Showing papers on "Frequency multiplier published in 1990"

Multiple-modulator fractional-n divider

Abstract: A fractional-N type frequency synthesizer includes a frequency divider having a selectable integer divide number which is periodically temporarily altered to provide an average rational divide number for the frequency divider. A number of modulator circuits coupled in cascade fashion provide a zero sum modulation signal which varies the value of the frequency divider divisor value such that the net change in divisor value due to the modulation signal is zero thereby reducing phase noise resulting from the temporary altering of the integer divisor value close to the frequency synthesizer carrier frequency.

Broadband frequency doubler for femtosecond pulses

Abstract: A highly efficient frequency doubler is developed for femtosecond pulses. Design aspects of the device are discussed. Doubling bandwidth calculations have shown, that with one millimeter long crystals pulses as short as 10 fs can be frequency doubled. Experimental results testing the doubler with 300 fs, 496 nm pulses are presented showing no spectral narrowing.

Millimeter- and submillimeter-wave multipliers using quantum-barrier-varactor (QBV) diodes

Abstract: Experimental results are presented using quantum-barrier-varactor (QBV) diodes in harmonic multipliers. Output powers and tripler conversion efficiencies of more than 2 mW and 5%, respectively, were achieved between 210 and 280 GHz. In a crude experiment, an efficiency of more than 0.2% for the fifth harmonic was measured at 310 GHz. The values for the QBV diode as a tripler are comparable to state-of-the-art results for Schottky-varactor diode triplers. The experimental results agree well with theoretical calculations. >

Method and apparatus for changing brain wave frequency

Abstract: A method for changing brain wave frequency to a desired frequency determines a current brain wave frequency of a user, generates two frequencies with a frequency difference of a magnitude between that of the current actual brain wave frequency and the desired frequency but always within a predetermined range of the current actual brain wave frequency, and produces an output to the user corresponding to the two frequencies. One apparatus to accomplish the method has a computer processor, a computer memory, EEG electrodes along with an amplifier, a programmable timing generator responsive to the computer processor for generating the two frequencies, audio amplifiers and a beat frequency generator driving a visual frequency amplifier.

Direct conversion receiver with dithering local carrier frequency for detecting transmitted carrier frequency

Abstract: An FSK receiver includes first and second channel paths to which the received FSK signals are applied. Each channel path includes a mixer circuit, a low-pass filter connected to the mixer circuit, and a limiting amplifier connected to the low-pass filter. A voltage-controlled oscillator generates a local carrier and a phase shifter applies its output to the mixer circuits with a 90° phase difference therebetween. A frequency detector is coupled to one of the limiting amplifiers for generating a signal representative of the deviation frequency minus the offset frequency of the received FSK signal. An average circuit detects an average value of the signal from the frequency detector. A comparator circuit detects whether the frequency representative signal lies in or outside of the neighborhood of the average value. A ramp voltage of constant amplitude is periodically generated if the signal is detected as lying outside of the neighborhood and maintained at an instantaneous value if the signal is detected as lying in the neighborhood. The voltage-controlled oscillator is responsive to the ramp generator to control the frequency of the local carrier in search of the transmitted carrier frequency.

Phase-locked loop circuit and method

Abstract: A phase-locked loop circuit and method for producing an output signal which is phase locked with respect to an input signal are disclosed The circuit includes a phase detector responsive to the phase relationship between the input signal and the output signal A controlled signal generator, which includes a voltage controlled oscillator, generates the output signal and includes coarse adjust circuitry and fine adjust circuitry The coarse adjust circuitry causes the frequency of the output signal to fall within one of a selected group of frequency bands in response to the frequency of the input signal Once the coarse adjustment is made, the fine adjust circuitry continuously changes the frequency and phase of the output signal in response to the phase detector so that the output signal will be phase locked to the input signal

Method and apparatus for increasing the high frequency sensitivity response of a sampler frequency converter

Abstract: A method and apparatus comprising a sampler frequency converter having a first and a second diode. A local oscillator having a frequency F LO , a step recovery diode and a balun transformer are used for providing positive and negative sampling pulses to the diodes for sampling an input signal applied to the diodes having a frequency F IN . An output signal is provided by the diodes having a frequency F OUT which is defined by the relationship F OUT |F IN ±N×F LO | where N is an integer harmonic number 1, 2, 3 . . . and the output signal has an amplitude which varies as a function of (sin x)/x where x=F IN . A bandpass filter is provided which is responsive to the output signal for filtering a predetermined band of frequencies therefrom and a bias circuit is provided for forward biasing the diodes so that the frequency F IN of said input signal at which nulls occur in said (sin x)/x relationship occur at a lower frequency after said biasing than before said biasing.

Clock adapter using a phase locked loop configured as a frequency multiplier with a non-integer feedback divider

Abstract: A phase locked loop configured as a frequency multiplier capable of nonintegral feedback path division utilizes a multiphase voltage controlled oscillator (5) which generates a plurality of signals (10a-10f) having a substantially identical frequency but each offset equally from the other by a given phase angle. A commutator (3) selects signals of adjacent phases so as to give the time average output signal (9) a frequency higher or lower than the frequency 10a-10f. Frequency translation is accomplished by periodically selecting signals having a longer or shorter period as desired so that a commutator output signal (9) is delayed or advanced by an appropriate amount. In the preferred embodiment, the phase locked loop is capable of converting a 1.544 MHz signal to a 2.048 MHz signal or vice versa.

Fractional-n frequency synthesizer using delta-sigma modulator in divider control circuit

Abstract: A fractional-N frequency synthesizer having a programmable divider and a control circuit therefor, wherein said control circuit incorporates a digital delta-sigma modulator operating as an interpolator.

High voltage oscilloscope probe with wide frequency response

Abstract: A high voltage probe comprises a standard high frequency coaxial cable terminated in its characteristic impedance through most of the high frequency range, and a circuit of resistors and capacitors that provide a fixed division ratio regardless of the input frequency.

Transponder with reply frequency derived from frequency of received interrogation signal

Abstract: A transponder includes a receiver for receiving a radio interrogation signal. The transponder also includes a phase locked loop decoder for deriving a reference signal from the received interrogation signal, and a radio transmitter for transmitting a transponder reply signal. The phase locked loop has an output which feeds the AC reference signal to the transmitter. The transmitter includes a frequency doubler which generates a transmitter radio frequency at double the frequency of the reference signal. The transmitter radio frequency is therefore controlled by the radio frequency of the interrogation signal. The phase locked loop includes a divide-by-N counter, where N is a predetermined integer parameter. The parameter N determines the derivation of the reference signal frequency from the interrogation signal frequency.

Monolithically realizable harmonic trapping circuit

Abstract: A monolithically realizable harmonic trapping circuit that is a shunt connected series-resonant inductor-capacitor combination which has a resonant frequency designed to coincide with an undesired harmonic frequency of a desired fundamental frequency signal.

Receiver for terrestrial AM and satellite FM-TV broadcasting signals

Abstract: Receiver for terrestrial AM and satellite FM-HF-TV signals in first and second frequency ranges, respectively, of mutually predominantly equal dimensions, which succeed each other in frequency, comprising, arranged one after the others, a HF-AM-FM section (2-6), a mixing circuit (8) common for the AM and FM-TV signals and an IF device (10-20), oscillator mixing signals being applied from a tuning oscillator (9) to that mixing circuit for a frequency conversion of the AM and FM-HF-TV signals into a first AM and an FM intermediate frequency signal, respectively, having a first AM and an FM intermediate frequency, of which at least the first AM intermediate frequency is located above the first frequency region In order to enable a simple and cheap realisation, in which a tuning oscillator having a comparatively narrow-band tuning range can be used, the first AM intermediate frequency is of the order of magnitude of twice the highest frequency of the first frequency range and the FM intermediate frequency is of the order of magnitude of half the lowest frequency of the second frequency range, the IF-device including an AM (13-19) and a FM-IF (10,11) section whose inputs are coupled to an output of the mixing circuit for a separate selection and processing of the first AM and the FM-intermediate frequency signal respectively

Low-parasitic, planar Schottky diodes for millimeter-wave integrated circuits

Abstract: The design and fabrication of air-bridged, ultra-low-capacitance Schottky barrier diodes are described. Mott diodes, for mixer applications, and varactor diodes, for use in frequency multipliers, have been produced simultaneously on epitaxial wafers grown by molecular beam epitaxy. Typical mixer diodes have a nominal anode contact area of 4 mu m/sup 2/ and exhibit a total zero-bias capacitance of 4.0-4.5 fF (including a parasitic capacitance of approximately 1.0 fF) and a series resistance of 6-8 Omega . Diode chips have been incorporated in hybrid integrated circuit (MIC) mixers for 33-50 GHz and 75-110 GHz and an MIC frequency tripler for 90-140 GHz. Fully monolithic (MMIC) subharmonically pumped mixers for 75-110 GHz have also been fabricated and tested. >

Power supply frequency regulating device for vibration wave driven motor

Abstract: A vibration wave driven motor comprise a comparator for comparing a resonance frequency of the motor with a power supply frequency and a frequency setter for setting the power supply frequency according to a predetermined algorithm in response to the output of the comparator. The frequency setter is provided with an algorithm which, if the power supply frequency is identified lower than the resonance frequency by the comparator, brings the power supply frequency toward an optimum frequency through a predetermined frequency higher than the resonance frequency.

Frequency synthesizer PLL having digital and analog phase detectors

Abstract: A frequency synthesizer phase locked loop includes a voltage controlled oscillator (VCO) providing a variable frequency signal, a reference frequency oscillator providing a reference frequency signal, a phase comparison circuit for comparing the phases of the variable frequency and reference frequency signals and providing an output signal to a loop filter, the output of the loop filter providing a frequency control signal to the VCO. The phase comparison circuit includes a digital phase detector providing an output signal on an output line coupled to a charge pump for providing a first output signal to the loop filter; and an analog phase detector including a sample and hold circuit, and a control circuit responsive to the variable and reference frequency signals for providing a signal for sampling to the sample and hold circuit, the sample and hold circuit providing a second output signal to the loop filter. The analog phase detector includes a voltage detection circuit for detecting the voltage level of the signal held by the sample and hold circuit, and for selectively inhibiting the first output signal when the voltage is within predetermined limits.

Birefringent tuning double frequency He-Ne laser.

Abstract: Experimental details are given of a novel, promising kind of double frequency laser—with power output of 0.8–1.4 mW, large frequency difference from 37 MHz to a longitudinal mode interval, and frequency stability of 10−5, and its potential uses are discussed.

Phase-locked loop with pulse-duration modulation fine frequency control

Abstract: A phase-locked loop includes an oscillator controlled by means of a switching network and a microprocessor which generates, in response to the output of a phase detector, two groups of output signals. A first group (Q1 . . . QN) is for adjusting the frequency of the oscillator in steps by selectively switching in frequency determining elements, and a second group (P1 . . . PM) for feeding a pulse duration modulator. The pulse duration modulator produces a control signal for a frequency determining minimum element of the switching network. The control signal has a duty cycle indicative of the frequency determination contribution by the minimum element.

Direct digital synthesizer/direct analog synthesizer hybrid frequency synthesizer

Abstract: A digital/analog hybrid frequency synthesizer having a digital frequency synthesizer for digitally generating an analog output signal of a predetermined frequency within a frequency range of f to f+Δf; an input stage analog frequency synthesizer for, receiving the digital frequency synthesizer output signal and I analog input stage input signals, each input stage input signal separated in frequency from a next one by a frequency increment of Δf wherein a first one and a last one of the input stage input signals are respectively of a frequency of f A and f A +(I-1)Δf, selecting one input stage input signal from the input stage input signals, mixing the selected input stage input signal with the digital frequency synthesizer output signal and providing a resultant input stage output signal; and an output stage analog frequency synthesizer for, receiving the input stage output signal and K analog output stage input signals, each output stage input signal separated in frequency from a next one by a frequency increment of IΔf wherein a first one and a last one of the output stage input signals are respectively of a frequency of f N and f N +(K-1)IΔf, selecting one output stage input signal from the output stage input signals, mixing the selected output stage input signal with the input stage output signal and providing a resultant output stage output signal. Additional intermediate frequency stages may be employed to facilitate greater bandwidth expansion.

A minaturized broad-band MMIC frequency doubler

Abstract: A miniaturized broadband balanced MMIC (monolithic microwave integrated circuit) frequency double, composed of a common-gate FET and a common-source FET directly connected to each drain electrode, has been proposed and demonstrated. The doubler is designed and fabricated as a miniaturized function module using a conventional two-gate FET configuration, active trapping, and active impedance matching. The doubler design has been performed through phase error estimation, gate width optimization, and gate-source voltage optimization. The phase error estimation in a nonlinear condition has eliminated phase error compensation circuits. The fabricated chip size is only 0.5 mm*0.5 mm, which is about 1/10 the area of previously reported doublers. A conversion loss of 8-10 dB, a fundamental frequency suppression better than 17 dB, and an input return loss better than 8 dB are obtained in the output frequency range from 6 to 16 GHz. The broadband doubler as a miniaturized MMIC function module can be applicable to small-size oscillator MMICs and multifunction MMICs. >

Uninterruptible power supply apparatus and isolating method thereof

Abstract: A commercial alternating current power source is provided to a first frequency converting circuit (PC1) through a filter circuit (F) and a reactor (LAC). A high frequency switching power supply circuit (15) of the first frequency converting circuit is switched in response to the commercial alternating current power source to output high frequency power. The high frequency power is transferred to a second frequency converting circuit (PC2) through dielectric materials in capacitors (C1, C2) using electric field thereof as a transfer medium. In the second frequency converting circuit, a rectifying circuit (70) rectifies the high frequency power, so that a charging circuit 72) charges a back-up battery (BT) in response to a rectified output. An inverter 77 included in the second frequency converting circuit is switched to output alternating current power, in response to the output of the first frequency converting circuit when the power source is normal, and in response to the battery when the power source is interrupted, respectively. An isolation barrier 44 of the capacitors isolates the second frequency converting circuit from the first frequency converting circuit, whereby an isolation circuit can be made lighter and more compact.

Laser frequency stabilization

Abstract: In one aspect, frequency fluctuations are stabilized in a laser beam using a frequency stabilization stage that includes a modulator for dithering (i.e., periodically scanning) the frequency of the laser beam, and absorption resonance cell that has a resonance at a predetermined linewidth to which the dithered beam is applied. The output of the cell is synchronously demodulated with respect to the dithering to produce a correction signal that represents the frequency fluctuations with respect to a reference frequency within the absorption linewidth, and the correction signal is used in a configuration which corrects for the frequency fluctuations and produces from the stage a non-dithered, frequency stabilized output. In another aspect, the frequency of the laser beam is controlled using the molecular or atomic resonances of a plurality of successive frequency stabilization stages. Each stage includes an independent control servo loop incorporating a respective absorption resonance cell and constructed to produce frequency correction referenced upon a predetermined resonance of the absorption cell, and the predetermined reference resonances of successive absorption cells have successively narrower linewidths. Each successive frequency stabilization stage, referenced on its predetermined resonance, serves to reduce the range of frequency fluctuations of its output relative to its input.

Variable frequency signal generator

Abstract: A variable frequency signal generator includes a phase locked loop having a variable frequency oscillator (1) which has a control port to which a frequency determining signal is applied, the output of the oscillator being fed via a frequency divider (6) to a phase sensitive detector (7) where it is compared with a reference frequency signal, the result of said comparison being arranged to generate a comparison signal which is fed to a loop filter (9) which is coupled to said control port; and the signal generator including means for applying a frequency control signal thereto comprising a first path being arranged to adjust the division ratio of the frequency divider (6), and a second path including means for combining said frequency control signal and said comparison signal to produce said frequency determining signal; and calibration means (11-14) for adjusting the relative characteristics of said first and second paths to compensate for effects arising from tuning sensitivity dependence on frequency of said variable frequency generator (1).

Control apparatus for vibration driven motor

Abstract: A unit for attenuating frequency components generated in a sideband of a frequency of an AC voltage applied to an electro-mechanical energy conversion element. This attenuation is achieved by modulation performed in a speed control apparatus for a vibration driven motor. The control apparatus includes a filter for cutting frequency components of a smaller frequency difference (fd) or more of an absolute value of a frequency difference between a natural frequency of an n-th order vibration and a natural frequency of an (n-1)th- or (n+1)th-order. A filter output is input to a modulator in a driving circuit, and noise of the vibration driven motor can be greatly reduced.

Frequency modulated phase locked loop with fractional divider and jitter compensation

Abstract: A fractional-N type frequency synthesizer has a voltage controlled oscillator controlled in a phase-locked loop by a divide by N divider and a phase comparator responsive to the divided frequency and to a reference frequency Fr. An accumulator is responsive to the desired fractional part of the N and is clocked by Fr to produce carry signals for producing the required periodic variations in N. A second accumulator produces periodic equal and opposite further variations in N to reduce the magnitude of the error waveform which would be given to the phase-detector output by the variations in n caused by the first accumulator. A digital to analog converter and a differentiating circuit produce a jitter correction signal for reducing residual jitter. A coherent detector detects for the presence of any residual jitter at the control input of the VCO and resulting from the fractional-N control circuit. Any such residual jitter produces a control signal which adjusts the value of the jitter correction signal accordingly. Two-port frequency modulation is produced by an in-band circuit incorporating an integrator and a full band circuit. With no FM input, a counter detects any divergence in output frequency from the desired value and caused by spurious input at the integrator. A resultant control signal offsets any such spurious inputs. The coherent detector detects at the control input of the VCO any component which is coherent with the in band modulation signal and adjusts the full band modulation signal to eliminate this, so that correct FM is produced.

Laser pumped atomic frequency standard with high frequency stability

Abstract: A laser emits a laser beam with a predetermined frequency, serving as pumping light, to a double resonance section. A VCO oscillates a predetermined frequency signal that is the origin of a microwave. An oscillator oscillates a modulation signal and a low frequency signal to be a reference signal for a sync detection. A synthesizer generates a microwave acquired by subjecting the predetermined frequency signal to multiplication and phase modulation in accordance with the predetermined frequency signal and the modulation signal, and applies the microwave to the double resonance section. A photosensor detects a component of the laser beam modulated by the double resonance section. A PSD detects the level and phase of an output signal of the photosensor with the reference signal. A sweep signal generator generates a sweep signal for the microwave. A switch has first and second nodes to be mutually switched from one to the other, and feeds a PSD output back to the VCO when switched to the first node, and supplies the sweep signal to the VCO to permit sweeping of the frequency of the microwave when switched to the second node. An integration processor detects the amount of shift of a microwave resonance frequency according to the PSD output and feeds a laser frequency compensation signal back to the laser, in a state where the switch is set to the second node.

Programmable frequency divider

Abstract: A programmable frequency divider for dividing the frequency of a supplied high-frequency signal directly into a lower frequency includes a plurality of 2-scale-factor prescalers or programmable frequency divider units each capable of being switched between divide-by-2 and divide-by-3 modes. The 2-scale-factor prescalers are connected in cascade for producing an output signal which is frequency-divided at one of multiple division ratios at a time.

PSK signal demodulation system

Abstract: A PSK signal which is subject to frequency fluctuation and noise is demodulated through a quasi-coherent detection process with a fixed local frequency oscillator (5) noise elimination process using a low pass filter (17,18) after frequency adjustment, and a frequency and phase regeneration process using a PLL circuit (20). The PLL circuit (20) is updated by the estimated center frequency of a received signal by using an FFT (fast Fourier transform) circuit (11), a power spectrum means (12,13,14), and a frequency estimation circuit (15) estimating the center frequency based upon the fact that the modulated signal component exists only on a high level portion of the frequency spectrum.

Karman vortex flowmeter with signal waveform shaper circuit

Abstract: A Karman vortex flowmeter which comprises, in addition to a conventional vortex frequency detector for outputting an electrical signal including a vortex frequency signal component, a filter group consisting of a plurality of filters having a gradation of pass bands covering the variation range of the vortex frequency, and a waveform shaper circuit coupled to the output of the filter group for forming a pulse-shaped signal having a frequency equal to the vortex frequency. A filter in the filter group is selectively coupled to the shaper circuit in response to the output frequency thereof. The shaper circuit, on the other hand, holds the peak and the bottom level of the electrical signal; compares them with the positively and the negatively shifted electrical signal, respectively; and sets and resets a flip-flop when the peak and the bottom level cross with the positively and the negatively shifted electrical signal, respectively, the peak and the bottom level being reset after each occurrence of the crossing. The flip-flops outputs a pulse-shaped signal having the vortex frequency even if the electrical signal contains high and low frequency noise components.

Digitizer system with passive pointer

Abstract: A driving grid is driven by an ac signal comprising a carrier frequency modulated by a lower frequency. An untethered, batteryless pointer includes a pick-up coil in a first tuned circuit tuned to the carrier frequency, connected by diodes to a driving coil in a second tuned circuit tuned to the lower modulating frequency. Energy picked up by the first tuned circuit from the driving grid at the carrier frequency drives the second tuned circuit at the modulating frequency. Modulating frequency signals induced in the receiving grid conductors are used to locate the pointer in the usual manner. Because the carrier signal contains no frequency component of the modulating signal, the driving grid and receiving grid are sufficiently decoupled.