Frequency Shift Keying Patents (Class 375/303)
  • Patent number: 7015749
    Abstract: A frequency discriminator for detecting phase shifts between sequential pulses in a frequency-shift keyed (FSK) signal having a nominal frequency, f. The frequency discriminator comprises: 1) a first current controlled delay line for receiving the FSK signal and delaying the FSK signal by a desired time delay to thereby produce a time-delayed FSK signal; 2) a multiplier for receiving and multiplying the FSK signal and the time-delayed FSK signal to thereby produce an output product signal proportional to a phase shift between said FSK signal and said time-delayed FSK signal; and 3) a delay locked loop comprising a second current controlled delay line substantially similar to the first current controlled delay line.
    Type: Grant
    Filed: February 8, 2002
    Date of Patent: March 21, 2006
    Assignee: National Semiconductor Corporation
    Inventors: Daniel R. Meacham, Ibrahim Yayla
  • Patent number: 6862313
    Abstract: 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: Grant
    Filed: April 18, 2002
    Date of Patent: March 1, 2005
    Assignee: Skyworks Solutions Inc.
    Inventors: John S. Walley, D. Vincent Laub, Norman J. Beamish
  • Patent number: 6785514
    Abstract: A method and radio station for transmitting information, wherein frequency channels of a frequency band are arranged in accordance with a first coarse raster system and a second fine raster system, the raster system being used, in particular, for performing an efficient frequency channel search and for the effective coding of the frequency channels.
    Type: Grant
    Filed: April 9, 2001
    Date of Patent: August 31, 2004
    Assignee: Siemens Aktiengesellschaft
    Inventor: Bernhard Raaf
  • Publication number: 20040125889
    Abstract: The RF communications system of the present invention wirelessly communicates data without encountering undue interference problems with other devices and complies with rules governing unlicensed, spectrum-sharing devices. In an example embodiment, a transmitter device includes a digital subsystem powered by a power supply that processes data from another device and a radio frequency (RF) sub-system that transmits the processed data using a frequency hopping scheme. The RF sub-system includes a microprocessor arrangement that ON-OFF keys a voltage controlled oscillator (VCO) and provides a frequency-hopping scheme. The VCO is coupled to a signal frequency spreading arrangement that spreads the signal to a predetermined transmission bandwidth, wherein the frequency spreading occurs during an ON state of the ON-OFF keying and the transmission bandwidth exceeds a reception bandwidth at which the signal will be decoded.
    Type: Application
    Filed: December 31, 2002
    Publication date: July 1, 2004
    Inventors: Scott Cumeralto, Richard Devries, Gary Larson
  • Publication number: 20040096009
    Abstract: A narrow band signal modulation method may include receiving digital data to be modulated, mapping the digital data to at least one of a plurality of different levels, and generating a carrier at a predetermined frequency. The method may further include generating a gating control signal every predetermined number of cycles of the carrier, outputting the at least one level for a predetermined portion of a carrier cycle responsive to the gating control signal, and outputting the carrier otherwise.
    Type: Application
    Filed: November 14, 2002
    Publication date: May 20, 2004
    Applicant: UNB Technologies, Inc.
    Inventor: Ronald J. Koval
  • Publication number: 20040096012
    Abstract: Data symbols in the training sequence are rotated at the transmitter end through a phase rotation factor which is specific for a given modulation type that is used. For blind modulation detection at the receiver end, the data symbols are derotated through different phase rotation factors, and a correlation function is formed between the sequences obtained in this way and the original training sequence. The type of modulation which is used is obtained from the phase rotation factor which produces a maximum for the correlation function.
    Type: Application
    Filed: November 12, 2003
    Publication date: May 20, 2004
    Inventor: Bin Yang
  • Patent number: 6690741
    Abstract: A data-modulated ultra wideband transmitter that modulates the phase, frequency, bandwidth, amplitude and/or attenuation of ultra-wideband (UWB) pulses. The transmitter confines or band-limits UWB signals within spectral limits for use in communication, positioning, and/or radar applications. One embodiment comprises a low-level UWB source (e.g., an impulse generator or time-gated oscillator (fixed or voltage-controlled)), a waveform adapter (e.g., digital or analog filter, pulse shaper, and/or voltage variable attenuator), a power amplifier, and an antenna to radiate a band-limited and/or modulated UWB or wideband signals. In a special case where the oscillator has zero frequency and outputs a DC bias, a low-level impulse generator impulse-excites a bandpass filter to produce an UWB signal having an adjustable center frequency and desired bandwidth based on a characteristic of the filter.
    Type: Grant
    Filed: November 22, 1999
    Date of Patent: February 10, 2004
    Assignee: Multispectral Solutions, Inc.
    Inventors: J. Frederick Larrick, Jr., Robert J. Fontana
  • Publication number: 20040001560
    Abstract: A transceiver includes a transmitter portion with an analog modulator that modulates data using frequency shift keyed (FSK) modulation techniques to increase efficiency, reduce power consumption, and reduce IC real estate in comparison to current digital FSK modulation circuits. The analog modulator comprises a loop that includes a pair of integrators and a pair of mixers. In at least one embodiment, the pair of mixers comprises switches that control a polarity of a modulated output signal that is produced to an up-conversion module for up-conversion to RF. The up-conversion module, then, when mixing the modulated output signal with a local oscillation signal, produces an output having one of two possible frequencies wherein the frequencies are a function of the polarity of the modulated output signal.
    Type: Application
    Filed: June 26, 2002
    Publication date: January 1, 2004
    Inventor: Hooman Darabi
  • Publication number: 20030223511
    Abstract: A waveform having an amplitude that varies to thereby represent corresponding data values is dithered to further shape the waveform so that use of the dithered waveform to create a corresponding FSK signal will result in a signal having a smoothed frequency domain profile. In various embodiments, the waveform amplitude is varied with respect to periodicity of variation, extent of variation, and duration of variation.
    Type: Application
    Filed: May 30, 2002
    Publication date: December 4, 2003
    Inventors: Gary Schulz, Chris Fay
  • Publication number: 20030206602
    Abstract: A multivalued FSK modulation system is provided in which when data to be transmitted is multivalued and transmitted/received, the detection level is different every symbol. When a two-valued signal is transmitted as one symbol, data (11), (01), (00) and (10) are previously set to be, for example, a shift of −6, a shift of +6, a shift of +2, and a shift of −2, respectively. When data to be input next is (00), mapping is performed so as to provide a sign weight of +2 from the sign weight at the position of current data. When the data to be input next is (10), mapping is performed so as to provide a sign weight of −2 from the position of the current sign weight. Thus, even if data of the same level is input, signals can be always detected in different levels, so that the sign detection point is not specified erroneously.
    Type: Application
    Filed: April 30, 2003
    Publication date: November 6, 2003
    Inventor: Michio Yamamoto
  • Patent number: 6600382
    Abstract: A phase modulator for direct wideband linear phase modulation of a microwave continuous wave carrier signal which is suitable for many analog and digital phase or frequency modulation techniques. Linear phase modulation range in excess of 360 degrees is provided as a result of linear variation in the modulating signal. A conditioned baseband modulating signal is injected into a highly linear fractional range phase shifter, operating at a subharmonic of the desired output frequency. A nonlinear circuit is used to perform frequency and instantaneous phase multiplication, thus expanding the linear phase modulation range to greater than 360 degrees at the desired output frequency. With special conditioning of the baseband modulating signal, the phase modulator can be made frequency agile in ultra-small frequency steps, without requiring a stable, frequency agile reference signal or frequency synthesizer.
    Type: Grant
    Filed: March 14, 2000
    Date of Patent: July 29, 2003
    Assignee: Telecommunications Research Laboratories
    Inventor: David M. Klymyshyn
  • Patent number: 6546060
    Abstract: A direct modulating frequency shift keying transmitter for multi channel access is constructed so that a transmission signal from a voltage controlled oscillator (VCO) in a phase lock loop frequency synthesizer is output through a buffer amplifier and a transmitting power amplifier, and a modulation signal is applied to the VCO. In the transmitter, in order to cancel instantaneous deviation of a transmission frequency due to ON of the transmitting power amplifier, an ON/OFF control signal is applied to the transmitting power amplifier.
    Type: Grant
    Filed: January 19, 1999
    Date of Patent: April 8, 2003
    Assignee: General Research of Electronics, Inc.
    Inventor: Kazuo Kawai
  • Publication number: 20030043931
    Abstract: An impulse radio communications system using one or more subcarriers to communicate information from an impulse radio transmitter to an impulse radio receiver. The impulse radio communication system is an ultrawide-band time domain system. The use of subcarriers provides impulse radio transmissions added channelization, smoothing and fidelity. Subcarriers of different frequencies or waveforms can be used to add channelization of impulse radio signals. Thus, an impulse radio link can communicate many independent channels simultaneously by employing different subcarriers for each channel. The impulse radio uses modulated subcarrier(s) for time positioning a periodic timing signal or a coded timing signal. Alternatively, the coded timing signal can be summed or mixed with the modulated subcarrier(s) and the resultant signal is used to time modulate the periodic timing signal. Direct digital modulation of data is another form of subcarrier modulation for impulse radio signals.
    Type: Application
    Filed: July 17, 2002
    Publication date: March 6, 2003
    Applicant: Pulson Communications Corporation, Inc.
    Inventors: Larry W. Fullerton, Ivan A. Cowie
  • Publication number: 20030012260
    Abstract: 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: Application
    Filed: April 18, 2002
    Publication date: January 16, 2003
    Inventors: John S. Walley, D. Vincent Laub, Norman J. Beamish
  • Publication number: 20030007570
    Abstract: The present invention relates to a technique for modulating a signal to be transmitted by multiple channel frequency shift keying, transmitting the same through a power line and then demodulating it easily by frequency conversion. By the multiple channel frequency shift keying (FSK) modulation, attenuation or distortion caused by noise and multi-path fading in a power line communication channel can be prevented, and the performance for phase response characteristics can be improved.
    Type: Application
    Filed: January 23, 2002
    Publication date: January 9, 2003
    Applicant: Xeline Co., Ltd.
    Inventors: Jin-Tae Kim, Tae-Sang Yoo, Ji-Hyun Kim, Se-Yong Lee
  • Publication number: 20020196865
    Abstract: Cycle-by-cycle synchronous waveform shaping is provided for by filtering and combining of square and/or impulse shaped signals. Specifically, a plurality of first square shaped signals is generated and filtered using at least one first filter to produce at least one filtered signal. A plurality of second square shaped signals is generated and filtered using at least one second filter to produce at least one second filtered signal. The at least one first and at least one second filtered signals are combined to produce a continuous shaped waveform having a characteristic shape within each of a plurality of data periods defining a data rate. Alternatively, at least one impulse signal having a plurality of sinusoidal impulses each comprising a positive impulse and a negative impulse is generated. The at least one impulse signal is filtered using at least one filter to produce the continuous shaped waveform.
    Type: Application
    Filed: March 8, 2002
    Publication date: December 26, 2002
    Applicant: The National University of Singapore
    Inventor: Wei Kwek Soh
  • Publication number: 20020168026
    Abstract: 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: Application
    Filed: March 6, 2001
    Publication date: November 14, 2002
    Inventor: Ramin Khoini-Poorfard
  • Patent number: 6480553
    Abstract: 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: Grant
    Filed: November 13, 1998
    Date of Patent: November 12, 2002
    Assignee: Winbond Electronics Corp.
    Inventors: Hsiang-Te Ho, Hsing-Ya Chiang, Sheau-Chien Wang
  • Publication number: 20020163976
    Abstract: In the known methods for transmitting data, the voltage of the modulation signal changes a plurality of times within one bit, or the voltage value of the modulation signal is determined by the significance of the bit.
    Type: Application
    Filed: April 26, 2002
    Publication date: November 7, 2002
    Applicant: ATMEL Germany GmbH
    Inventor: Udo Karthaus
  • Publication number: 20020131527
    Abstract: A method for photonic wavelength shifting and stabilization is described. The method receives a photonic signal, comprised of one or more channels, and provides a wavelength shifted, stabilized, and channelized photonic signal. Data encoding is also supported. A modulation synthesizer provides a modulation waveform embedded with the shifting, stabilization and data encoding mechanisms. A variety of modulation techniques are supported. The modulation waveform is optimized for the particular modulation technique. A wavelength error detector provides feedback to the modulation synthesizer. The error signal is used to stabilize the photonic signal and correct channel wavelength errors. Fixed wavelength channels and spread spectrum channels are supported.
    Type: Application
    Filed: March 16, 2001
    Publication date: September 19, 2002
    Inventors: Michael H. Myers, Charles D. Melville, Clark C. Guest
  • Publication number: 20020131526
    Abstract: An apparatus for photonic wavelength shifting and stabilization is described. The apparatus receives a photonic signal, comprised of one or more channels, and provides a wavelength shifted, stabilized, and channelized photonic signal. Data encoding is also supported. A modulation synthesizer provides a modulation waveform embedded with the shifting, stabilization and data encoding mechanisms. A variety of modulation devices are supported. The modulation waveform is optimized for the particular modulation device. A wavelength error detector provides feedback to the modulation synthesizer. The error signal is used to stabilize the photonic signal and correct channel wavelength errors. Fixed wavelength channels and spread spectrum channels are supported.
    Type: Application
    Filed: March 16, 2001
    Publication date: September 19, 2002
    Inventors: Michael H. Myers, Charles D. Melville, Clark C. Guest
  • Patent number: 6452461
    Abstract: A high-speed power-efficient coded M-ary Frequency-Shift Keying (M-ary FSK) modulator. The modulator includes a coding logic, which generates (M/2) Gray code signals in accordance with an (N−1) bits control signal; and (M/2) switching oscillators. Each switching oscillator includes: a composite crystal resonator with a first end and a second end; a first switch, which is controlled by Gray code signals, with one end connected to the first end of the composite crystal resonator, and the other end grounded via an equivalent negative resistance circuit; a second switch, which is controlled by serial data, with one end connected to the second end of the composite crystal resonator, and the other end grounded; and a capacitor, with one end connected to the second end of the composite crystal resonator, and the other end grounded.
    Type: Grant
    Filed: July 11, 2001
    Date of Patent: September 17, 2002
    Assignee: Tricome Microwave Electronics Corp.
    Inventors: Ching-Hsiang Su, Ching-Kuang Tzuang
  • Patent number: 6449317
    Abstract: The present invention is a method and system for processing communication signals in a wireless telecommunication system having at least two subscriber units. The subscriber units communicate with each other through a selected band of radio frequencies over a plurality of radio frequency channels. The system generates a fixed based radio frequency signal and a digital intermediate frequency signal. The fixed based radio frequency signal and the digital intermediate frequency signal are then combined to produce a carrier signal which is communicated between the at least two subscribers.
    Type: Grant
    Filed: June 13, 2000
    Date of Patent: September 10, 2002
    Assignee: Interdigital Technology Corporation
    Inventors: David Norton Critchlow, Moshe Yehushua, Graham Martin Avis, Wade Lyle Heimbigner, Karle Joseph Johnson, George Alan Wiley
  • Patent number: 6438176
    Abstract: 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: Grant
    Filed: April 4, 2000
    Date of Patent: August 20, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Onn Haran, Haviv Ilan, Yaron Kaufmann
  • Patent number: 6434135
    Abstract: The invention reduces transient peaks in signals transmitted in CDMA communication systems. A plurality of spread spectrum data signals are combined into a combined signal having fluctuating power level corresponding to the combination of the data signals. The combined signal is modulated to produce an RF signal for transmission. The average power of the combined signal is measured over a selected time period. The combined signal power level is adaptively limited to a calculated power level based at least in part on the measured power.
    Type: Grant
    Filed: August 31, 1999
    Date of Patent: August 13, 2002
    Assignee: Interdigital Technology Corporation
    Inventors: Fatih M. Ozluturk, Brian Kiernan
  • Patent number: 6418174
    Abstract: The present invention provides an FSK modulation circuit and technique that controls a prescaler to generate an FSK output. In particular, a VCO output is sent to a prescaler controlled by a modulus control signal. The modulus control signal contains a series of pulses having a first duty cycle to effect a mark frequency and a second duty cycle to effect a space frequency. During a given cycle, the prescaler divides the VCO output frequency by two different divisors. The resulting frequency is compared with a reference frequency using a phase detector. Changing the duty cycle of the modulus control signal controlling the prescaler causes the VCO to provide a corresponding, synthesized frequency from the VCO for FSK modulation.
    Type: Grant
    Filed: February 19, 1999
    Date of Patent: July 9, 2002
    Assignee: RF Micro Devices, Inc.
    Inventor: Mike Benedict
  • Patent number: 6411646
    Abstract: 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 bandpass or lowpass filter has an input coupled to the analog output of the digital to analog converter and has a filtered output. 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. The adder produces a summed output. 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.
    Type: Grant
    Filed: June 30, 1998
    Date of Patent: June 25, 2002
    Assignee: Conexant Systems, Inc.
    Inventors: John S. Walley, D. Vincent Laub, Norman J. Beamish
  • Patent number: 6396355
    Abstract: A signal generator includes an oscillator, a phase locked loop and a fractional divider. The oscillator is configured to provide an output signal. The phase locked loop is configured to receive the output signal and to provide a tuning signal to the oscillator. The phase locked loop has a phase detector configured to receive the output signal, to compare the output signal to a reference signal, and to provide the tuning signal to the oscillator based on the comparison. The fractional divider is outside of the phase locked loop and is configured to generate the reference signal.
    Type: Grant
    Filed: April 12, 2000
    Date of Patent: May 28, 2002
    Assignee: Rockwell Collins, Inc.
    Inventor: Phillip J. Rezin
  • Patent number: 6392499
    Abstract: 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: Grant
    Filed: April 20, 2000
    Date of Patent: May 21, 2002
    Assignee: Kabushiki Kaisha Kenwood
    Inventor: Tetsuo Sato
  • Patent number: 6366772
    Abstract: A method of communicating FSK-modulated Caller ID signals through a network incompatible to the transmission of these signals is presented. A first network component couples between the incompatible network and a Central Office, and a second network component couples between the incompatible network and the telephone. In one embodiment, the call flow proceeds until the second network component would ring the line of the called party. The second network component seizes the line but does not apply a ringing signal. The second network component continues with the call flow as though the second network component had entered the silent interval after the first ring cycle at the called party. Subsequently, the CO transmits the FSK Caller ID information to the first network component which detects the FSK transmission and converts it into an out-of-band message and transmits the out-of-band message over the incompatible network to the second network component.
    Type: Grant
    Filed: July 22, 1999
    Date of Patent: April 2, 2002
    Assignee: Xircom Wireless, Inc.
    Inventor: Jill C. Arnson
  • Patent number: 6317009
    Abstract: 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: Grant
    Filed: April 16, 2001
    Date of Patent: November 13, 2001
    Assignee: Lear Automotive Dearborn, Inc.
    Inventor: John P. Hill
  • Patent number: 6307441
    Abstract: 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: Grant
    Filed: December 31, 1998
    Date of Patent: October 23, 2001
    Assignee: Texas Instruments Incorporated
    Inventor: Claude Andrew Sharpe
  • Publication number: 20010022540
    Abstract: 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: Application
    Filed: April 16, 2001
    Publication date: September 20, 2001
    Applicant: UT Automotive Dearborn, Inc.
    Inventor: John P. Hill
  • Patent number: 6289056
    Abstract: In a broadband multicarrier modulator, all processing within a modulator is replaced by a pre-computed table so that a modulated signal can be produced as a function of the modulating signal merely by reading the table. The carrier frequency of the modulator is even programmable. The size of the pre-computed table is reduced by using an automation. With this automation the address for reading the table at a given time depends on preceding values of the modulating signal. By reading the table on a time sharing basis it is even possible, with a single modulator, to perform the work of several modulators. A multicarrier modulator is then easily implemented.
    Type: Grant
    Filed: April 1, 1999
    Date of Patent: September 11, 2001
    Assignee: Alcatel
    Inventor: Luc Dartois
  • Patent number: 6282246
    Abstract: A frequency modulation method and modem unit for a frequency modulation using a common filter which uses a large number of carrier frequencies include a frequency-shifting unit for subjecting an input data to a frequency shift corresponding to a binary data value, a filter for limiting an output obtained by the frequency-shifting unit to a common band, and a modulation unit for frequency-modulating an output obtained by the filter, by a carrier frequency having an intermediate value of the frequencies respectively corresponding to the binary data values.
    Type: Grant
    Filed: October 23, 1997
    Date of Patent: August 28, 2001
    Assignee: Fujitsu Limited
    Inventors: Takashi Kaku, Ryoji Okita
  • Patent number: 6282236
    Abstract: Various modem designs are described, along with systems that use the modem designs for communicating data between a large number of remote locations and one or more central locations preferably over CATV. One aspect features a modem having a transmitter which uses a state machine and digital waveform signals stored in a memory to create a modulated signal. Another aspect features a modem having a receiver which uses a digital correlator including an SRAM for detecting a bipolar phase shift keyed signal. Still another aspect features a modem comprising an oscillator circuit having a feedback loop, wherein the feedback loop utilizes a downlink signal, and a protection circuit which prevents a malfunction in the modem from causing system-wide shutdown.
    Type: Grant
    Filed: April 3, 1997
    Date of Patent: August 28, 2001
    Assignee: Lucent Technologies, Inc.
    Inventor: Thomas Lynn Carter, IV
  • Patent number: 6225873
    Abstract: 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: Grant
    Filed: December 1, 1995
    Date of Patent: May 1, 2001
    Assignee: Lear Automotive Dearborn, Inc.
    Inventor: John P. Hill
  • Patent number: 6185264
    Abstract: 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: Grant
    Filed: December 17, 1997
    Date of Patent: February 6, 2001
    Inventor: Ove Kris Gashus
  • Patent number: 6157271
    Abstract: A direct modulation phase lock loop (PLL) a voltage controlled oscillator (VCO) (114). A divider (118) has a first divider input coupled to the VCO and a second divider input to receive a modulation inducing divisor sequence. A phase detector (102) has a first detector input coupled to the divider to receive the output thereof, and a second detector input to receive a reference input. A tuning circuit (306, 406) is coupled to the phase detector and the VCO, the tuning circuit responsive to a variable DC reference potential such that the tuning circuit has a frequency response that is constant over the modulation bandwidth whereby the PLL is a type 1 PLL with low modulation distortion.
    Type: Grant
    Filed: November 23, 1998
    Date of Patent: December 5, 2000
    Assignee: Motorola, Inc.
    Inventors: Gregory Redmond Black, Louis Michael Nigra, Michael Edward Denzin
  • Patent number: 6101213
    Abstract: 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: Grant
    Filed: March 21, 1997
    Date of Patent: August 8, 2000
    Assignee: Glynn Scientific, Inc.
    Inventor: Russell N. Van Allen
  • Patent number: 6034990
    Abstract: A digital radio transmission and reception system capable of preventing shift of carrier by fading through receiving a modulated signal radio-transmitted, and then directly demodulating the signal.
    Type: Grant
    Filed: August 25, 1997
    Date of Patent: March 7, 2000
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Keun-Mo Kang
  • Patent number: 6008703
    Abstract: A digital compensation filtering technique is provided that enables indirect phase locked loop modulation with a digital modulation data stream having a bandwidth that exceeds, perhaps by an order of magnitude, the bandwidth characteristic of the phase locked loop. A modulation data receiver is provided for receiving from a modulation source digital input modulation data having a bandwidth that exceeds the cutoff frequency characteristic of the phase locked loop frequency response. A digital processor is coupled to the modulation data receiver for digitally processing the input modulation data to amplify modulation data at frequencies higher than the phase locked loop cutoff frequency.
    Type: Grant
    Filed: January 31, 1997
    Date of Patent: December 28, 1999
    Assignee: Massachusetts Institute of Technology
    Inventors: Michael H. Perrott, Charles G. Sodini, Anantha P. Chandrakasan
  • Patent number: 6002304
    Abstract: A modulation system is provided with a data analyzer detecting input of a modulated data and a modulation clock signal and latching and detecting an edge of the modulated data, in response to the modulated data and the modulation clock signal, a signal controller, responsive to an output of the data analyzer, carrying out an operation process with respect to the frequency deviation data and carrying out one of a frequency deviation amplitude control operation and a frequency deviation time control operation, a digital-to-analog converter converting an output of the signal controller into an analog signal, and a transmitting unit transmitting an output of the digital-to-analog converter.
    Type: Grant
    Filed: April 23, 1998
    Date of Patent: December 14, 1999
    Assignee: Fujitsu Limited
    Inventor: Satoshi Kuroki
  • Patent number: 5999577
    Abstract: A circuit is provided by which in the case of the transmission of a short packet signal through an FSK transmission channel having a frequency error for transmission and reception, directly from one shaped rectangular pulse of a frequency detected bit synchronization signal having a DC offset (this pulse including a bias distortion as it is) a clock signal can be generated indicating the points of time when the base-band signal passes through its center level and the point of time when it arrives its maximum or minimum value (data sampling points of time). This invention utilizes the fact that the bit synchronization signal is in the form of a sine wave because it has been band limited.
    Type: Grant
    Filed: June 19, 1997
    Date of Patent: December 7, 1999
    Assignee: General Research of Electronics, Inc.
    Inventor: Kazuo Kawai
  • Patent number: 5945885
    Abstract: A digital baseband modulator having a flexible architecture that is readily adaptible to a variety of digital modulation types is provided. A symbol builder maps the input data to a series of modulation states corresponding to data symbols that are represented as state indexes. A pair of digital filters accepts the state indexes being generated by the symbol builder to provide both up-sampling and filtering functions. The digital filters are implemented using random access memory (RAM) to implement blocks of interpolating look-up multipliers which may be readily configured between fast, normal, and long modes. The filtered output data from the digital filters is provided to a resampler that converts the filtered output data to an output sample rate that corresponds to the sample rate of output DACs and corresponding analog low pass filters.
    Type: Grant
    Filed: March 5, 1998
    Date of Patent: August 31, 1999
    Assignee: Hewlett-Packard Company
    Inventors: David J Schwartz, Alan R Bloom, William J. Anklam
  • Patent number: 5912926
    Abstract: 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 modulating apparatus comprises a modulator having an input and an output and is responsive to an input modulation signal applied to its input for generating at its output the frequency modulated signal at a center frequency dependent on a quiescent voltage appearing at its input. A circuit is provided for sampling and storing a value of the quiescent voltage. An addressable memory stores a plurality of offsets. A programmable adding circuit adds a downloaded offset voltage to the stored value of the quiescent voltage to output a high modulation voltage. A programmable subtracting circuit subtracts a downloaded offset voltage from the stored value of the quiescent voltage to provide a low modulation voltage.
    Type: Grant
    Filed: September 10, 1996
    Date of Patent: June 15, 1999
    Assignee: Norand Corporation
    Inventors: Steven E. Koenck, Ronald L. Mahany, William W. Frede
  • Patent number: 5905413
    Abstract: A digital modulator capable of obtaining a high FM modulation index and reducing the quantization noise without increasing the sampling frequency of an A/D converter of input voice. A phase variation .phi.(Ts) of the digital data (Ts is the sampling period) produced on the basis of the output from the A/D converter is divided by a predetermined integer N (N>1) by a divider, and is fed to an integrator. The integrator integrates the divided phase variation .phi.(Ts)/N for every time interval Ts/N, thereby producing a phase component .phi.(t) of the complex envelope of the modulation signal. The phase component .phi.(t) is resolved into cosine and sine components at the time interval Ts/N. The cosine and sine signals are D/A converted into analog signals which are quadrature modulated by a quadrature modulator.
    Type: Grant
    Filed: April 30, 1998
    Date of Patent: May 18, 1999
    Assignee: OKI Electric Industry Co., Ltd.
    Inventors: Tatsumasa Yoshida, Ryoichi Miyamoto
  • Patent number: 5889443
    Abstract: A frequency synthesizing circuit has an input on which a bit flow is received, and an output on which a data-modulated output signal is supplied. The circuit moreover comprises a crystal oscillator supplying a reference clock signal, a phase-locked loop (PLL) having a VCO and a phase detector. The phase detector compares the data-modulated output signal with the reference clock signal and, in response to this, supplies an error signal by means of which the VCO output frequency is controlled. A compensation circuit, which receives a measure of the bit flow received, compensates the data-modulated output signal in the phase-locked loop in response to this before it is supplied to the phase detector.
    Type: Grant
    Filed: September 10, 1997
    Date of Patent: March 30, 1999
    Assignee: Nokia Mobile Phones, Ltd
    Inventor: Klaus J.o slashed.rgensen
  • Patent number: 5852636
    Abstract: A method and a transmitter system is provided for modulating binary information on a frequency shift keying carrier in a very narrow band. Phase reversal keying is initially used to create a carrier. The transmitter of the present invention generates a carrier signal by modulating a reference signal and a control signal having two frequencies representing the binary data to be transmitted. The resulting phase reversal carrier signal is processed by high order filtering such that the output of the transmitter provides a frequency shift keyed carrier at very close frequencies. The resulting carrier signal may, at the receiver, be processed by very narrow band filtering so as to create a communication system which will use only a small part of the available spectrum.
    Type: Grant
    Filed: August 8, 1997
    Date of Patent: December 22, 1998
    Assignee: Serge Mathieu
    Inventors: Serge Mathieu, Dominic Tremblay
  • Patent number: 5841364
    Abstract: A transponder unit (10) includes an N cycle counter (30) and an M cycle counter (28). The N cycle counter (30) has a different cycle value than the M cycle counter (28). During the transmission of information from the transponder unit (10), the duration for data bits having a binary zero value is controlled by the N cycle counter (30). The duration of data bits having a binary one value is controlled by the M cycle counter (28). The use of different cycle values within the N cycle counter (30) and the M cycle counter (28) allows for the transmission of binary one and binary zero data bits having the same bit length despite different frequencies representing the binary one and binary zero bits respectively.
    Type: Grant
    Filed: March 13, 1997
    Date of Patent: November 24, 1998
    Assignee: Texas Instruments Incorporated
    Inventors: Andreas Hagl, Josef H. Schuermann