillator while a switching circuit permits connection of the first error signal to the voltage controlled oscillator in accordance with a predetermined timed program when the selected frequency is changed or during initial start up.

14 citations


Journal ArticleDOI
TL;DR: In this paper, a simple modulation technique based on injection phase-locking theory is given for measuring microwave oscillator Q. The measurement procedure is described and typical data are presented for an avalanche-diode oscillator.
Abstract: A simple modulation technique based on injection phase-locking theory is given for measuring microwave oscillator Q. The measurement procedure is described and typical data are presented for an avalanche-diode oscillator.

Patent
08 Oct 1970
TL;DR: In this article, a phase-locked loop is used to generate pulses with precise time-frequency variation with respect to a precise reference frequency source and a voltage-controlled oscillator.
Abstract: A means for generating pulses with precise time-frequency variation embodies a phase locked loop including a precise reference frequency source and a voltage controlled oscillator by means of which an output frequency may be generated precisely in phase and equal in frequency with respect to the precise reference. Control means including a current source the magnitude of which is a predetermined time varying characteristic determines the variation of output frequency from the initial loop controlled value by supplying current, after loop reference disablement, to a capacitor associated with the loop low-pass filter. The voltage thus supplied to the voltage control oscillator effects a predetermined time variation of output frequency during a prescribed output pulse interval.

Patent
22 Jul 1970
TL;DR: In this article, a Doppler effect comparator device comprising means for modulating the optical oscillation produced by the quantum oscillator at a frequency generated by a radio oscillator is presented.
Abstract: The present invention relates to the controlling or piloting of the frequency of a radio oscillator, by a quantum oscillator, or vice-versa The object of the invention is a Doppler effect comparator device comprising means for modulating the optical oscillation produced by the quantum oscillator at a frequency generated by a radio oscillator Interferometric means are provided in order to heterodyne said modulated wave with the modulated wave reflected by a moving obstacle This technique makes it possible to substitute for the comparison of the frequencies received by the comparator, the comparison of the Doppler frequencies which result

Journal ArticleDOI
TL;DR: A large number of auxiliary lines may be generated in the frequency spectrum of an acousto-electric oscillator, if a small r.f. field of a frequency close to the fundamental frequency of the oscillator cavity is superposed on the d.c. field as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this article, the authors introduced equivalent circuits for nonlinear operation of the avalanche transit-time diode at a single frequency and at two harmonically related frequencies and derived parameters that characterize the nonlinear interaction between the diode and the associated microwave circuit.
Abstract: Equivalent circuits are introduced for nonlinear operation of the avalanche transit-time diode at a single frequency and at two harmonically related frequencies. Parameters are derived that characterize the nonlinear interaction between the diode and the associated microwave circuit. Particular attention is devoted to the oscillator, the frequency multiplier, and the frequency divider. For the oscillator, parametric interaction with a harmonic of the desired oscillation frequency is shown to give possibilities of enhancing the output power and of significantly improving the noise performance. An experimental two-frequency oscillator is described that has confirmed the theoretical predictions.

Journal ArticleDOI
TL;DR: In this paper, the characteristics of bias-voltage-controlled AM and FM of a CW Gunn oscillator are reported, and the loaded Q of the microwave oscillator circuit and the microwave impedance level largely govern these characteristics.
Abstract: The characteristics of bias-voltage-controlled AM and FM of a CW Gunn oscillator are reported. It is found that the loaded Q of the microwave oscillator circuit and the microwave impedance level largely govern these characteristics. Modulation mechanisms are discussed. A particular mechanism, due to the nonlinear I-V curve of the device, is shown to lower the oscillating frequency as the bias voltage is increased. Performance of an automatic frequency control loop (AFC) is also described.

Patent
29 Dec 1970
TL;DR: In this article, a variable scan control signal, corresponding to the frequency location of the scan within a given frequency band is applied to a voltage controlled oscillator, which produces an output in the audible range.
Abstract: An audible frequency indicator for use in a radio receiver employing automatic frequency scan tuning. A variable scan control signal, corresponding to the frequency location of the scan within a given frequency band is applied to a voltage controlled oscillator. The voltage controlled oscillator produces an output in the audible range, whose pitch is a function of the frequency location of the scan, and that is terminated when a station is tuned in.

Patent
Joseph F Dienst1
30 Jul 1970
TL;DR: Frequency modulation by varying the intensity of light impinging on a three-terminal GaAs microwave oscillator was studied in this paper, where the frequency was modelled as a Gaussian distribution.
Abstract: Frequency modulation by varying the intensity of light impinging on a three terminal GaAs microwave oscillator.

Patent
R Pincus1
07 Dec 1970
TL;DR: In this paper, a phase and frequency comparator for input signals unavailable simultaneously includes a channel for each of the signals, each channel having a wave shaper for providing a square wave corresponding to the signal, a storage counter driven by the wave shifter, and an oscillator driven by a single oscillator connected in feedback relation to the counter, with means provided for thereupon rendering the oscillator output frequency constant.
Abstract: A phase and frequency comparator for input signals unavailable simultaneously includes a channel for each of the signals, each channel having a wave shaper for providing a square wave corresponding to the signal, a storage counter driven by the wave shaper and an oscillator driven by the storage counter and connected in feedback relation to the counter so that the counter output is zero when the oscillator frequency equals the square wave frequency, with means provided for thereupon rendering the oscillator output frequency constant. The oscillator output is synchronized by the input signal and since the oscillator output is steadily available a conventional phase and/or frequency comparison can be made.

Patent
09 Dec 1970
TL;DR: In this article, a switch connects a selected center frequency determining circuit between a varactor and the active element of an FM modulator, where the capacitance of the varactor is changed by a modulating voltage to provide frequency deviation about the center frequency of oscillation.
Abstract: A multiple center frequency, direct FM modulator includes an oscillator having a plurality of center frequency determining circuits each of which is comprised of a piezoelectric crystal and a warping coil. A switch connects a selected center frequency determining circuit between a varactor and the active element of the oscillator. The capacitance of the varactor is changed by a modulating voltage to provide frequency deviation about the center frequency of oscillation. The crystal has an undesirable tendency to change the deviation corresponding to a given change in varactor capacitance, as the inductance of the warping coil associated therewith is changed. To compensate for this undesirable change in deviation, the values of the components in the frequency controlling circuit of the oscillator are selected such that adjustment of the warping coil causes a change in the variation of equivalent capacitance connected with the crystal so that the frequency deviation corresponding to a modulating voltage of a given amplitude remains constant.

Patent
26 Feb 1970
TL;DR: In this article, a radio frequency transmitter and a receiver having an amplifier having a constant gain portion and a following roll-off above the highest motion Doppler frequency signal to be detected.
Abstract: The illustrated detection apparatus includes a radio frequency transmitter and a receiver having an amplifier which has a constant gain portion and a following roll-off above the highest motion Doppler frequency signal to be detected. The transmitter is a Clapp oscillator. A free running multi-vibrator is coupled into a voltage regulator of the bias supply of the Clapp oscillator to superimpose a supervisory signal which falls within the roll-off portion.

Patent
10 Aug 1970
TL;DR: In this paper, a phase comparator detects the drift and compares the phase thereof with a provided reference signal, the resultant error signal is then fed into the frequency generator to shift the frequency back to its original value.
Abstract: A digitally controlled frequency generator is provided having a selectively variable output frequency with crystal controlled accuracy and stability. Should the desired output frequency drift, however, a phase comparator detects the drift and compares the phase thereof with a provided reference signal. The resultant error signal is then fed into the frequency generator to shift the frequency back to its original value. In addition, should it be desired to change the output frequency of the frequency generator, a new program is applied to a variable program counter which produces an electronic response representative of the new program. This response is sensed by both the phase comparator and an acquisition circuit, the acquisition circuit providing signals to the phase comparator to achieve a "lock-in" of the system at the new desired frequency.

Patent
28 May 1970
TL;DR: In this paper, a variable frequency oscillator is digitally commanded to any one of a large number of frequencies by a system that involves closing a sample data frequency servomechanism loop around a voltage (or current) controlled oscillator.
Abstract: A variable frequency oscillator is digitally commanded to any one of a large number of frequencies by a system that involves closing a sample data frequency servomechanism loop around a voltage (or current) controlled oscillator. In the sample data frequency loop, a phase-locked subharmonic oscillator produces a sampled frequency at a fraction of the oscillator output. This sampled frequency is applied to a logic system that produces a frequency error signal by an arithmetic operation of subtraction and addition. This frequency error signal is then utilized to adjust the controllable oscillator.


Patent
16 Jun 1970
TL;DR: In this article, a switching frequency control loop consisting of an electronically regulated oscillator, a phase discriminator, and a filtered frequency with the frequency of the oscillator is presented.
Abstract: A switching-type matching filter whose switching frequency is extracted from the incident signal, characterized in that it comprises a switching frequency control loop comprising an electronically regulated oscillator, a phase discriminator supplied, on the one hand with a filtered frequency, on the other hand with the frequency of the said oscillator, as well as means for bringing the said oscillator within the coverage range of the phase discriminator and for keeping it within that range if the signal leaving the filter corresponds to predetermined conditions.

Journal ArticleDOI
TL;DR: In this article, a method to obtain a voltage proportional to the average electron density in a gas discharge tube of small diameter is described, which is based on the well known cavity method, and the voltage which controls the oscillator frequency is made to vary linearly with the frequency and hence with the electron density.
Abstract: A method is described to obtain a voltage proportional to the average electron density in a gas discharge tube of small diameter. The method is based on the well known cavity method. The cavity in which the plasma column is placed is inserted in a feedback circuit known as the Pound stabilization circuit, which was originally devised as a means to stabilize the output frequency of a microwave oscillator on the resonant frequency of a cavity. In the method described here, the oscillator frequency is made to follow the cavity resonant frequency. The voltage which controls the oscillator frequency is made to vary linearly with the frequency and hence with the electron density.

Journal ArticleDOI
TL;DR: In this article, experiments undertaken on iron oxide samples (Moxies) at liquid nitrogen temperature were conducted and two terminal and three terminal devices were discussed and a number of applications were demonstrated.
Abstract: We report on experiments undertaken on iron oxide samples (“Moxies”) at liquid nitrogen temperature. The I–V characteristics show a stable negative resistance region. Two terminal and three terminal devices are discussed and a number of applications are demonstrated. These include an oscillator up to 10 MHz, a voltage to frequency converter, a frequency modulator and an amplitude modulator and mixer. Frequency entrainment (“locking”) is demonstrated as well as gated oscillator operation.

Patent
09 Jun 1970
TL;DR: In this paper, a first servo loop responsive to the beat frequency produced in a receiver automatically tunes an oscillator coupled to the input circuit of the receiver to the receiver frequency, while the oscillator automatically tracks this tuning.
Abstract: A first servo loop responsive to the beat frequency produced in a receiver automatically tunes an oscillator coupled to the input circuit of the receiver to the receiver frequency. A second servo loop then tunes the receiver to desired frequencies within the receiver band, while the oscillator automatically tracks this tuning. The second loop may include a comparator for comparing voltages indicative of the frequencies to which it is desired to tune the receiver with a voltage employed for tuning the oscillator.

Patent
07 Apr 1970
TL;DR: In this paper, a high carrier-frequency semiconductor diode oscillator is frequency stabilized against variation in loading and amplitude modulation noise in its output by utilization of a limiter-diode of the PIN type in the output transmission line.
Abstract: A high carrier-frequency semiconductor diode oscillator is frequency stabilized against variation in loading and amplitude modulation noise in its output is reduced by utilization of a limiter-diode of the PIN type in its output transmission line.

Patent
03 Aug 1970
TL;DR: A phase-locked oscillator has an oscillator unit switchable between two frequencies, the switches being controlled by a switching control signal in the form of pulses at a regular repetition rate, said pulses having a duration relative to the repetition period linearly proportional to the amplitude of an integrated phase error signal as mentioned in this paper.
Abstract: A phase-locked oscillator has an oscillator unit switchable between two frequencies, the switches being controlled by a switching control signal in the form of pulses at a regular repetition rate, said pulses having a duration relative to the repetition period linearly proportional to the amplitude of an integrated phase error signal. The oscillator unit is thus switched regularly between its two frequencies, the relative duration of the operation on each frequency being controlled whereby the mean oscillator frequency is controlled to hold the required phase lock, a high degree of linearity between controlling voltage and average output frequency.