Showing papers on "Frequency multiplier published in 1982"

Digital radio system

Abstract: Frequency diversity is employed to counter selective fadings as a result of multi-path propagation for troposcatter and short-wave connections for digital useful signals employing frequency modulation. For this purpose, the digital useful signal is supported on a frequency arrangement comprising at least three radio frequencies in that the digital useful signal, together with at least one additional oscillation, and, in fact, an additional fundamental oscillation which determines the frequency of the spacing in radio-frequency frequency arrangement, is fed to the input of a frequency modulator. At the input end, the radio-frequency carriers of the frequency arrangement, which are each modulated with the useful signal, are all converted by coherent mixing into the same frequency level, from which, by way of a combiner, a sum signal is obtained which is the optimum in respect of signal-to-noise ratio.

Microwave subharmonic mixer device

Abstract: A wide band microwave subharmonic mixer includes a signal divider, first and second balanced varistor frequency converters, and a signal combining and dividing circuit. A local oscillator signal is applied to the signal divider, which divides the local oscillator signal into first and second signals. The first signal is applied to the first frequency converter via a coplanar transmission line, while the second signal is applied to the second frequency converter via another coplanar transmission line. The first and second frequency converters each comprise a pair of diodes. Each pair of diodes may be externally polarized by a dc polarization current. The signal combining and dividing circuit receives a microwave signal, and couples the microwave signal to the first and second frequency converters via slotted transmission lines. The first and second frequency converters produce an intermediate frequency signal which is outputted via the frequency combining and dividing circuit. Flanking ground conductors of the coplanar transmission lines may be short-circuited at a predetermined distance from the pairs of diodes.

Single-Gate MESFET Frequency Doublers

Abstract: A simple analytic model of the FET frequency doubler is used to determine the relative contributions of the various nonlinearities to harmonic generation. FET doubler conversion gain and its variation with frequency relative to the fundamental frequency available gain is also estimated. Large-signal computer simulations are used to determine the validity of the analytic model and provide further information on conversion gain and its frequency dependence. The analytic and computer predictions are compared with experimental measurements on a 4- to 8-GHz single-gate FET frequency doubler.

Lock detecting circuit for phase-locked loop frequency synthesizer

Abstract: A phase-locked loop circuit comprising a reference oscillator (1), a reference frequency divider (2) for dividing the output signal of the reference oscillator, a programmable frequency divider (3), a phase comparator (4) for monitoring the difference in phase between the output signal of the two frequency dividers, a lock detector (11) for generating a first signal which is pulse-shaped or rectangular when the above-mentioned difference in phase is generated, and a digital signal maintaining circuit (100) for converting the first signal into a second directed current signal.

Nonlinearity detection using fault-generated second harmonic

Abstract: The tester and method for nondestructively detecting nonlinearity faults in conductors includes the application of a composite AC and DC drive signal to the device under test in such manner that nonlinearities in the device under test produce fault signals including second harmonics, due to local changes of resistance caused by ohmic heating. Electronic filters are used to select out and amplify the second harmonic only, eliminating the direct current and fundamental frequency components of the initial test pulse, plus third and subsequent harmonics. The filtered second harmonic signals from the device under test are then phase-compared to a phase-shifted second harmonic signal produced by a frequency doubler from the test signal generator oscillator to cancel out the second harmonic signals from the good conductor; the remaining phase anomaly signals control a threshold detector remaining to provide fault indication.

Horizontal scanning frequency multiplying circuit

Abstract: A horizontal scanning frequency multiplying circuit comprises a flip-flop supplied with a horizontal synchronizing signal having a horizontal scanning frequency f H , which is set by this horizontal synchronizing signal, a phase-locked-loop, and a counter. The phase-locked-loop comprises a voltage controlled oscillator for producing a signal having a frequency Nf H (N is an integer over 1) which is N times the horizontal scanning frequency f H , a frequency divider for frequency-dividing an output signal frequency of the voltage controlled oscillator, and a phase comparator supplied with one output signal of the flip-flop and an output signal of the frequency divider, for comparing phases of these signals and applying an output error signal to the voltage controlled oscillator to control the oscillation frequency of the voltage controlled oscillator. The counter is supplied with the other output signal of said flip-flop which is reset by this output signal, and supplied with the output signal of the voltage controlled oscillator within the phase-locked-loop as a clock signal, and produces a counted output every time the clock signal is counted for a predetermined counting time T, to supply this counted output to the flip-flop in order to reset the flip-flop. The voltage controlled oscillator within the phase-locked-loop produces a signal having a frequency Nf H .

Synchronizing circuit for a television receiver

Abstract: A synchronizing circuit arrangement for a television receiver having an oscillator which generates a clock signal the frequency of which is substantially higher than the line frequency and having a frequency dividing circuit which derives signals of the line frequency from the clock frequency by means of division. During a predetermined number of line periods a phase comparison stage determines the average value of the phase deviation between the received line synchronizing signal and a reference signal of the line frequency and applies the value obtained to a preset stage for adjusting in a subsequent time interval, for example one line period during the field blanking interval, the divisor by which the frequency dividing circuit divides the clock frequency. The clock frequency may be a multiple of the chrominance subcarrier frequency, in which case the oscillator is continuously readjusted by the phase comparison stage when the color killer circuit is operative, while the divisor is not changed.

FM Transceiver frequency synthesizer

Abstract: A frequency synthesizer used for a frequency modulation (FM) transceiver which uses negative feedback to make the modulation characteristics linear and stable over a wide frequency range. The negative feedback is comprised of a frequency mixer, which mixes the outputs of a local oscillator and a voltage controlled oscillator, and a frequency divider and demodulator, which act on the output of the frequency mixer and supply the demodulated output signal to an adder, where it is added in reverse phase to the modulating signal.

Push-pull microwave oscillator with fundamental and second harmonic outputs

Abstract: A push-pull microwave oscillator circuit, including two transistors, for producing the second harmonic of a fundamental frequency at a symmetry point of the circuit which is connected to the bases of the transistors through identical arrangements of circuit elements. The circuit includes tuning means coupled to at least one of the transistors, an output and an input. The output, which is utilized to provide to a phase comparison means an output signal at the fundamental of the second harmonic frequency, is coupled to the base of at least one of the transistors by a capacitive impedance. The input, which is utilized to receive a tuning signal produced by the phase comparison means in response to the output signal, is coupled to the tuning means.

Signal processing apparatus for frequency domain geophysical electromagnetic surveying system

Abstract: A frequency domain geophysical electromagnetic surveying system is provided in which intermittent primary fields having sharp terminations are generated in a cycle having a fundamental frequency by a transmitter, and a receiver includes a gate passing only secondary signals received during interruptions of the primary field, the gated signal being applied to filters tuned to harmonics of the predetermined frequency. The filter outputs are synchronously demodulated to provide signals corresponding to at least the in-phase component of the secondary signal at the fundamental frequency, and preferably in-phase and quadrature components at at least two harmonics. The system can provide improved resolution particularly of the characteristics of in-phase secondary signals received from terrain being surveyed.

Noise reduction by integrating frequency-splitted signals with different time constants

Abstract: A noise reduction circuit comprising first and second variable frequency amplifiers (3, 4; 12, 13) for respectively amplifying first and second audio signals at variable gains in response to a control signal, a frequency splitter (23-26; 42-45) for splitting each output signal of the first and second variable gain amplifiers into high and low frequency components, an envelope detector (27-30; 46-49) for detecting the envelopes of the high and low frequency components of each audio signal and generating therefrom first and second high frequency component envelopes and first and second low frequency component envelopes, a combining circuit (31, 32; 50, 51) for combining the first and second high frequency component envelopes to generate a combined high frequency output and combining the first and second low frequency component envelopes to generate a combined low frequency output, and means (33-35; 52-54) for integrating the combined high frequency output with a smaller time constant and integrating the combined low frequency output with a greater time constant and combining the integrated outputs to generate a signal as said control signal.

Phase-locked loop circuit with variable bandwidth filter

Abstract: A phase-locked loop circuit comprises an oscillator, a phase comparator which compares the phase of an input signal with the phase of an oscillator signal, a detector which detects when the phase-locked loop circuit is locked within a predetermined frequency range and produces a corresponding lock detecting signal, and a filter circuit including a variable current source which produces a variable current in response to a change of state of the lock detecting signal to control the bandwidth of the filter circuit, a filter element which receives the variable current, a differential amplifier which receives the phase-compared signal, a current mirror circuit which receives the variable current from the variable current source, and a buffer circuit connected to the filter element which supplies an output signal to the oscillator to lock the frequency of the oscillator signal to the frequency of the input signal.

Synchronizing signal generating circuit for solid-state colour video camera

Abstract: A synchronizing signal generating circuit generating a horizontal synchronizing signal applied to a solid-state color video camera comprises an oscillator (1; 1b) generating an oscillation output signal having a frequency which is n (n: an integer) times as high as the horizontal frequency, a frequency divider (12) dividing the frequency of the oscillation output signal from the oscillator to generate a pulse signal having a recurrence frequency equal to the horizontal frequency, and another oscillator (15) generating, in response to the application of the pulse signal to its control terminal, a horizontal clock pulse signal whose oscillation phase is controlled to be maintained at the same fixed phase in each horizontal period.

Fractional-division frequency synthesizer for digital angle-modulation

Abstract: A FRACTIONAL-DIVISION FREQUENCY SYNTHESIZER FOR DIGITAL ANGLE-MODULATION Abstract of the Disclosure In order to deliver an angle-modulated output signal as a function of digital information, the frequency synthesizer delivers an output frequency FS = (N + k)FR, where N is the integral part of a number N+k and FR is a reference frequency. Provision is made for a variable oscillator, an oscillator control loop comprising in series a variable-rank divider prepositioned on the division rank N, a phase comparator for receiving the reference frequency and a summing device. The synthesizer further comprises a phase accumulator for performing at the frequency FRmodulo-M summation of a number G = k.M applied to its input. The sum and carry outputs of the accumulator are coupled respectively to the summing device in order to deliver a signal for compensating the signal delivered by the phase comparator and to the divider for delivering a control signal at N+1 of the division rank. An adder having one out-put coupled to the input of the phase accumulator receives a constant number g on one input and a number dg which is representative of the digital information on another input.

Fast dispersive beam deflectors and modulators

Abstract: A new method for one-dimensional light scanning is proposed. It is based on the use of ordinary dispersive optical components like prisms, gratings, etc. By electrooptic tuning of the output wavelength of broad-band lasers, fast scanners (up to 10 gigapixels/s) can be constructed. Deflection angles and numbers of pixels are derived for the prism, grating, Fabry-Perot etalon, and phase-matched frequency doubler crystal. Experimental results on the frequency doubler device are presented.

System for detecting abnormal condition of high frequency output signal in its power level

Abstract: A system for detecting an abnormal condition of a high frequency output signal in its power level, comprising: a variable gain power amplifier which receives a high frequency input signal and produces an amplified high frequency output signal; a negative feedback control loop connected to the power amplifier, for automatically setting the power level of the amplified high frequency output signal to a desired one of a plurality of predetermined power levels, the negative feedback control loop being so arranged as to produce a DC signal which is constant in its magnitude so far as the power level of the high frequency output signal is maintained at its set value whichever one is selected from the plurality of predetermined power levels, the gain of the power amplifier being controlled on the basis of the DC signal; and a comparator which compares the DC signal with a reference signal to judge as to whether the high frequency output signal is abnormal or not in its power level.

Notch filter system

Abstract: A notch filter system for eliminating a specific "stop" frequency from an AC electrical input signal, such as 60 Hz "hum" from an audio program signal. An L/C tuned circuit that is tuned to the stop frequency is used to develop a modified input signal that is in phase with the input signal only at the stop frequency. The two signals are amplitude-balanced and fed to the respective inputs of a balanced differential amplifier which is responsive to both input signal phase and amplitude differences so as to cancel the signals at the stop frequency where they have the same phase and amplitude but not at frequencies above and below the stop frequency where they differ in phase and amplitude.

Superheterodyne circuit having variable bandwidth and center frequency shift function

Abstract: The invention relates to a superheterodyne circuit characterized by comprising a first mixer converting a received signal into the first intermediate frequency, a second mixer converting the first intermediate frequency into a second intermediate frequency, and a product detection stage demodulating the second intermediate frequency to an audio frequency, by having a constitution wherein the local oscillation of the first mixer is input from a VCO for which a PLL circuit is used, wherein the local oscillation of the second mixer is an output obtained by mixing the frequency of a second oscillator with that of a third oscillator in a fourth mixer, wherein the second oscillator combined with the frequency of the VFO in the sixth mixer, alone or in further combination with the frequency of the output of a BFO input via to the product detection stage is the frequency of the third oscillator or an output obtained by mixing the frequency of the third oscillator with a frequency obtained through the frequency division or multiplication of the frequency of the first oscillator in a fifth mixer, and wherein the output of the second oscillator is input to the fourth mixer and, at the same time, a frequency obtained by mixing said output with the output from a VFO in a sixth mixer is directly input to a third mixer of the PLL circuit, or an output obtained by mixing said frequency with the frequency of the first oscillator or with a frequency obtained through the multiplication or frequency division of the frequency of the first oscillator in a seventh mixer is input to said third mixer, and by conducting a variation of the total bandwidth of an intermediate-frequency stage and a shift of the center frequency by setting a reception band determined by the relationship between the set frequency-division ratio of a programmable frequency divider in the PLL circuit and the frequency of the first oscillator input a seventh mixer or a frequency obtained through the multiplication or frequency division of said frequency, by tuning a received frequency determined by the frequency of the VFO, and by varying the frequency of the second or third oscillator or by simultaneously varying the frequencies of the second and third oscillators.

Video signal processing device including emphasis and/or de-emphasis circuit

Abstract: A video signal processing device including emphasis and/or de-emphasis circuit being arranged to have a circuit to emphasize a high frequency component of a video signal which has been introduced at a time of frequency modulation in a linear phase. Further, the circuit clips an output of the emphasis circuit with a prescribed amplitude and at the same time supplies a frequency modulated video signal to a de-emphasis circuit which has a characteristic of being contrary to the frequency characteristic of the emphasis circuit.

A packaged Schottky diode as detector, harmonic mixer, and harmonic generator in the 25–500 GHz range

Abstract: This paper describes experimental results obtained with a packaged GaAs Schottky barrier diode in contact with a coaxial connector and placed across waveguides for bands Ka, V, E, W or F. Among the microwave sources used for calibration were 9 carcinotrons in the frequency interval 51–490 GHz. As soon as the frequency F is above the waveguide cut-off frequency, the different characteristics do not depend critically on the waveguide size for V, E, W and F bands. The video detection sensitivity, of several 100 mV/mW at 50 GHz and below, decreases as F−4 in the range 51–500 GHz. Coupling an X-band centimeter frequency via the coaxial connector and a millimeter frequency via the waveguide permits harmonic mixing in the diode. Between 36 and 490 GHz, the harmonic mixing number varies from 3 up to the very large value 40 with conversion losses from 18 to 88 dB. The minimum detectable signal in the 100 kHz band can be as low as −90 dBm at 80 GHz. A noticeable millimeter power is available at the waveguide output from injected centimeter power by harmonic generation. Starting for instance with 100 mW around 11.5 GHz, we have measured 0.1 mW at 80 GHz and 0.1 μW at 230 GHz. To illustrate the possibility of creating usable millimeter and submillimeter wave without heavy equipment (such as carcinotrons or millimeter klystron) we report spectroscopic experiments in Rydberg atoms. Resonances have been observed up to 340 GHz by harmonic generation (28th harmonic) from an X-band klystron).

A synchronous frequency multiplier using phase-locked loop

Abstract: A useful technique to multiply the frequency of an input square wave by n times without losing synchronization with an original waveform is proposed. A circuit which implements this technique for f = 50 Hz and n = 12 is described and experimental results are given.

A High Performance Frequency Doubler for 80 to 120 GHz

Abstract: A frequency doubler for the 80- to 120-GHz output band is described. The device may be operated in either a fixed-tuned or a tuneable mode. When operated fixed-tuned, with a constant dc bias applied to the diode, the conversion loss for any output frequency between 80 and 120 GHz is 9.2 dB, +-1.2 dB. When used so that toning and bias are optimized at each operating frequency, the doubler exhibits conversion loss less than 7.5 dB for any frequency between 90 and 124 GHz.

Device and method for recording information on a disk

Abstract: A disk recording device of the invention has a detector for detecting the position of an optical head with respect to the radial direction of a disk, using an optical scale, and a position signal processing circuit for generating a position signal from the output signal from the detector. An output signal from the circuit is converted by a D/A converter into a voltage signal, which is supplied to a voltage controlled oscillator. The oscillator generates a frequency signal. The frequency signal is supplied to a page buffer storing video data and one input of an AND circuit. The other input of the AND circuit is connected to receive a video data from the page buffer. The AND circuit generates a logic product of the frequency signal and the video data, or a recording timing signal having a frequency which is proportional to the position of the head with respect to the radial direction of the disk.

Plural phase locked loop frequency synthesizer

Abstract: First and second frequency signals are frequency converted by a frequency converter and the frequency-converted output and the output from a variable frequency oscillating means are phase compared by a digital phase comparator. The phase-compared output controls the variable frequency oscillating means, constituting a first phase lock loop of a wide capture range. The output from the variable frequency oscillating means is frequency converted by the first frequency signal and the converted output and the second frequency signal are phase compared by an analog phase comparator. By the phase-compared output is controlled the variable frequency oscillating means, constituting a second phase lock loop of a narrow capture range but a large loop gain. The output frequency of the variable frequency oscillating means is varied by changing the setting of the frequencies of the first and second frequency signals.

Wide band frequency phase locked loop frequency synthesizer

Abstract: The synthesizer comprises a single phase loop formed by two stages of a frequency divider inserted between the voltage controlled oscillator and the phase comparator. The synthesized frequency is taken from the connection between the two stages, which allows a frequency range to be obtained extending over a wide band with a voltage controlled oscillator itself having a small relative band width.

Tuning apparatus of phase-locked loop type

Abstract: A tuning apparatus of phase-locked loop type having a voltage controlled oscillator which is working as a local oscillator of a tuning circuit, a programmable divider supplied with the output signal from the voltage controlled oscillator, a reference frequency signal generating circuit, a phase comparator supplied with the output signal from the voltage controlled oscillator and the output signal from the reference frequency signal generating circuit, and supplying the output signal to the voltage controlled oscillator, the programmable divider, the reference frequency signal generating circuit and the phase comparator being formed in a single integrated circuit, and a control circuit formed separately from the integrated circuit for supplying a control data to the programmable divider in the single integrated circuit is disclosed, in which the integrated circuit further comprises a memory for memorizing the control data which is serially supplied from the control circuit and supplying the control data to the programmable divider in parallel.

Voltage controlled oscillator using a voltage tunable filter with feedback

Abstract: A voltage controlled oscillator for producing an output signal having a frequency proportional to the magnitude of an input control signal includes a tunable filter circuit for simulating a resistance-inductance-capacitance (RLC) circuit with a resonant frequency approximately equal to the base or center frequency around which the voltage controlled oscillator is to operate. Through appropriate feedback means and multiple gain paths within the simulated RLC circuit, there is provided an output signal whose frequency is a function of the input control signal.

Frequency modulation transmitter

Abstract: A frequency modulation transmitter has a frequency synthesizer (8) comprised of a voltage controlled oscillator (1) for operating a transmitter section (33) of the modulation transmitter. The output center frequency of the voltage controlled oscillator (1) is determined by channel designation information. The level of a modulation input signal (11) applied to the voltage controlled oscillator (1) for modulating the center frequency is changed in accordance with the channel designation information.

Phase-lock device for supplying at its output signals whose frequency may vary over a wide band

Abstract: This phase-lock device is provided in order to furnish at its output terminal (20) signals whose frequency may vary over a wide band; this device comprises a VCO (10), a phase detector (30), a low- pass filter (45) provided to determine the operating characteristics of the said device and a frequency divider (25). This device further comprises a gain-varying circuit (60) for varying the value of the output signal from the phase detector and a circuit (62) which measures the value of the signal applied to the frequency control of the VCO in order to vary the gain of the varying circuit so as to keep the said characteristics practically constant within the band. Application: to frequency synthesizers.

Sample hold circuit for an image pick-up device

Abstract: A dot sequential color signal which is generated in an image pick-up means, as for example a CCD type image sensor is supplied to a first sampling and hold (S/H) circuit, with the frequency of the sampling pulse used in the first S/H circuit being at a predetermined frequency (FO), and the output of the first S/H circuit is supplied to a second S/H circuit, with the frequency of the sampling pulse used in the second S/H circuit being selected to be N times of the predetermined frequency (NFo), so that the frequency of the sampling noise caused by the sampling operation is relatively high compared with the output signal of the image pick-up means, and thus the cut-off frequency of a low pass filter for eliminating the sampling noise can be selected to be high enough not to attenuate the desired signal.