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7079598 Complex phase-locked loop demodulator for low-IF and zero-IF radio receivers  
A digital demodulator which coherently demodulates a low-IF or zero-IF complex signal using a complex-valued phase-locked loop (CPPL). The CPPL includes a numerical controlled oscillator, four...
7006806 System and method for SAP FM demodulation  
Certain embodiments of the present invention provides a system and method for SAP FM demodulation. The system includes a bandpass filter for isolating the SAP signal, a Hilbert filter to produce a...
6950640 FM detector circuit  
An FM detector circuit includes a bridge circuit having four sections with a discriminator connected as one of the four sections. An FM intermediate frequency is applied across one pair of...
6914946 Digitally-implemented demodulator  
A digitally implemented demodulator. A frequency-modulated signal is applied to a limiting amplifier such that the signal amplitude is fixed at a constant level. The signal is undersampled and...
6766148 Switched sideband frequency low-IF transmitter  
A transmitter for transmitting a high frequency transmit signal generates a low intermediate frequency quadrature signal, and up-converts the low intermediate frequency quadrature signal to the...
6621879 Digital radio system, a digital radio device, and a quadrature demodulator  
A digital radio device having a quadrature demodulator that does not suffer from substantial amplitude roll-off at the relevant operating range. Such a device is obtained by a phase shifting...
6586922 Phase shift circuit and FM detector circuit  
Transistors ( 12 a, 12 b ) turn on and off with mutually opposite phase input signals. Capacitors ( 16 a, 16 b ) discharge when the transistors ( 12 a, 12 b ) turn on, and capacitors ( 16 a, 16...
6573782 Sigma delta FM ratio detector  
A circuit ( 100 ) for generating a ratio signal indicating a ratio of frequency error to signal magnitude of an input signal includes an FM ratio detector ( 110 ) and a sigma-delta...
6545634 Method for detecting and correcting non-linearities in radio-frequency, voltage controlled oscillators  
A method for detecting and correcting non-linearities in radio-frequency, voltage controlled oscillators provides for digitization of the frequency signal by feeding the undelayed frequency signal...
6396338 Variable delay line detector  
A variable delay line detector ( 34, 48, 66 )includes a power splitter ( 36, 50, 68 ), a mixer ( 44, 62, 72 ) and a variable delay line ( 42,52, 70 ). Various devices are suitable for the variable...
6335659 Demodulator circuits  
A frequency modulated signal demodulator circuit includes a phase shift element and a time delay element which operate on an input signal (V_IF). The phase shift element and the time delay element...
6229386 Digital FM demodulation circuit  
A digital FM demodulation circuit which samples an input analog FM signal and digitally detects the sampled input signal has an arctangent circuit into which a second signal that is delayed from...
6137353 Linearized integrated FM demodulator using a plurality of cascaded all-pass filters or a bessel filter  
An approach for demodulating a frequency-modulated signal involves processing a frequency-modulated signal with a phase shifter network to provide a demodulated signal that has a relatively...
6084923 System, apparatus and method for averaging digitized phase samples  
The present invention is directed to a system, apparatus and method for averaging digitized phase values. In particular, the polar coordinates represented by the digitized phase values are...
6081155 Digital quadrature discriminator for demodulation of frequency-modulated information  
A circuit is designed with a delay circuit (102) coupled to receive a frequency-modulated data signal (100) at a delay input terminal. The delay circuit produces the data signal (103) after a...
6046630 π/4 QPSK digital demodulating apparatus and a method thereof  
In a digital demodulation apparatus of a QPSK receiver which demodulates an input signal being modulated in the QPSK method by separating into an I (In Phase) channel signal and a Q (Quadrature)...
6020784 FM demodulation circuit  
An FM demodulation circuit includes a phase conversion circuit which converts a frequency variation of an input signal into a phase variation and has a variable conversion characteristic, and a...
5990733 Delay line ramp demodulator  
An integrated circuit includes a demodulator having delay circuitry and demodulation control circuitry that may be fully formed within a common integrated circuit. The delay circuitry receives an...
5942937 Signal detection circuit using a plurality of delay stages with edge detection logic  
A signal detection circuit employs a delay line with edge detection logic for capturing and buffering timing information about an input signal. A plurality of comparators for comparing the input...
5850161 Digital FM demodulator using pulse generators  
A frequency modulation (FM) signal demodulating circuit having a simple structure using general digital devices is provided. The FM signal demodulating circuit according to the present invention...
5826181 Radio frequency noise reduction arrangement  
A frequency selective noise reduction circuit and finds application in receiver demodulator arrangements in mobile telecommunication base stations. A receive signal is divided into two paths. One...
5808510 Demodulator for the demodulation of a frequency-modulated signal  
Radio receivers for frequency-modulated signals and more particularly, in such receivers, to a device for the demodulation of a signal modulated at intermediate frequency f i . The signal F M that...
5751188 FM demodulator using a switched capacitor phase shifter  
In order to process an input signal exhibiting a frequency modulation about an intermediate frequency, the demodulator includes a first mixer for producing a first signal exhibiting the frequency...
5703527 Frequency modulated signal demodulator circuit and communication terminal equipment  
A frequency modulated signal demodulator circuit wherein an in-phase component (I) and an orthogonal component (Q) of a frequency modulated signal output from an orthogonal detector circuit are...
5697086 Co-channel FM signal/interference canceller  
A combination of two phase-lock loops, and a cancellation circuit are used to remove a dominant FM signal from within a signal environment. The two phase-lock loops together produce a replica of...
5694080 Delay-type FM demodulation circuit  
A delay-type FM demodulation circuit of this invention has an object to satisfactorily remove a harmonic wave in an arithmetic calculation output signal even if an LPF having relatively moderate...
5448202 Sigma-delta FM demodulator  
Digital frequency demodulation is accomplished by monitoring similar transitions in an FM radio signal to determine frequency. Time intervals between similar transitions in the FM signal are...
5440269 Digital FM demodulator having an address circuit for a lookup table  
In a digital frequency demodulator, data representing the input signal to be demodulated is prestored in a look-up table and signal processing is digitally performed to generate a read address...
5418489 Method of recovering a frequency modulated signal  
An apparatus and method is provided of recovering a frequency modulated signal having a first component of the frequency modulated signal at a zero-RF spectral location and a second component of...
5416803 Process for digital transmission and direct conversion receiver  
The transmitter uses a synthesized oscillator (1A) whose reference (24) is provided by the clock (H) of the data (P, Q). The demodulation oscillator (13A) of the receiver is a synthesizer which is...
5345188 Sigma-delta digital FM demodulator  
Digital frequency demodulation is accomplished by monitoring similar transitions in an FM radio signal to determine frequency. Time intervals between similar transitions in the FM signal are...
5341107 FM quadrature demodulator with two phase comparison circuits  
FM quadrature demodulator having in-phase and quadrature terminals for applying a pair of FM-modulated signals in a mutual phase quadrature thereto, having a modulation signal which is...
5302910 FM detector circuit with error voltage applied to phase shifting circuit  
In an FM detector circuit, a phase-shifting circuit is constituted by integrating circuits each consisting of a transconductance amplifier and capacitor. The phase-shifting circuit being arranged...
5241687 Phase controlling phase of local subcarrier signal to correspond to transmitted pilot signal  
Apparatus for demodulating information signals frequency-modulated on an RF carrier signal carrying spectral components within the audio frequency range, a pilot carrier signal having an imparted...
5204635 Digital FM demodulator utilizing uncorrelated clock reference signals  
An FM demodulator which generates a modulated object signal directly in digital form, wherein an input FM signal is phase detected, then converted to digital form, then quantized into a pulse...
5179731 Frequency conversion circuit  
A circuit array for frequency translation by means of quadrature heterodyne signals has very low quadrature errors even at very high frequencies and is monolithically integratable with little...
5157344 Digital quadrature phase detector for angle modulated signals  
An analog angle modulated signal is converted into a digital signal within an A/D converter using a sampling clock having a frequency an integer times higher than the carrier of the angle modulated...
5119199 FM demodulator for video tape recorder  
An imput for receiving FM modulated video signals is connected to a first demodulator circuit, the output of which is connected to the first input of an adder. The input is also connected to a...
5095536 Direct conversion receiver with tri-phase architecture  
A direct conversion receiver having a tri-phase architecture including three separate baseband signal channels. RF communications signals which are being tuned by the receiver are split into three...
5077538 FM demodulator with carrier shift compensation  
A circuit arrangement which includes an FM demodulator having a delay circuit which subjects the received FM signal to a preset time delay and a signal combining circuit which combines the delayed...
5053717 FSK demodulator  
An improved multilevel FSK demodulator, according to the invention, is provided that down-converts the IF frequency back to baseband quadrature via dual mixers. The improved multilevel FSK...
4994754 Digital FM demodulating apparatus  
A digital FM demodulating apparatus includes a phase detector for detecting the phase of an input digital FM signal; a differentiator for time differentiating the signal from the phase detector to...
4992747 Multiple reuse of an FM band  
A signal receiving system for receiving messages from each of several unequal amplitude FM carriers occupying the same portion of the frequency band. The signal receiving system receives power...
4988960 FM demodulation device and FM modulation device employing a CMOS signal delay device  
A signal delay device comprises a CMOS gate circuit having an input terminal to which a binary input signal to be delayed is applied, an output terminal from which a delayed signal is derived and...
4985684 Fully integrated digital FM discriminator  
A single substantially non-programmable fully integrated circuit for a digital frequency modulated discriminator is provided whereby frequency variations of a digitized frequency modulated...
4970469 Phase detector and frequency demodulator including such a phase detector  
Phase detector having a first input for an angle-modulated input carrier to be detected, and a second input for a reference carrier having a phase shift which is dependent on the angle modulation...
4951001 Limiter and detector circuit and method  
The invention utilizes a commercially available so-called "quad-pack" of logic gates; i.e. four exclusive OR or exclusive NOR gates mounted in a package. With minimal use of additional components...
4926133 FM demodulator having a frequency independent delay circuit  
An FM signal demodulator for converting the frequency of an input signal to a corresponding voltage. The demodulator includes a delay circuit responsive to the input signal for delaying the phase...
4926132 FM detector with reduced distortion  
An FM detection circuit utilizes a first multiplier and phase shift circuit to demodulate an FM signal. The output signal also contains harmonic distortion as a result of the demodulation process....
4922206 Method of demodulation using split delay line  
A method is disclosed for demodulating binary differential phase shift keyed signals in the presence of carrier frequency uncertainties. In phase modulation, a data signal is impressed on a carrier...
Matches 1 - 50 out of 122 1 2 3 >