Frequency Shift Keying Patents (Class 375/272)
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Patent number: 6950670Abstract: A wireless network includes transmission power and data rate adaptation based upon signal quality experienced by the user.Type: GrantFiled: October 31, 2001Date of Patent: September 27, 2005Assignee: AT&T Corp.Inventors: Li Fung Chang, Kapil K. Chawla, Justin Che-I Chuang, Xiaoxin Qiu
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Patent number: 6937666Abstract: A microwave radio assembly is described including a directional antenna wherein the installation and aiming is simplified. The assembly is attached to the wall-mount fix via gimbals mechanism with one rotation axis for azimuth and one for elevation and the assembly preferably includes a sight mechanism including a pair of visual apertures is located in the radio assembly in a line parallel to the radio antenna radiation direction. The radio assembly further includes a modulation cancellation scheme in full duplex mode.Type: GrantFiled: April 24, 2003Date of Patent: August 30, 2005Assignee: Bridgewave Communications, Inc.Inventors: Eliezer Pasternak, Gregg Levin, Idan Bar-Sade, John Park
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Patent number: 6931089Abstract: A phase-locked loop includes a phase detector which receives an input signal and a first internal periodic signal and provides a phase signal indicative of a phase difference between the input signal and the internal signal. A rotator then receives the phase signal and provides first and second periodic signals each having a frequency that is a function of the phase difference, the first and second periodic signals being 90 degrees out of phase with each other. An interpolator circuit then linearly combines the first and second periodic signals with third and fourth periodic signals to provide the first internal periodic signal. The interpolator circuit may provide a second internal periodic signal that is 90 degrees out of phase relative to the first internal periodic signal. The phase-locked loop may further include a low-pass filter provided between the phase detector and the rotator.Type: GrantFiled: August 21, 2001Date of Patent: August 16, 2005Assignee: Intersil CorporationInventors: Bin Wu, Dong Zheng
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Patent number: 6901246Abstract: A sinusoidal RF carrier is modulated for the transmission of digital binary data streams through the amplitude suppression of carrier wavelets. These wavelets are defined between zero crossover positions representing zero energy locations. This modulation is accomplished when the carrier is slightly amplitude modulated with a modulation signal that is equal in frequency to the carrier itself and the modulation always begins or ends upon the exact zero voltage crossing point of the RF cycle phase. The modulation is applied as a slight shift of the amplitude of any single cycle, each cycle representing a single bit of data. A single cycle of RF will either represent a “1” or “0” depending upon the amplitude of the cycle, relative to other adjacent cycles in the same carrier.Type: GrantFiled: July 26, 2001Date of Patent: May 31, 2005Assignee: XG Technology, LLCInventors: Joseph Bobier, Nadeem Khan
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Patent number: 6891905Abstract: An FSK receiver comprising: 1) demodulation circuitry for receiving an incoming FSK signal and generating a baseband signal comprising an amplitude modulated symbol stream of Logic 0 symbols and Logic 1 symbols having a data rate, R; 2) auto-correlation circuitry for sampling the baseband signal S times during each symbol and generating an auto-correlation function comprising a sample stream of N-bit samples having a data rate, S×R, and having positive-going peaks approximately coinciding with the center of the Logic 1 symbol in a 010 sequence in the baseband signal and negative-going peaks approximately coinciding with the center of the Logic 0 symbols in a 101 sequence in the baseband signal; and 3) decision circuitry for receiving the auto-correlation function and deciding a logic level of a first symbol as a function of: 1) a comparison of a signal level of a center sample of the first symbol and a mean signal level of the auto-correlation function and 2) a comparison of the signal level of the center samType: GrantFiled: August 23, 2001Date of Patent: May 10, 2005Assignee: National Semiconductor CorporationInventors: Lawrence J. Malone, Aaron D. Lamb
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Patent number: 6865235Abstract: A multi-protocol modulator capable of supporting two or more different modes of operation, each mode of operation corresponding to a different type of modulation, comprises an m-level phase shift keying (m-PSK) modulator which receives a serial input data stream and maps data contained therein into a constellation including m equidistant phases in accordance with a predetermined mapping scheme. The m-PSK modulator is shared by at least two different modulation protocols by allowing the mapping scheme to be selectively changed depending upon the modulation protocol used. The multi-protocol modulator further includes a phase rotator operatively coupled to the output of the m-PSK modulator. The phase rotator selectively rotates the phase of the m-PSK signal by a predetermined phase rotation value. The phase rotator is shared by the two or more modulation protocols by allowing the phase rotation value to be selectively modified depending upon the modulation protocol used.Type: GrantFiled: March 6, 2001Date of Patent: March 8, 2005Assignee: Agere Systems Inc.Inventor: Ramin Khoini-Poorfard
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Patent number: 6862313Abstract: A wireless transceiver comprises a digital to analog converter having an input for receiving a digital representation of a direct sequence spread spectrum signal and having an analog output. A filter has an input coupled to the analog output of the digital to analog converter. An adder has a first input coupled to the filtered output and a second input coupled to a loop control voltage generated by a phase lock loop. A VCO integrated into the phase lock loop has a control input coupled to the summed output. An RF output of the VCO produces a continuous phase frequency shift keyed spread spectrum signal in response to the digital representation of the direct sequence spread spectrums signal. A receiver converts received RF signal to baseband in-phase and quadrature that are in turn converted to digitized signals. A demodulator produces chip data that is despread using a matched filter.Type: GrantFiled: April 18, 2002Date of Patent: March 1, 2005Assignee: Skyworks Solutions Inc.Inventors: John S. Walley, D. Vincent Laub, Norman J. Beamish
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Patent number: 6853687Abstract: An object tracking system for locating radio-tagged objects within a monitored environment has a plurality tag transmission readers that detect RF transmissions from the tags, and generate output signals representative of the time-of-arrival of first-to-arrive tag transmissions. An object location processor processes the first to arrive signals in accordance with a multilateration algorithm to geolocate a tag. In order to modify the operation of a tag that comes within a prescribed region of the monitored environment (such as passing through a doorway), one or more relatively short range, magnetic field proximity-based, tag-programming ‘pingers’, are placed proximate to the region. A magnetic field receiver on the tag detects the field generated by the pinger and causes the tag to change operation such as increase its RF transmission rate.Type: GrantFiled: January 11, 2001Date of Patent: February 8, 2005Assignee: WhereNet CorpInventors: Timothy C. Harrington, Ronald J. Hash, Donald K. Belcher
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Patent number: 6845103Abstract: An apparatus for controlling initialization of a discrete multi-tone (DMT) system is provided in which a connection between first and second devices is acknowledged by using a plurality of connection acknowledgment tone frequencies to thereby improve the reliability of the activation/acknowledgment procedure. The method includes transmitting a first connection acknowledgment tone signal at a predetermined frequency from the first device to the second device; detecting a first response tone signal transmitted from the second device; transmitting a second connection acknowledgment tone signal to the second device if the first response tone signal is not detected for a predetermined time; and detecting a second response tone signal inputted from the second device to thereby acknowledge a connection to the second device.Type: GrantFiled: May 3, 2000Date of Patent: January 18, 2005Assignee: LG Electronics Inc.Inventor: Hyung Jin Park
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Patent number: 6842519Abstract: Apparatuses and methods are disclosed for communications using current detection. According to one embodiment, a transmitter generates a signal on a transmission line by switching between two power sources. According to one embodiment, the transmitted signal is a balanced signal. Under an embodiment, a signal that has been transmitted on the transmission line is received by a receiver that includes a current detector, and the receiver detects the signal by sensing changes in current on the transmission line. According to one embodiment, the current detector includes a sensor that senses changes in the magnetic field generated by changes in current in the transmission line.Type: GrantFiled: April 27, 2001Date of Patent: January 11, 2005Inventors: Stephen Roy Rumbaugh, Garth Wayne Haslam
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Patent number: 6831953Abstract: A method of, and terminal for, detecting the presence of a 2-FSK signal, the method comprising receiving (10) a 2-FSK signal, quadrature frequency down-converting (34,35,36) the received signal to produce quadrature related outputs, oversampling (42,43) the quadrature related outputs to produce digital samples, differentially decoding (44) the digital samples to produce real and imaginary components, integrating (56,58) the imaginary components and comparing (26) the integrated value with a fixed threshold value (24) and determining a signal to be present if the threshold is exceeded.Type: GrantFiled: March 8, 2001Date of Patent: December 14, 2004Assignee: Koninklijke Philips Electronics N.V.Inventor: Domenico G. Porcino
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Patent number: 6816559Abstract: An FSK transceiver circuit, including a controlled oscillator used, in a transmission mode, to modulate a carrier by frequency shifts according to a binary transmission signal present on an input pin of the circuit, the shift amplitude being determined by an adjusting element connected to an adjusting pin of the circuit; two mixers connected to receive a reception signal present on a receive pin and, respectively, two carriers in phase quadrature of the controlled oscillator that, in receive mode, receives no modulating signal; and a demodulator connected to the outputs of the mixers via respective filters, the output of one of the filters being accessible from the outside by a circuit test pin.Type: GrantFiled: March 21, 2000Date of Patent: November 9, 2004Assignee: STMicroelectronics S.A.Inventors: Philippe Sirito-Olivier, Christophe Dugas
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Publication number: 20040218686Abstract: A microwave radio assembly is described including a directional antenna wherein the installation and aiming is simplified. The assembly is attached to the wall-mount fix via gimbals mechanism with one rotation axis for azimuth and one for elevation and the assembly preferably includes a sight mechanism including a pair of visual apertures is located in the radio assembly in a line parallel to the radio antenna radiation direction. The radio assembly further includes a modulation cancellation scheme in full duplex mode.Type: ApplicationFiled: May 11, 2004Publication date: November 4, 2004Applicant: BridgeWave Communications, Inc.Inventors: Eliezer Pastemak, Gregg Levin, Idan Bar-Sade, John Park
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Patent number: 6785347Abstract: Disclosed is a method and apparatus for receiving FSK signals using estimation theory. A received signal is filtered to obtain energy estimates for a first frequency corresponding to a binary “0” and a second frequency corresponding to a binary “1”. The energy estimates are subtracted to obtain a difference value and an odd number of samples of a series of difference values is smooth filtered in order to produce a series of average values. A sliding window is applied to the series of average values that detects a clear majority of sample corresponding to either the binary “0” frequency or the binary “1” frequency in order to produce a binary output signal that corresponds to the received signal.Type: GrantFiled: April 22, 1999Date of Patent: August 31, 2004Assignee: 3com CorporationInventor: Zheng-She Liu
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Patent number: 6774738Abstract: In a method for amplitude trimming in transceivers having a PLL circuit operating on the two-point modulation principle, the amplitude of an analog modulation signal is selected on the basis of a modulation shift of a defined digital modulation signal. A predetermined data sequence of the analog modulation signal is applied, the modulation shift of the analog modulation signal is determined, and the amplitude of the analog modulation signal is corrected to match the difference between the modulation shift of the digital modulation signal and the determined modulation shift of the analog modulation signal.Type: GrantFiled: June 26, 2003Date of Patent: August 10, 2004Assignee: Infineon Technologies AGInventors: Markus Hammes, Stefan Van Waasen
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Publication number: 20040120417Abstract: An encoding system for encoding a first ancillary code in media data and monitoring for reception of a second ancillary code that has a higher priority than the first ancillary code, such that upon detection of the higher priority ancillary code the encoding system modifies a characteristic and/or characteristics of the first ancillary code.Type: ApplicationFiled: December 23, 2002Publication date: June 24, 2004Inventors: Wendell D. Lynch, James M. Jensen
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Publication number: 20040120418Abstract: A microwave radio assembly is described including a directional antenna wherein the installation and aiming is simplified. The assembly is attached to the wall-mount fix via gimbals mechanism with one rotation axis for azimuth and one for elevation and the assembly preferably includes a sight mechanism including a pair of visual apertures is located in the radio assembly in a line parallel to the radio antenna radiation direction. The radio assembly further includes a modulation cancellation scheme in full duplex mode.Type: ApplicationFiled: April 24, 2003Publication date: June 24, 2004Inventors: Eliezer Pasternak, Gregg Levin, Idan Bar-Sade, John Park
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Patent number: 6688714Abstract: The bit rate of a data stream having the following characteristics is modified. The data stream includes control words, each of which defines when a data portion of the data stream has to be read from an input buffer at a receiving end. An MPEG video stream has such characteristics. It is calculated, for at least one future instant in time (Tfut), within which bounds (Rmax, Rmin) the bit rate (R) of the data stream can be modified at that future instant of time, so as to cause neither underflow nor overflow of the input buffer. The bit rate is modified at a future instant in time within the bounds (Rmax, Rmin) which have been calculated for the future instant in time. This allows a fast modification of the bit rate which generally contributes to the quality of the data comprised in the data stream.Type: GrantFiled: March 9, 2000Date of Patent: February 10, 2004Assignee: Koninklijke Philips Electronics N.V.Inventors: Nicolas Bailleul, Etienne Fert, Pierre Gautier
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Patent number: 6650712Abstract: Disclosed is an apparatus and method for low complexity, phase independent reception of FSK signals. A finite series of delay elements produces a plurality of equidistant samples of a received FSK signal. The plurality of equidistant samples is processed by an arithmetic unit using a phase independent algorithm to obtain an estimate of the received signal. The estimate of the received signal is then compared to a threshold value to determine if the estimate corresponds to a binary 1 or binary 0, which increments a counter corresponding to each binary value. Multiple estimates are counted over a baud interval of the received FSK signal and a binary 1 or binary 0 is output as a received data signal value depending upon which binary value the counter having the higher value corresponds to.Type: GrantFiled: July 27, 1999Date of Patent: November 18, 2003Assignee: 3Com CorporationInventors: Alexandre Leonidov, Vitali Vinokour, Benjamin Dolnik
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Publication number: 20030198253Abstract: A data transmission includes a sequence of information symbols followed by zero or more non-information symbols, which carry no power. A receiver determines the size of a data block, i.e., the number of information symbols in the transmission, by calculating a series of transition indicators. Each transition indicator represents a likelihood that a particular symbol position corresponds to a transition between the information symbols and non-information symbols of the transmission.Type: ApplicationFiled: April 22, 2002Publication date: October 23, 2003Inventor: Walid Ahmed
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Patent number: 6618449Abstract: A receiver of a frequency-shift-keying, continuous-wave radar comprises at least sampling means taking real samples of the signals in each reception channel and extrapolation means, the extrapolation means producing fictitious samples synchronous with the real samples, the reception signals being formed out of real samples and fictitious samples. Application especially to radars fitted into automobiles.Type: GrantFiled: February 24, 1999Date of Patent: September 9, 2003Assignee: Thomson-CSFInventors: Philippe Laviec, Pascal Cornic
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Publication number: 20030091121Abstract: To provide a multi-valued FSK communication method and a multi-valued FSK communication apparatus having a simplified circuit configuration for receiving a multi-valued FSK packet. A transmitter side transmits a packet including a synchronization signal part using the maximum value and the minimum value of multi-valued FSK and a payload part using all values of multi-valued FSK. A receiver side receives the packet, and a reception circuit 3 forms an analog demodulation signal Sda by demodulating a reception signal and a binary signal Sb by binarizing the analog demodulation signal Sdm. These signals Sda and Sb are supplied to a received data processing unit 23 of a baseband signal processor 12. The received data processing unit 23 establishes synchronization based on the binary signal Sb.Type: ApplicationFiled: November 13, 2002Publication date: May 15, 2003Applicant: Seiko Epson CorporationInventor: Nobuhiko Kenmochi
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Patent number: 6529565Abstract: Since in a demodulated base band signal in an FSK receiver, etc. usually a DC offset is produced due to a frequency difference between a transmitter and a receiver, etc., which lowers demodulation margin, a circuit is constructed for detecting an error in a center level thereof to correct same in a simple manner. In this circuit, a bit synchronizing signal, which is at a beginning of a the base band signal EB is sampled twice with an interval of 1/(baud rate) sec and an average of two sampled values is obtained by applying sampled output pulses thus obtained to a holding capacitor in a hold circuit. In this way the error in the center level is detected and the center level is corrected by subtracting it from the base band signal in a subtracter.Type: GrantFiled: September 22, 1998Date of Patent: March 4, 2003Assignee: General Research of Electronics, Inc.Inventor: Kazuo Kawai
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Patent number: 6522698Abstract: A method and apparatus for transmitting and receiving data, wherein a narrow band data signal is transmitted at an unknown frequency within a known range of frequencies and received, and, at the receiver, the range of frequencies is divided into plural frequency bands each of width less than the uncertainty in the transmission frequency of the data signal, with the presence of said data signal detected in at least one of said frequency bands and thereupon demodulated.Type: GrantFiled: November 25, 1998Date of Patent: February 18, 2003Inventors: Clive Russell Irving, David John Spreadbury, Colin Richard Smithers, Timothy Charles Mace
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Patent number: 6480553Abstract: A GFSK (Gaussian Frequency Shift Keying) radio transceiver is provided for ISM (Industrial Scientific and Medical) wideband communication. The GFSK radio transceiver includes a transmitter for modulating transmitted signal into RF signal, and a receiver for demodulating received signal into digital form. The transmitter includes a VCO for generating an oscillating signal serving as a carrier signal in the transmitter and a first local oscillating signal in the transmitter; and a variable-gain power amplifier, capable of being adjustable between two gain values, for amplifying the RF signal. The receiver includes a mixer for downconverting the received signal into a first IF signal by using the first local oscillating signal from the transmitter; and an IF demodulator for downconverting the first IF signal into a second IF signal by using a locally generated second local oscillating signal.Type: GrantFiled: November 13, 1998Date of Patent: November 12, 2002Assignee: Winbond Electronics Corp.Inventors: Hsiang-Te Ho, Hsing-Ya Chiang, Sheau-Chien Wang
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Patent number: 6470893Abstract: Devices and methods which sense a biopotential are disclosed. The sensed biopotential is used to modulate an output signal. The power of the output signal is limited so that the signal will attenuate within a predetermined distance. In one embodiment, a wireless ECG electrode has a transmitter in communication with the electrode. The transmitter outputs a signal which is modulated by the output of the electrode. The power of the signal is limited so that the signal will attenuate within a predetermined distance from a transmission point.Type: GrantFiled: May 15, 2000Date of Patent: October 29, 2002Inventor: Peter V. Boesen
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Patent number: 6459811Abstract: In a data transmission system, an encoder provides a bitstream having a sequence of frame segments, wherein each frame segment has a bit size which is limited by the encoder to a maximum bit size. A transmission channel is provided which has a channel rate sufficient to transmit a frame segment of maximum bit size within a frame interval. A burst transmitter receives the bitstream from the encoder and transmits each consecutive frame segment, at regular frame intervals, in a burst at the channel rate via the transmission channel, to provide a bursty bitstream over the transmission channel.Type: GrantFiled: April 1, 1999Date of Patent: October 1, 2002Assignee: Sarnoff CorporationInventor: Robert Norman Hurst, Jr.
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Patent number: 6438176Abstract: A GFSK modulator suitable for use in an RF communication system comprising a modular subsystem and a baseband processor subsystem which is implemented digitally. The baseband processor subsystem comprises a Gaussian filter, phase accumulator and cosine and sine look up tables. The baseband processor functions to convert an input data sequence into I and Q output signals. The I and Q signals are subsequently modulated by a quadrature modulator to yield a GFSK modulated signal which can then be amplified and placed into the channel. The response of the Gaussian filter is pre-calculated for all possible combinations of the input data and the results are quantized and stored in a look up table. The quantized phase results (either magnitude or differences), generated in response to the input data, are accumulated digitally and converted to I and Q signals.Type: GrantFiled: April 4, 2000Date of Patent: August 20, 2002Assignee: Texas Instruments IncorporatedInventors: Onn Haran, Haviv Ilan, Yaron Kaufmann
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Patent number: 6434194Abstract: A communication system provides robust, short range radio communications between battery operated devices by using ON-OFF-KEYED (OOK) modulation and either frequency shift keyed (FSK) modulation or pulse position/width modulation (PPM/PWM), in combination with a prescribed communications protocol. The system transmitter requires no local oscillator and is only active during actual communication, so that its current drain is not a significant factor in total battery life. Also, the receiver is active for only a small fraction of time. The need for large, complex and expensive filters is minimized by using a single IF band-pass filter in active form or passively in the form of a low cost ceramic filter such as those used in inexpensive transistor radios. The digital transmitter and receiver portions of the system are implemented by low cost, and ultra low power CMOS logic.Type: GrantFiled: November 3, 1998Date of Patent: August 13, 2002Assignee: Wherenet CorpInventors: John A. Eisenberg, Douglas C. Bowman, Huong M. Hang
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Publication number: 20020075092Abstract: A method and apparatus for generating digitally modulated signals in which a serial data stream of digital signals to be modulated (70) is provided, the serial data stream being converted into real and imaginary components (74) which are then converted into a complex polar signal (80) representing the serial data stream. A carrier of appropriate frequency is generated by an infinite impulse response filter (84,86) and the polar signal is mixed with the output of the infinite impulse response filter to provide a representation of the complex polar signal modulated at the frequency generated by the infinite impulse response filter (88). Subsequently the imaginary component of the resulting representation is stripped from the signal (90) and the real component of the resulting representation is applied to a digital to analog converter (92) to produce an analog version of the serial data stream.Type: ApplicationFiled: December 15, 2000Publication date: June 20, 2002Applicant: Motorola, Inc.Inventors: Randy L. Turcotte, Stephen Chihhung Ma, Matthew A. Ronning, Keith V. Warble, Peter O. Okrah
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Publication number: 20020063606Abstract: An image reject circuit comprises a local oscillator 26 for producing a local oscillator signal. A tunable phase shifting network 29 has inputs 1, 3 for receiving the local oscillator signal and producing an output in-phase (I) signal 13, 25 and an output quadrature (Q) signal 15, 27. A first amplitude detector 33 determines the amplitude of the output I signal, while a second amplitude detector 35 determines the amplitude of the output Q signal. A comparator 37 determines the difference between the amplitudes of the output I and Q signals, to produce a tuning signal for tuning the phase shifting network 29 to bring the difference between the amplitudes of the output I and Q signals towards a desired level. Preferably, the tunable phase shifting network 29 (shown in FIG. 4) comprises a combination of tunable capacitive, resistive and inductive elements.Type: ApplicationFiled: December 5, 2000Publication date: May 30, 2002Applicant: Telefonaktiebolaget L M EricssonInventor: Paulus Thomas Maria van Zeijl
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Patent number: 6392499Abstract: A frequency shift modulation circuit has a direct digital synthesizer DDS and a phase-locked loop PLL. DDS stores output signal frequency data in a plurality of registers. DDS selects the register storing the frequency data in accordance with a frequency shift keying FSK data signal whose voltage was controlled by a comparator. A signal output from DDS is input to PLL. PLL generates a signal whose phase is synchronized with the signal supplied from DDS, and outputs a frequency shift signal having a shift amount corresponding to the digital value of the FSK data signal. The FSK data signal is input via a balance adjustor to PLL so that a large frequency shift is possible. Since the frequency data is set to DDS, a stable modulation even for a low frequency is possible. In this manner, the frequency of an output signal can be stably shifted.Type: GrantFiled: April 20, 2000Date of Patent: May 21, 2002Assignee: Kabushiki Kaisha KenwoodInventor: Tetsuo Sato
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Patent number: 6349111Abstract: The present invention relates to a circuit for allocating a channel to a transmission between at least two modems that use an electric network as a medium for the transmission of a binary data flow. The circuit includes, on the receive side, a device for selecting a channel that is selected for having the best transmission level according to the energy received on several transmission channels. The transmission of the binary data flow occurs, at least at the beginning of each communication on the several channels.Type: GrantFiled: November 18, 1998Date of Patent: February 19, 2002Assignee: SGS-Thomson Microelectronics S.A.Inventor: Joël Huloux
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Patent number: 6349116Abstract: A non-propagating magnetic field-based communication system transmits and receives digital data within a limited coverage area environment. The system includes a compact transmitter unit, such as that contained in an ‘tracking’ tag affixed to an object, and a digital detector/demodulator unit. In order to generate and FSK-modulate a non-propagating magnetic field in accordance with modulation signals representative of the digital data, the transmitter unit contains a magnetic field coil and one or more capacitors controllably switched in circuit with the coil in accordance with the data, so as to change the resonant frequency of an inductor-capacitor transmitter resonant circuit. The receiver unit includes a magnetic field-sensing coil in circuit with a capacitor, to form a receiver resonant circuit that resonates at a frequency between the FSK frequencies modulated by the transmitter unit.Type: GrantFiled: October 12, 2000Date of Patent: February 19, 2002Assignee: Wherenet Corp.Inventors: Ronald J. Hash, Douglas C. Bowman
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Patent number: 6323767Abstract: This invention teaches a method and apparatus of LEDS, non volatile memory, an LCD, microcontrollers and a keypad to quickly determine the decoding status of EAS and SAME messages; a method and apparatus for the user to define the translation of these messages into custom text messages, abbreviations and different languages; and a method and apparatus for interfacing the decoded messages to alphanumeric paging, personal communication text messaging services, internet, email and remote LED signboards boards by hardware, modem and pager.Type: GrantFiled: June 8, 2000Date of Patent: November 27, 2001Inventor: Daniel R. Gropper
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Patent number: 6317009Abstract: The present invention teaches a system for selectably oscillating at a first or a second oscillating frequency. The system comprises an oscillator for providing an oscillating output. Moreover, the system comprises a switching device for selecting a first or a second impedance in response to a select signal having a voltage. Each of the first and second impedances are fixed independently of the select signal voltage such that the oscillating output oscillates at the first oscillating frequency when the first impedance is provided and oscillates at the second oscillating frequency when the second impedance is provided.Type: GrantFiled: April 16, 2001Date of Patent: November 13, 2001Assignee: Lear Automotive Dearborn, Inc.Inventor: John P. Hill
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Patent number: 6307441Abstract: A shape modulation transmit loop with digital frequency control permits spectral shaping of a digital pulse stream (12) by controlling the slew rate of the transition signal (16) between successive pulses. The loop is formed when the digital data stream is fed into an up/down counter (152) whose output is coupled to a programmable memory means (154), such as RAM, EEPROM, flash memory or similar electronic storage means. The output (108) of the programmable memory (154) forms a first input to an adder (112) which drives an accumulator (52) with specified steps. Values corresponding to the desired waveform (70) are stored in a lookup table (60) which is coupled to a digital-to-analog conversion circuit (64) which uses the values in the lookup table (60) to construct a sine wave output signal (70) corresponding to the frequency set by the current specified step of the up/down counter (152).Type: GrantFiled: December 31, 1998Date of Patent: October 23, 2001Assignee: Texas Instruments IncorporatedInventor: Claude Andrew Sharpe
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Publication number: 20010022540Abstract: The present invention teaches a system for selectably oscillating at a first or a second oscillating frequency. The system comprises an oscillator for providing an oscillating output. Moreover, the system comprises a switching device for selecting a first or a second impedance in response to a select signal having a voltage. Each of the first and second impedances are fixed independently of the select signal voltage such that the oscillating output oscillates at the first oscillating frequency when the first impedance is provided and oscillates at the second oscillating frequency when the second impedance is provided.Type: ApplicationFiled: April 16, 2001Publication date: September 20, 2001Applicant: UT Automotive Dearborn, Inc.Inventor: John P. Hill
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Patent number: 6288618Abstract: A cost-effective continuous phase logic-based modulator and demodulator are provided to allow communications using binary frequency shift keying (BFSK) as well as M-ary FSK techniques. The modulator of the 1-bit precision modem architecture is based on a 1-bit precision numerically controlled oscillator (NCO), which provides complete programmability with respect to a frequency of the 1-bit precision logic-based modulator and/or demodulator. The output of the 1-bit precision NCO is upconverted to an intermediate frequency using a simple logic function, i.e., XNOR logic. The undesirable portion of the upconverted signal may be suppressed using I/Q image rejection, and/or an appropriate bandpass filter may be used. A band limited, hard limited signal at the high IF is presented to the 1-bit precision demodulator as a receive IF signal, which is treated as a 1-bit quantization of the signal. The receive IF signal is digitally down-converted to a low IF signal to produce an alias signal at the low IF frequency.Type: GrantFiled: December 20, 1999Date of Patent: September 11, 2001Assignee: Agere Systems Guardian Corp.Inventors: Carl R. Stevenson, Yun Xiang Yuan
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Patent number: 6265948Abstract: A cost-effective continuous phase logic-based modulator and demodulator are provided to allow communications using binary frequency shift keying (BFSK) as well as M-ary FSK techniques. The modulator of the 1-bit precision modem architecture is based on a 1-bit precision numerically controlled oscillator (NCO), which provides complete programmability with respect to a frequency of the 1-bit precision logic-based modulator and/or demodulator. The 1-bit precision NCO includes an adder and a phase accumulator register which is clocked by a master clock signal. A two-input multiplexer has a single bit symbol value to generate BFSK, or larger input multiplexers can be implemented to provide M-ary FSK. The output of the 1-bit precision NCO is upconverted to an intermediate frequency using a simple logic function, i.e., XNOR logic. Alternatively, the intermediate frequency may be arrived at without the need for upconversion by directly utilizing a harmonic alias at a desired IF frequency.Type: GrantFiled: December 20, 1999Date of Patent: July 24, 2001Assignee: Agere Systems Guardian Corp.Inventor: Carl R. Stevenson
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Patent number: 6225873Abstract: The present invention teaches a system for selectably oscillating at a first or a second oscillating frequency. The system comprises an oscillator for providing an oscillating output. Moreover, the system comprises a switching device for selecting a first or a second impedance in response to a select signal having a voltage. Each of the first and second impedances is fixed independently of the select signal voltage such that the oscillating output oscillates at the first oscillating frequency when the first impedance is provided and oscillates at the second oscillating frequency when the second impedance is provided.Type: GrantFiled: December 1, 1995Date of Patent: May 1, 2001Assignee: Lear Automotive Dearborn, Inc.Inventor: John P. Hill
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Patent number: 6208696Abstract: A low power density radio system is provided using a simple FSK transmitter arranged to transmit very short bursts to a receiver at predetermined frequent intervals. Such a system can be used between a meter transponder and a reader in an AMR system to eliminate the need for a receiver in the transponder and still achieve extended battery life. The problems of detecting and demodulating the short burst are overcome by using a sample and hold circuit that detects a preamble signal of reversals to indicate the presence of the burst. The sample and hold circuit also provides the reference value to correct for the DC pedestal voltage that arises as a function of the transmitter and receiver frequency errors. The data signal that follows the preamble signal can then be detected, and is followed by a verifying signal as part of the signal burst. The burst signal is repeated at predetermined intervals and is preferably only {fraction (1/4000)} or less than the signal time interval.Type: GrantFiled: December 12, 1997Date of Patent: March 27, 2001Assignee: Ramar Technology LimitedInventor: Terence George Giles
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Patent number: 6188885Abstract: A user terminal provides communications to and from a radiotelephone communications system. This radiotelephone communications system supports communications with the user terminal at a first power level and paging to the user terminal at a second power level greater than the first power level. In addition, a page includes an indication when voice mail has been received at the radiotelephone communications system. In particular, the user terminal includes a transceiver, a processor, and a user interface. The transceiver receives communications from the radiotelephone communications system at the first power level, transmits communications to the radiotelephone communications system, and receives pages from the radiotelephone communications system at the second power level.Type: GrantFiled: March 16, 1998Date of Patent: February 13, 2001Assignee: Ericsson Inc.Inventors: Javor Kolev, Torbjorn Solve
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Patent number: 6185264Abstract: A transmitter for generating and transmitting frequency shift keying signals. The transmitter comprises a resonant circuit, a capacitor, a switch for coupling and decoupling the capacitor to the resonant circuit, a sensor and a controller. The controller includes an input for receiving a data signal. The controller actuates the switch to selectively couple the capacitor to the resonant circuit based on the state of the data signal. The sensor determines when the energy level in the capacitor is substantially zero and the controller synchronizes actuation of the switch with the substantially zero energy state of the capacitor. The transmitter also includes a circuit for efficiently supplying power to the resonant circuit in form the power pulses.Type: GrantFiled: December 17, 1997Date of Patent: February 6, 2001Inventor: Ove Kris Gashus
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Patent number: 6173017Abstract: The invention relates to a transit modulator for jittering a signal (Uin) comprising a memory (3), a clock generator (2) connected to said memory (3) and generating a jitter free input clock (T) as well as a further clock generator (5) connected to said memory (3) and generating a jittered output clock (Tj). It is the object of the invention to provide a transit modulator which allows any kind of signals and thus also non-binary digital signals to be jittered. This object is accomplished according to the invention by a transit modulator in which an A/D converter (1) is pre-connected and a D/A converter (4) is post-connected to said memory (3).Type: GrantFiled: November 26, 1997Date of Patent: January 9, 2001Assignee: Tektronix, Inc.Inventor: Freimut Marz
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Patent number: 6163229Abstract: A frequency generating circuit scales a warp range of a frequency signal. The frequency generating circuit includes a first frequency signal (10) having a first offset signal with a first frequency relationship to the first frequency signal, and a second frequency signal (14). A frequency scaling element (16) receives the first frequency signal (10) and second frequency signal and provides a third frequency signal, such that the third frequency signal includes the first offset signal having a second frequency relationship to the third signal. A switch (54), has a control input (74), a first input for receiving the first frequency signal, a second input operably coupled to the frequency scaling element (16, 42) for receiving the third frequency signal and an output (76) operably coupled to the first input or the second input dependent upon a control signal applied to the control input (74).Type: GrantFiled: December 10, 1997Date of Patent: December 19, 2000Assignee: Motorola, Inc.Inventors: Alfred Caspers, Manfred Mueller, Stefan Lichterfeld, Norbert Roettger
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Patent number: 6163568Abstract: An FM/FSK Transceiver for a wireless communications interface is disclosed which employs an offset phase lock loop which is accelerated into phase lock by a sweep signal to avoid data degradation, and which includes a feed forward compensation to accommodate a broadband response from DC to above 10 MHz in the exchange of information between computers, computers and peripheral equipments, and between peripheral equipments.Type: GrantFiled: September 8, 1998Date of Patent: December 19, 2000Assignee: Simtek CorporationInventors: James Lansford, Stephen M. Ernst
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Patent number: 6137842Abstract: A system determines the time difference of arrival of a frequency shift kd signal (FSK) source at two separate receiver sites. The system includes a first receiver located at a first site for generating a first series of signal samples in response to detecting an FSK signal from a FSK signal source. A second receiver located at a second site generates a second series of signal samples in response to detecting the FSK signal. A first computer estimates first frequency shift times of the FSK signal in response to receiving the first series of signal samples and a time reference signal, and generates a first output signal representing the first frequency shift times.Type: GrantFiled: November 28, 1997Date of Patent: October 24, 2000Assignee: The United States of America as represented by the Secretary of the NavyInventor: Peter C. Grossnickle
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Patent number: 6101213Abstract: A method, system, and computer program product for spread spectrum communication is provided using circular waveform shift-keying (CWSK). Circular waveform shift-keying is a modulation technique for conveying data over a spread spectrum channel. Data symbols are encoded in a circular time shift and/or circular frequency shift of a spread spectrum waveform. In a receiver, a CWSK synchronization stage and demodulator stage can be combined on a single fast convolution ASIC chip. Using CWSK modulation and demodulation, a secure, low-cost terminal is realized that can process calls on multiple spread spectrum channels in a hubless wireless network linking large numbers of low data rate users.Type: GrantFiled: March 21, 1997Date of Patent: August 8, 2000Assignee: Glynn Scientific, Inc.Inventor: Russell N. Van Allen
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Patent number: 6078226Abstract: A multiple frequency shifting oscillator that will provide a plurality of frequencies dependent upon a contents of an input shifting signal an input shifting signal is disclosed. The multiple frequency shifting oscillator has an amplifier with first input, a second input, which is coupled to a ground reference potential and an output. The multiple frequency shifting oscillator has a first impedance that is coupled between the first input of the amplifier and the ground reference potential, a second impedance that is coupled between the output of the amplifier and the ground reference potential, and a third impedance coupled between the output and the input of the amplifier. The multiple frequency shifting oscillator has a plurality of frequency shifting impedances that when selected will be coupled to the first impedance so as to shift the frequency of the multiple frequency shifting oscillator.Type: GrantFiled: February 2, 1998Date of Patent: June 20, 2000Assignee: Tritech Microelectronics, Ltd.Inventor: Aruna B. Ajjikuttira