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8174310 |
Quadrature modulation demodulation circuit
A quadrature demodulation circuit includes: first to fourth mixers to receive a modulation signal; a phase shifter to supply to the first and third mixers a first local frequency signal, to supply...
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8077818 |
Radio receiver
A radio receiver including a reception processing system that uses discrete-time frequency conversion to acquire a signal having a sampling rate corresponding to a local frequency, wherein the...
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7893758 |
Quadrature modulator and calibration method
A quadrature modulator and a method of calibrating same by applying a first test tone signal to an in-phase modulation branch input of the modulator and a ninety degree phase-shifted version of the...
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7683601 |
Digital acquisition device for an amplitude modulation signal
The invention relates to a digital acquisition device for an amplitude modulation signal of a carrier. The acquisition device digitally acquires a useful signal. The useful signal modulates the...
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7639821 |
System and method for improved detection of AM signals
A software defined radio detects an amplitude modulated (AM) signal contained within a received signal. This detection involves first receiving a radio frequency (RF) signal that contains the AM...
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7567131 |
Device for ultra wide band frequency generating
Devices (1) for exchanging ultra wide band signals comprise frequency translating stages (20,30) for frequency translating signals and oscillating stages (40) for supplying main inphase/quadrature...
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7567641 |
Sample rate conversion systems with an independent internal oscillator
Because of the natural ability to reject clock jitter, the SRC circuits include an internal oscillator to provide an operating clock signal. The internal oscillator can be operated independently of...
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6927623 |
Amplitude-modulated signal receiving circuit
To improve the quality of the demodulated signal without altering the form in which an AM radio wave is transmitted, the received amplitude-modulated signal is converted to a single-sideband...
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6847256 |
Electromagnetic transponder reader
A method and a circuit for demodulating a signal transmitted by an electromagnetic transponder, including a sensor of a variable which is a function of the load formed by the transponder on an...
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6744309 |
Absolute value amplitude baseband detector
Amplitude detection of a baseband electrical signal. The detection may be performed by performing full wave rectification on both an in-phase portion of the electrical signal, as on a...
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6735428 |
Wireless communication apparatus
A wireless communication apparatus prevents desensitization in a line signal frequency caused by clock signal harmonic. The wireless communication apparatus is provided with a receiver/demodulator...
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6512799 |
Digital communication system and method for increased bit rates
A digital communication system and method is provided for increasing bit-rates while maintaining the reliability of transmitted digital information and avoiding increased power demands. The...
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6366164 |
Integrated circuit layout for LF - signal acquisition in the case of contactless data transmission
Integrated circuit layout for LF signal acquisition in the case of contactless data transmission Known circuit layouts for LF signal acquisition only provide for a very short communication distance...
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6181198 |
Amplitude and phase demodulation circuit for signals with very low modulation index
An amplitude and phase demodulator circuit for signals with very low modulation index, including: amplifier circuitry adapted to amplify a modulated signal coming from a transmitter, the modulated...
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5946358 |
Receiver circuit for a mobile communications system
A PHS relay station demodulates a digital signal from a received radio-frequency signal by use of a reproduction clock produced from the digital signal. The relay station has an oscillator which...
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5912929 |
Method and apparatus for performing carrier detection
A digital implementation for a carrier detector. The detector determines if the carrier frequency at any instant is within a predetermined frequency band. The detector further determines if the...
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5579338 |
Spread spectrum receiver using partial correlations
A complex baseband signal as long as one period of PN signal is divided into three sequences. The three partial signals are input to three correlators which then calculate the correlations between...
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5548244 |
Method and apparatus for eliminating DC offset for digital I/Q demodulators
A method and apparatus utilizing the techniques of frequency shifting and filtering for converting an input signal having a desired signal at intermediate frequency and an undesired DC offset to a...
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5469126 |
I/Q-modulator and I/Q-demodulator
An I/Q-modulator or I/Q demodulator circuit in which the modulating signals (2, 3) are input through the output phase transfer branches of the circuit. In relation to the RF-characteristics, a...
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5452331 |
Symbol lock detection implemented with nonoverlapping integration intervals
A symbol lock detector for an incoming coherent digital communication signal which utilizes a subcarrier modulated with binary symbol data, dk, and known symbol interval T by integrating binary...
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5379456 |
Multiplying saw phase shift envelope detector
A radio-frequency detection apparatus including a signal input for providing an input signal and a phase shifter having a first connection and a second connection. The phase shifter includes a SAW...
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5339040 |
AM demodulation receiver using digital signal processor
An amplitude modulated (AM) radio receiver uses a digital signal processor, responsive to in-phase (I) and quadrature-phase (Q) component signals, to compensate for carrier energy removed by a...
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5121057 |
Media flaw detection apparatus for a magnetic disk drive with squaring and summing of in-phase and quadrature-phase detected signals
A media flaw detection apparatus having a sensitivity which is independent of the location of the flaw relative to the written test signal. The apparatus is equally sensitive to missing or extra...
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5095363 |
Method of demodulating multi-standard TV signals and a circuit device for implementing the method
A method of demodulating multi-standard TV signals consists of providing a plurality of signals at a frequency which is a multiple of a reference frequency whose value is a common submultiple of...
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5052401 |
Product detector for a steady visual evoked potential stimulator and product detector
An automated visual testing system is disclosed which presents an alternating steady state visual stimulus to a patient through an optical system that modifies the stimulus image. As the image...
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5029271 |
Superregenerative detector
An improved superregenerative detector including input elements for receiving a high frequency carrier signal having an amplitude envelope upon which an information signal is impressed, the...
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5006811 |
Dual quadrature frequency converter
A method and apparatus for modulating or demodulating a radio frequency (RF) signal which incorporates a pair of quadrature couplers. In demodulating an RF signal, an LO signal and the RF signal...
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4955039 |
Quadrature receiver
A quadrature receiver is disclosed which contains two mixers (M1, M3) in an in-phase receiving path and two mixers (M2, M4) in a quadrature receiving path for converting a received signal to a low...
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4945313 |
Synchronous demodulator having automatically tuned band-pass filter
In a synchronous demodulator for demodulating a carrier signal modulated with a useful signal, the demodulator including a filter circuit (2) for selecting the carrier signal, a limiter (3) for...
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4943982 |
Baseband carrier phase corrector
A baseband carrier phase corrector is disclosed which permits rapid demodulation and demodulation of varying RF input signals. The baseband carrier phase corrector receives RF signals, or...
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4929905 |
Synchronous demodulation circuit for a carrier-modulated television signal
In a synchronous demodulation circuit for an IF television signal, having a passive carrier regenerator (37, 39), a quadrature component unwantedly demodulated by a synchronous in-phase demodulator...
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4907092 |
Modulating/demodulating circuit for multiplex recording/playback of data in a magnetic recording/playback system
A data signal is modulated by an exclusive-OR operation applied to a carrier signal and a data signal to be recorded. Demodulation is similarly performed by an exclusive-OR operation applied to the...
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4862098 |
Continuous-wave-modulation detectors using prediction methods
A detector for a first continuous-wave-modulation signal is supplied an unmodulated carrier signal in addition to the first continuous-wave-modulation signal. Means are provided for modulating the...
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4833417 |
Synchronous demodulation system with digital output
A synchronous demodulation system with digital signal output contains a summation circuit receiving an input signal to be demodulated and a control signal. The output of the summation circuit is...
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4726069 |
A muiti-mode modulation and demodulation system and method
An improved system and method for modulation, demodulation and signal processing for single sideband communications systems which provides correction for the adverse effects of rapid fading...
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4677690 |
Baseband demodulator for FM and/or AM signals
A demodulator of the type employed in a "zero-IF" system uses a local oscillator for providing quadrature output signals at the center frequency of a received signal to be demodulated. The...
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4636736 |
Variable phase signal demodulator
A dual conversion variable bandwidth telemetry receiver employs a phase locked loop which controls the second local oscillator to maintain lock on the carrier frequency; the phase locked loop...
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4631485 |
Synchronous demodulator for amplitude modulated signals
Two circuits carry out the beating of a modulated signal, with first and second signals, respectively, each having substantially the same frequency as the carrier of the modulated signal but...
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4611177 |
Signal demodulator using a multiplying digital-to-analog converter
By using a multiplying digital-to-analog converter for signal demodulation in the disclosed detection scheme, the demodulating signal from the local oscillator can be in digital form without...
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4560942 |
Demodulation circuit having triangular wave for blocking harmonics
A demodulator circuit for demodulating a signal which varies substantially sinusoidally with time, such as a stereo signal having a carrier frequency, comprises a mixer circuit having a first input...
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4471311 |
Detector circuit having AGC function
An AM detector circuit capable of performing an AGC function having a wide dynamic range and low level of distortion and spurious interference. A first differential amplifier receives an...
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4387398 |
Television video signal detector
The video IF signal is applied to a carrier amplifier so that the signal is amplified and limited in amplitude and consequently only the carrier can be derived. The video IF signal is also...
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4371747 |
AM Stereophonic decoder
A decoder for use with a compatible AM stereophonic signal utilizes a amplifier and a feedback loop from the amplifier output to control the output of a multiplier circuit which is one input to the...
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4370676 |
Carrier regenerating circuit for a synchronous detector
A synchronous detector for detecting an information signal modulated onto a carrier, such as a video IF signal, is disclosed in which there are provided a circuit for supplying the modulated...
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4307347 |
Envelope detector using balanced mixer
An envelope detector with an extended linear dynamic range. A first amplitude modulated carrier signal, which can be of an intermediate frequency, is supplied to a first input terminal of a mixer,...
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4228546 |
AM Radio receiver
In an AM receiver, an intermediate frequency amplifier stage is excluded, but a harmonic oscillation circuit is provided for producing a signal synchronous with an amplitude-modulated signal...
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4167650 |
Stereo signal demodulating circuits
A stereo signal demodulating circuit of a switching type is provided with a differential amplifier to obtain difference signals between two output signals from the switching circuit. The difference...
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4163196 |
Demodulating apparatus with phase shift compensation
Demodulating apparatus for a modulated signal comprised of a carrier deriving circuit which is supplied with the modulated signal and which derives an unmodulated carrier therefrom, the carrier...
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4130806 |
Filter and demodulation arrangement
A digital filter and demodulation arrangement for passband signals, whose corresponding baseband signal has a bandwidth limited to a given maximum frequency. The passband signals are filtered...
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4105981 |
Synchronous demodulation device
A demodulation signal results from the sum or difference of two output signals, respectively from two demodulators applied in parallel with the signal for demodulation and in quadrature by a local...
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