Matches 1 - 50 out of 122 1 2 3 >
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7561002 Method and apparatus for frequency modulating a periodic signal of varying duty cycle  
A method and apparatus for frequency modulating a PWM involves 1) generating a high frequency carrier signal much greater in frequency than the PWM signal; 2) modulating the high frequency signal...
7474707 Bandwidth reduction of an FM broadcast signal using a baseband precompensation technique  
A method of processing a baseband multiplex signal comprises the steps of frequency modulating the baseband multiplex signal to produce a first modulated signal, filtering the first modulated...
7417509 Spread spectrum modulation of a clock signal for reduction of electromagnetic interference  
A spread spectrum frequency modulated oscillator circuit usable as a clock comprises a reference component such as a resistor, a voltage controlled oscillator and a first circuit coupled to the...
7376399 Weighted mixing circuitry for quadrature processing in communication systems  
Mixing circuitry for quadrature processing in communication systems and related methods are disclosed. The weighted mixing circuitry allows for arbitrary dividers to be utilized in generating the...
7343139 Device for converting frequencies, method of calibrating said device and system for transmitting/receiving electromagnetic signals comprising such a device  
The invention relates to a device for converting frequencies comprising a local oscillator of fixed frequency and a first mixer with two inputs and an output, a first input receiving the signal to...
7298220 Method and apparatus for creating a multiple loop VCO  
Disclosed herein is a method and apparatus used to create an idealized voltage controlled oscillator (VCO) which allows very high modulation rates without the expected phase noise (jitter) which...
7257166 Data communication apparatus and method based on orthogonal frequency division multiple access  
A data communication apparatus and method based on OFDMA are provided. In a first user transmitting unit through which a user transmits user information to a base station in units of first symbol...
7250823 Direct digital synthesis (DDS) phase locked loop (PLL) frequency synthesizer and associated methods  
The phase locked loop (PLL) frequency synthesizer includes a phase detector receiving a reference signal, a controlled oscillator (e.g. a voltage controlled oscillator) connected to the phase...
7236057 Spread spectrum clock generator  
A clock signal generator varies a frequency of a digital clock over a selected range of frequencies. The generator employs a divider for lowering a frequency of a clock signal. A counter increments...
7158580 Data pulse spectrum control  
The present invention reduces adjacent channel interference for a wireless peripheral device. A direct digital synthesizer generates a waveform having intermediate angular changes during a...
7157985 PLL modulation circuit and polar modulation apparatus  
First and second calibration signals ( 308, 309 ) are sent to a frequency divider ( 102 ) and an adder ( 116 ) of a PLL section ( 100 A), demodulated in a demodulator ( 111 ), filtered through a...
7127020 Frequency synthesis loop having controlled loop gain  
A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase...
7095798 System and method for post filtering peak power reduction in multi-carrier communications systems  
A system and method for post filtering signal peak reduction adapted for use in a multi-carrier communication system incorporating a source of a multi-carrier communication signal band limited in...
6985539 Peak suppression method and data transmission apparatus  
A peak suppression method detects a peak value exceeding a threshold value of a transmitting signal, forms a peak value prediction signal which is limited to a noise cancelling frequency band of a...
6970052 Modulator immune from temperature variation-induced change in modulation factor  
A modulation factor is kept immune from the influence of temperature variation. A modulator is provided with an operational amplifier to one of whose input ends are inputted video signals and to...
6680658 Modulation circuit for wireless installation  
A modulation circuit includes a band restriction filter 2 , an attenuator 3 , a modulator 4 , a reference voltage generator 8 , a comparing reference voltage generator 9 , a voltage comparator...
6677816 Circuit arrangement for demodulating signals  
In a circuit arrangement for demodulating signals, particularly frequency-modulated signals, in which a limiter, to whose input the signals to be modulated can be applied, is followed by a...
6587011 Low cost digital FM modulator  
A modulator including a noise shaper receiving the input signal and providing a signal coded over one bit, a phase loop including an adder and a shift register. The adder receives the signal coded...
6549078 Method and system for directly modulating a voltage controlled oscillator for use in frequency/phase modulated systems  
A method for generating a plurality of frequencies having predetermined frequency deviations from a phase lock loop device including a VCO having a main voltage input, a modulation voltage input...
6545557 FM signal oscillator circuit and modulation level control method  
An FM signal oscillator circuit includes a resonator having a graded- or abrupt-junction variable capacitance diode that is producible through standard IC manufacturing processes but causes an...
6518849 Dynamic delay compensation versus average switching frequency in a modulator loop and methods thereof  
The present invention monitors the average switching frequency at the output of the comparator and adjusts the delay compensation accordingly. That is, the switching frequency monitoring circuit...
6504878 Digitally modulated RF amplifier system having improved adjacent sideband distortion reduction  
A digitally modulated RF amplifier system is presented having improved adjacent sideband distortion reduction. This system includes the provision of a first RF carrier signal at a first frequency...
6476684 Low noise frequency modulator having variable carrier frequency  
A frequency modulator having variable carrier frequency is provided. A VCO frequency-modulates an oscillator input signal using an oscillation frequency set by a set signal as the carrier...
6449470 Method and device for estimating the frequency offset in a signal received by a mobile-telephone demodulator  
Device for estimating the frequency offset in a signal received by a differential demodulator of a mobile-telephone set, intended for implementing the method according to one of claims 1 to 3 ,...
6414560 Loop delay compensation for a digital power amplifier  
A modulator loop is described having an associated band pass frequency range and including a switching stage having a first delay associated therewith. The modulator loop also includes a modulator...
6400415 System and method for predistorting signals to be amplified  
A system and method for predistorting a signal which is to be amplified by a non-linear amplifier. The system and method uses additional predistortion circuits to eliminate the predistortion caused...
6373901 Method and apparatus for conditioning modulated signals using window expansion  
A modulated signal, having a varying magnitude signal envelope, is conditioned, such as to facilitate amplification ( 500 ). Minimum values are determined values for portions of the signal envelope...
6320912 Digital modulator  
There is disclosed a digital modulator whose modulation parameter can be controlled and in which modulation data or modulated signals are prevented from generating interference signals with...
6298096 Method and apparatus for determination of predistortion parameters for a quadrature modulator  
A transmit modulator which uses a quadrature modulator has a predistortion block which produces a predistorted output signal. The predistortion block pre-compensates for errors introduced by the...
6252472 Modulator having little parasitic coupling  
The present invention relates to a modulator comprising an oscillator which has an oscillation frequency, and a mixer intended to supply a modulated signal with a given output frequency. According...
6222890 Variable spectral shaping method for PCM modems  
A method of shaping a transmit spectrum of a PCM modem comprising: selecting a first symbol from a first subset of predetermined symbols; converting said first symbol to its linear value equivalent...
6114921 Double-balanced modulator and quadri-phase shift keying device  
A double-balanced modulator in which the bias voltages do not become different by a buffer amplifier or the like connected to the front stage and a carrier wave is not leaked is provided. This...
6046650 Oscillator circuit having optimized frequency modulation circuit  
A voltage controlled oscillator circuit (58) having a modulation input port (60) for receiving a modulation input signal through modulation circuit (62, 64, 66, 68) and a frequency resonator...
6034573 Method and apparatus for calibrating modulation sensitivity  
A method and apparatus for continuously calibrating the modulation sensitivity of a voltage controlled oscillator (VCO) within a modulator of a transmitter. In accordance with the present...
6029060 Mixer with current mirror load  
A multi-stage mixer circuit has two or more mixer stages, each stage having a mixer core and successive mixer cores being separated by one or more current mirrors. By using current mirrors to...
5912926 Method of and apparatus for controlling modulation of digital signals in frequency modulated transmissions  
A programmable apparatus is disclosed for generating a frequency modulated signal at a selected center frequency in accordance with digital data of at least first and second data levels. The...
5909153 Method and apparatus for compensating for delays in modulator loops  
A modulator loop designed to operate in a frequency range of interest is described. The loop includes a loop output terminal and a switching stage, the output of which is coupled to the loop output...
5883551 Quadrature modulator malfunction estimator and modulator stage using it  
A quadrature modulator including two mixers to which two carrier signals are applied and to each of which a modulating signal is applied, output signals of the mixers being applied to a combiner to...
5857001 Off chip driver with precompensation for cable attenuation  
A digital data waveform precompensated for off-chip cable attenuation includes peaks with exponential tails at signal transitions. A driver output stage generating the waveform includes an output...
5847619 Method and system for calibrating a quadrature phase modulator  
A calibration system for calibrating a quadrature phase modulator comprises a signal generator for generating a pair of sine-wave signals which are quadrature in phase, an adjusting section for...
5796782 Digital modulator with Root-Nyquist filter  
A digital modulator having a pulse shaping filter which generates and accumulates impulse responses including prior impulse responses and posterior impulse responses to perform a Root-Nyquist...
5731745 High frequency oscillator circuits operable as frequency modulators and demodulators  
The high frequency circuit includes an oscillator connected in a Colpitts configuration. Negative feedback to the oscillator is applied through an amplifier, both to stabilize the circuit and to...
5694433 Efficient linear power amplification  
A method and apparatus for producing amplified signals for communications having reduced adjacent channel energy involving generating a first signal having an undesired amount of adjacent channel...
5663691 Estimator for estimating an operating defect in a quadrature modulator, and a modulation stage using the estimator  
An estimator for estimating an operating defect in a quadrature modulator, including two mixers to which respective carrier signals are applied, and to which respective modulating signals are also...
5617063 Matched filters for processing related signal components  
A circuit for processing related signal components, such as in-phase and quadrature signal components generated within a modulator, in which a first filter and a second filter are matched such that...
5608761 Method, device, and radio for compensating for modulator frequency drift while allowing for data transmission  
A method (100), a device (300), and a radio (500) are described for compensating for modulator frequency drift while allowing for data transmission in a half-duplex frequency modulated...
5584066 Correcting circuit for mixing circuit receiver using same and frequency spectrum inverting circuit using same  
A double superheterodyne receiver comprising a pair of first mixer circuits, a pair of second mixer circuits, a demodulator circuit, and a pair of detector circuits. The first mixer circuits are...
5577074 Combined clock recovery/frequency stabilization loop  
The effects of long-term drift in a local reference oscillator are compensated by dividing the local reference oscillator frequency by one of three divider patterns (nominal ratio, add a cycle,...
5568096 Apparatus and method for using negative FM feedback in high quality oscillator devices  
An apparatus and method are provided for increasing the effective Q-value of an oscillator so that the required Q-value can be reached with the use of a low Q-value oscillator. In this apparatus...
5450043 Quadrature modulator with distortion compensation  
A quadrature modulator multiplies two carriers which are 90° out of phase with each other by a sine component and a cosine component of a baseband signal, respectively, adds the product signals to...
Matches 1 - 50 out of 122 1 2 3 >