Frequency Shift Keying Patents (Class 375/303)
  • Patent number: 7702038
    Abstract: A radio frequency (RF) receiver for receiving transmissions of different modulations includes cycling between a first mode for receiving transmissions of a first modulation that occurs frequently and a second mode for receiving transmission of a second modulation that occurs infrequently. The example RF receiver is cycled between a first modulation for receiving a frequency shift keyed (FSK) transmission from a tire pressure monitoring (TPM) system and a second modulation for receiving an amplitude shift keyed (ASK) transmission from a remote keyless entry (RKE) system. The RF receiver cycles between different modulations to detect the most frequent FSK modulated transmissions while also detecting and receiving the relatively infrequent ASK modulated RKE transmissions without an undesirable delay.
    Type: Grant
    Filed: September 7, 2006
    Date of Patent: April 20, 2010
    Assignee: Continental Automotive Systems US, Inc.
    Inventors: John R. Anderson, Wayne Wang
  • Patent number: 7693235
    Abstract: A concatenated coding scheme, using an outer coder, interleaver, and the inner coder inherent in an FQPSK signal to form a coded FQPSK signal. The inner coder is modified to enable interative decoding of the outer code.
    Type: Grant
    Filed: August 31, 2006
    Date of Patent: April 6, 2010
    Assignee: California Institute of Technology
    Inventors: Marvin K. Simon, Dariush Divsalar
  • Patent number: 7688912
    Abstract: The present invention reduces adjacent channel interference for a wireless peripheral device. A direct digital synthesizer generates a waveform having intermediate angular changes during a transition time between symbol intervals. After the transition time, the direct digital synthesizer generates the waveform with an angular value that corresponds to the symbol being transmitted. In an exemplary embodiment, a generated waveform is characterized by one of two designated frequencies in response to a value of an input information bit. The waveform is further characterized by at least one intermediate frequency during a transition time between a change of the designated frequency. Another embodiment of the invention utilizes phase changes rather than frequency changes during reduce adjacent channel interference. With another aspect of the invention, methods are provided to determine waveform parameters for reducing adjacent channel power (ACP) to a maximum level of interference.
    Type: Grant
    Filed: December 11, 2006
    Date of Patent: March 30, 2010
    Assignee: Microsoft Corporation
    Inventor: Mihai Albulet
  • Patent number: 7676008
    Abstract: A system and method for obtaining a frequency error estimate representing the difference between a reference frequency and the frequency of a space-time transmit diversity signal is disclosed herein. The method includes taking the correlation of total sums, comprised of partial sums taken in defined first and second intervals, to represent the frequency error as the imaginary component of the correlation function.
    Type: Grant
    Filed: July 12, 2007
    Date of Patent: March 9, 2010
    Assignee: Research In Motion Limited
    Inventors: Xin Jin, Runbo Fu, Jorgen S. Nielsen
  • Publication number: 20100052869
    Abstract: Transponders are disclosed that are configurable to operate in an HDX mode and/or an FDX-B mode and that use a switchable load impedance across the transponders' resonant antenna circuit to induce amplitude and/or frequency modulation. An RF level detection circuit determines when the instantaneous activation signal strength is sufficient to support monoplex, multiplex, and diplex operation. A non-volatile memory stores identification data coded in HDX and FDX-B formats. One embodiment of the invention includes an inductive antenna including two terminals connected to tag circuitry, where the inductive antenna forms a resonant antenna circuit tuned to resonate at the frequency of the activation signal.
    Type: Application
    Filed: September 4, 2009
    Publication date: March 4, 2010
    Inventor: Robert Stewart
  • Patent number: 7667551
    Abstract: A frequency shift keying modulator having sigma-delta modulated phase rotator is disclosed, which includes a phase-locked loop for generating a voltage-controlled signal; a multi-phase generator for receiving the voltage-controlled signal and generating N phase-shift signals having same frequency according to the voltage-controlled signal, the N phase-shift signals having a same phase shift between the phase-shift signals adjacent to each other; a sigma-delta modulator for receiving transmission data and randomly outputting a modulation bit at a modulation clock according to the transmission data; and a phase rotator for receiving the N phase-shift signals and selectively outputting one of the N phase-shift signals and a frequency-divided signal according to the modulation bit, wherein the frequency of the frequency-divided signal is 1 / ( 1 + n N ) of the frequency of any one of the N phase-shift signals.
    Type: Grant
    Filed: May 27, 2008
    Date of Patent: February 23, 2010
    Assignee: National Taiwan University
    Inventors: Tsung-Hsin Lin, Yao-Hong Liu
  • Patent number: 7627046
    Abstract: Method and apparatus for peak-to-amplitude ratio reduction are described. A data carrying signal waveform with sub-carrier signals (S1-1 through S1-M) is obtained. An initial peak reduction waveform (S2(m)) is obtained by selection of a portion of the sub-carrier signals (S1-1 through S1-M) for non-data carrying. The initial peak reduction waveform (S2(m)) is refined by at least one recursive iteration which combines the initial peak reduction waveform (S2(m)) with a circularly time-shifted version thereof to obtain a resultant peak reduction waveform having a peak side lobe amplitude less than that of the initial peak reduction waveform (S2(m)).
    Type: Grant
    Filed: April 29, 2005
    Date of Patent: December 1, 2009
    Assignee: Xilinx, Inc.
    Inventors: Christopher H. Dick, Frederic J. Harris
  • Patent number: 7627059
    Abstract: A symbol detector for an OFDM receiver determines the correlation of corresponding samples of at least two received preamble symbol samples, one of the samples delayed a predetermined duration with respect to the other; determines a timing metric based on the correlation results; detects multiple peaks in the timing metric; indicates a symbol detection based on the multiple peaks detected in the timing metric; and gets a refined CFO estimation using averaging the phase information across these multiple peaks.
    Type: Grant
    Filed: April 5, 2005
    Date of Patent: December 1, 2009
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Huaning Niu, Chiu Ngo
  • Publication number: 20090268847
    Abstract: A method for calibrating a phase locked loop begins by determining a gain offset of a voltage controlled oscillator of the phase locked loop. The processing then continues by adjusting current of a charge pump of the phase locked loop based on the gain offset.
    Type: Application
    Filed: May 5, 2009
    Publication date: October 29, 2009
    Applicant: Broadcom Corporation
    Inventors: Henrik T. Jensen, Hea Joung Kim
  • Patent number: 7606321
    Abstract: The system and method enable simpler analog processing in a transmitter by reducing the number of bits in a digital signal through delta sigma modulation. Selection of current sources in a digital to analog converter of the transmitter is done using a randomization circuit.
    Type: Grant
    Filed: June 29, 2004
    Date of Patent: October 20, 2009
    Assignee: Broadcom Corporation
    Inventor: Meng-An Pan
  • Patent number: 7599418
    Abstract: A method and system for generating a frequency hopping electromagnetic signal based on a baseband data signal includes a frequency hopping pre-compensator. The frequency hopping pre-compensator determines a frequency hopping pre-compensation signal based on a desired frequency hopping sequence. The frequency hopping pre-compensation signal is combined with the baseband data signal to generate a pre-compensated baseband signal. An RF modulator modulates an RF carrier in accordance with the pre-compensated baseband signal to generate a modulated, frequency hopping RF carrier signal. An amplifier may then amplify the RF carrier signal as desired.
    Type: Grant
    Filed: February 16, 2006
    Date of Patent: October 6, 2009
    Assignee: Pine Valley Investments, Inc.
    Inventor: Walid Khairy Mohamed Ahmed
  • Publication number: 20090193309
    Abstract: There are provided a transmission and reception device having a function for correcting a data error in a communication path. In the transmission device, a redundant bit addition unit adds a redundant bit to each data bit which has been divided by one bit by a division unit; and an interleaver performs interleave. The transmission device transmits a signal which has been subjected to FM modulation by an FM modulation unit. In the reception device, a symbol decision unit performs a symbol decision at a Nyquist point for a signal which has been FM-demodulated by an FM demodulation unit; a bit conversion unit performs bit conversion according to the result of symbol decision; and a frame recovery unit deletes the redundant bit added by the redundant bit addition unit of the transmission device, from the bit string de-interleaved by a de-interleaver. Thus, it is possible to surely perform an error correction with a simple configuration even when the communication state is not in a preferable environment.
    Type: Application
    Filed: April 7, 2009
    Publication date: July 30, 2009
    Applicant: KABUSHIKI KAISHA KENWOOD
    Inventor: Taichi MAJIMA
  • Patent number: 7564923
    Abstract: A transmitter digital signal processor (DSP) circuit has a transmit frequency represented by n-bit data output from a look up table (LUT). The n-bit data is outputted to an n-bit accumulator structured to overflow at a rate based on the output n-bit data to output a phase. The circuit further has device structured to add an n-bit signed constant to the accumulator to offset the frequency represented by the n-bit data output from the LUT. A transceiver on a semiconductor chip may include as part of a transmitter circuit, a transmit DSP circuit that has the LUT, accumulator and device providing an n-bit signed constant to the accumulator to offset a transmit frequency in order to allow a receiver circuit on the transceiver to communicate directly with the transmitter circuit, and thus allowing testing of the transceiver.
    Type: Grant
    Filed: October 27, 2005
    Date of Patent: July 21, 2009
    Assignee: Cypress Semiconductor Corporation
    Inventors: Mark R. Gehring, Russell R. Moen, Brent R. Jensen
  • Publication number: 20090168857
    Abstract: A micro-controller to perform the FSK (HART) modem functions as well as communications and control functions in an isolated channel implementation is described. In one embodiment, the micro-controller comprises: a processor, an analog-to-digital converter configured to transform received analog signals into digital values at a predetermined digital sample rate; and a memory unit containing a set of computer-executable instructions that, when executed on the processor, provide a built-in FSK bi-directional modem function that converts the received digital values into binary signals. The FSK (HART) demodulation function is performed by the micro-controller with the built-in FSK modem function in three sequential phases implemented in computer code: (1) zero crossing and amplitude detection; (2) bit stream and timing generation, and (3) character generation and bit synchronization.
    Type: Application
    Filed: December 29, 2008
    Publication date: July 2, 2009
    Applicant: Spectrum Controls, Inc.
    Inventors: Carlos Golborne, Jay Tannenhaus
  • Publication number: 20090154597
    Abstract: A transmitter includes a dual mode modulator and an amplifier coupled to the dual mode modulator. The dual mode modulator implements a linear modulation scheme during a first mode of the modulator to produce a variable envelope modulated signal. The dual mode modulator implements a non-linear modulation scheme during a second mode of the modulator to produce a constant envelope modulated signal. The amplifier is biased as a linear amplifier during the first mode of the modulator and is biased as a non-linear amplifier during the second mode of the modulator. A feed-forward connection between the dual mode modulator and the amplifier is used to indicate a change in modulation mode and to adjust the bias of the amplifier. A power of the constant envelope modulated signal is increased such that an operating point of the amplifier remains substantially constant during the first and second modes of the modulator.
    Type: Application
    Filed: January 5, 2009
    Publication date: June 18, 2009
    Applicant: Broadcom Corporation
    Inventor: Meng-An PAN
  • Patent number: 7542520
    Abstract: A low complexity digital modulator, which is particularly useful for providing Gaussian frequency shift keying (GFSK) modulation, includes a filter, an integrator and a look-up table (LUT) stage. The filter is configured to receive a series of impulses and to generate a predetermined and fixed sequence of instantaneous frequency samples in response to each received impulse. The generated instantaneous frequency samples represent a predetermined type of filtering, such as Gaussian filtering, of the series of impulses. The integrator is configured to receive and integrate the instantaneous frequency samples to generate a sequence of phase samples. The LUT stage is configured to receive the phase samples and to generate sine and cosine samples of a complex baseband signal in response to each phase sample. The LUT stage stores only one quadrant of cosine samples and calculates the other cosine samples and all of the sine samples from the stored cosine samples.
    Type: Grant
    Filed: December 2, 1999
    Date of Patent: June 2, 2009
    Assignee: QUALCOMM Incorporated
    Inventor: Andrew Xavier Estrada
  • Patent number: 7495520
    Abstract: A frequency-shift modulation device includes an oscillating circuit, a phase-locked loop and a digital frequency modulation circuit. The oscillating circuit is connected to the phase-locked loop in order to produce a fixed-frequency clock signal. This clock signal is used for timing the frequency modulation circuit. A standard model crystal oscillator can be used in the oscillating circuit, given that the RF frequency of a wireless transmission signal which is produced by the modulation device is determined digitally.
    Type: Grant
    Filed: August 8, 2007
    Date of Patent: February 24, 2009
    Assignee: STMicroelectronics S.A.
    Inventor: Pascal Mellot
  • Patent number: 7474608
    Abstract: Methods and systems for communicating in a wireless network may distinguish different types of packet structures by modifying the phase of a modulation constellation, such as a binary phase shift keying (BPSK) constellation, in a signal field. Receiving devices may identify the type of packet structure associated with a transmission or whether the signal field is present by the phase of the modulation constellation used for mapping for the signal field. In one embodiment, the phase of the modulation constellation may be determined by examining the energy of the I and Q components after Fast Fourier Transform. Various specific embodiments and variations are also disclosed.
    Type: Grant
    Filed: December 20, 2004
    Date of Patent: January 6, 2009
    Assignee: Intel Corporation
    Inventors: Adrian P. Stephens, John S. Sadowsky
  • Patent number: 7474709
    Abstract: An FSK modulator and applications thereof are disclosed. The FSK modulator comprises a phase-locked loop, a frequency divider module, an image rejection mixer and a summing module. The phase-locked loop is operably coupled to generate a first oscillation from a reference oscillation. The frequency divider module is operably coupled to divide the first oscillation to produce a second oscillation. The image-rejection mixer is operably coupled to mix the second oscillation with a low intermediate oscillation to produce a mixed data signal, and the summing module is operably coupled to sum the mixed data signal with the first oscillation to produce an FSK modulated signal.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: January 6, 2009
    Assignee: Broadcom Corporation
    Inventors: Tom Baker, Henrik T. Jensen
  • Patent number: 7463698
    Abstract: A transmitter has a peak reducing part carrying out peak reduction processing; an OFDM signal generating part generating an OFDM signal from an input information signal; a cyclic shifting part generating a signal obtained from cyclically shifting the OFDM signal; and an adding part adding the OFDM signal and the cyclically shifted signal together.
    Type: Grant
    Filed: May 18, 2005
    Date of Patent: December 9, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hiromasa Fujii, Jiyun Shen, Takahiro Asai, Hirohito Suda
  • Patent number: 7447277
    Abstract: An OFDM receiver (1) is provided which includes a clock-frequency error calculation circuit (41) to calculate a difference in clock frequency between a clock for a received signal and an operation clock used in the receiver (1), and a guard correlation/peak detection circuit (12) to determine an autocorrelation of a guard interval and detect a peak timing of the correlation signal. The guard correlation/peak detection circuit (12) incorporates a free-running counter, and outputs a count of the free-running counter at the peak timing to the clock-frequency error calculation circuit (41). The clock-frequency error calculation circuit (41) uses a plurality of time-change rate detection circuits provided at different time intervals to calculate a time-change rate of an input count. The clock-frequency error calculation circuit (41) plots the time-change rates to generate a histogram and calculates a clock-frequency error from the histogram.
    Type: Grant
    Filed: December 18, 2003
    Date of Patent: November 4, 2008
    Assignee: Sony Corporation
    Inventors: Atsushi Yajima, Kazuhisa Funamoto, Yasunari Ikeda
  • Publication number: 20080253480
    Abstract: Method for modulating an RF signal includes the steps of modulating an RF signal using frequency shift keying (FSK) modulation to define a plurality of symbols (2030, 2031). The FSK modulation includes transitioning the modulated signal (204) between at least two different frequencies (f1 and f0) during a guard period (210). The method includes the further step of varying a frequency of the modulated signal 204 during the guard period (210) in accordance with a predetermined rate of change. The predetermined rate of change is selected to minimize a bandwidth of the RF signal.
    Type: Application
    Filed: April 12, 2007
    Publication date: October 16, 2008
    Applicant: HARRIS CORPORATION
    Inventors: William N. Furman, John W. Nieto
  • Patent number: 7424662
    Abstract: An approach is provided for a method of encoding structure Low Density Parity Check (LDPC) codes. Memory storing information representing a structured parity check Matrix of Low Density Parity Check (LDPC) codes is accessed during the encoding process. The information is organized in tabular form, wherein each row represents occurrences of one Values within a first column of a group of columns of the parity check matrix. The rows correspond to groups of columns of the parity check matrix, wherein subsequent columns within each of the groups are derived according to a predetermined operation. An LDPC coded signal is output based on the stored information representing the parity check matrix.
    Type: Grant
    Filed: December 8, 2006
    Date of Patent: September 9, 2008
    Assignee: The DIRECTV Group, Inc.
    Inventors: Mustafa Eroz, Feng-Wen Sun, Lin-Nan Lee
  • Publication number: 20080175336
    Abstract: Disclosed is a communication system, having: a transmitter including: a first frequency converter converting a frequency of a provided signal to a first frequency band to generate a first signal and converting the frequency of the provided signal to a second frequency band to generate a second signal, the second frequency band having a given frequency difference against the first frequency band; and a combiner combining the first signal and the second signal to output a transmission signal, and a receiver including: a second frequency converter converting the transmission signal to a frequency-shifting signal shifted by the given frequency difference; a first multiplier multiplying the transmission signal and the frequency-shifting signal together to output a multiplied signal; a filter extracting a baseband signal from the multiplied signal; and a detector detecting significant information from the baseband signal.
    Type: Application
    Filed: October 11, 2007
    Publication date: July 24, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Ren Sakata
  • Patent number: 7394869
    Abstract: The present invention provides a radio transmitter having a digital modulator that further includes logic for continuous amplitude and continuous phase modulation switching in an RF transmitter intended to support both frequency shift keying (FSK) and phase shift keying (PSK) modulation techniques in a smooth and continuous manner that does not violate spectral mask requirements. The invention supports continuous modulation switching both ways, i.e., from FSK to PSK and from PSK to FSK. In operation, the radio transmitter initially operates in a first communication mode, transmitting communication signals to a remote agent according to a first modulation technique at a first data rate and then transitions to the second modulation type at a second data rate without spectral mask violation.
    Type: Grant
    Filed: April 2, 2004
    Date of Patent: July 1, 2008
    Assignee: Broadcom Corporation
    Inventors: Henrik T. Jensen, Brima B. Ibrahim
  • Patent number: 7394862
    Abstract: A radio transmitter within a transceiver includes a digital processor and analog circuitry for modulating and transmitting an outgoing digital signal in multiple modes of operation. The digital processor digitally modulates the outgoing digital signal to produce one of a constant envelope modulated digital signal and a variable envelope modulated digital signal based on the particular modulation scheme being used to modulate the outgoing digital signal. In addition, the digital processor filters the outgoing digital signal using filter values selected based on the signal bandwidth of the outgoing digital signal. The analog circuitry converts digital envelope and phase signals of the modulated digital signal to analog envelope and phase signals, and up-converts the analog phase signal from an IF signal to an RF signal, using a loop filter that is programmable based on the signal bandwidth of the outgoing digital signal.
    Type: Grant
    Filed: December 21, 2004
    Date of Patent: July 1, 2008
    Assignee: Broadcom Corporation
    Inventors: Henrik T. Jensen, Ahmadreza (Reza) Rofougaran
  • Publication number: 20080152038
    Abstract: A data communication system includes a terminal identification information adding unit generating a unit carrier wave including a predetermined plurality of periods of carrier waves and arranging the unit carrier wave in arrangement patterns differing at every transmission terminal to generate a unit carrier row signal shorter than one bit of the digital transmission data, a transmission timing determination unit detecting a binary inversion timing of the digital transmission data and causing the terminal identification information adding unit to transmit the unit carrier row signal every time the binary is inverted, a reception timing distinguishing unit generating a reception timing signal in synchronization with reception of the unit carrier row signal and collecting the reception timing signal of the unit carrier row signal of the same type, and a digital data restoring unit inverting the binary according to the collected reception timing signal, restoring the digital transmission data.
    Type: Application
    Filed: April 16, 2007
    Publication date: June 26, 2008
    Applicant: PACIFIC INDUSTRIAL CO., LTD.
    Inventors: Shinichi Kawase, Youichi Okubo, Yasuhisa Tsujita, Syuji Aoyama
  • Patent number: 7376173
    Abstract: A method encodes a sequence of blocks of input bits to be transmitted over a wireless channel. Each block of input bits is converted to a codeword, and each codeword is mapped to multiple sub-blocks of complex numbers. Each sub-block is multiplied by a disambiguating spreading transform to obtain a sub-block of transformed symbols, which can be modulated and transmitted to a receiver, where each received block is demodulated to a block of complex numbers, which are partitioned into sub-blocks. The sub-block of complex numbers are converted to a set of likelihood ratios that correspond to decoded codewords. The input bits can be decoded unambiguously even if only one of the blocks of symbols corresponding to the block of input bits is received correctly.
    Type: Grant
    Filed: September 27, 2004
    Date of Patent: May 20, 2008
    Assignee: Mitsubishi Electric Research Laboratories, Inc.
    Inventors: Jonathan S. Yedidia, Andreas F. Molisch, Karunakar Pedagani
  • Patent number: 7369629
    Abstract: A demodulation circuit for demodulating an FSK signal comprising a long bit having a long bit period and a short bit having a short bit period comprises a bit boundary detection section for detecting a bit boundary timing of each bit, and a bit determination section for making determination for each bit such that a particular bit is determined to be a long bit when a threshold time period has passed during a period from a bit boundary timing at a leading end of the bit to a bit boundary timing at a trailing end of the bit, and a particular bit is determined to be a short bit when the threshold time period has not passed during a period from a bit boundary timing at a leading end of the bit to a bit boundary timing at a trailing end of the bit.
    Type: Grant
    Filed: September 2, 2004
    Date of Patent: May 6, 2008
    Assignee: Sanyo Electric Co., Ltd.
    Inventor: Masahiro Umewaka
  • Patent number: 7359456
    Abstract: A communication system for transmitting a transmission signal in digital form from a transmitter to a receiver is disclosed. The transmitter includes a modulation part modulating a carrier wave in accordance with the transmission signal according to frequency modulation, a digital conversion part performing 1-bit quantization on the modulated signal obtained as a result of the modulation in the modulation part, and a transmission part transmitting digital data into which the modulated signal is converted in the digital conversion part. The receiver includes a reception part receiving the digital data transmitted from the transmission part, and a demodulation part demodulating the digital data received by the reception part according to the frequency modulation.
    Type: Grant
    Filed: February 13, 2004
    Date of Patent: April 15, 2008
    Assignee: Mitsumi Electric Co., Ltd.
    Inventor: Toshikazu Ogino
  • Patent number: 7308043
    Abstract: A method of minimizing detectability of an electronically communicated message is disclosed. A predetermined frequency modulation pattern about a nominal transmission frequency is defined. The predetermined frequency modulation pattern is suitable to vary the nominal transmission frequency during a dwell period. The dwell period is divided into a plurality of sub-dwell periods. Each sub-dwell period has a nominal sub-frequency assigned thereto according to the predetermined frequency modulation pattern. The plurality of sub-dwell periods and the respective assigned nominal sub-frequencies are randomly or pseudo-randomly ordered. The message is transmitted according to the random or pseudo-random ordering of the nominal sub-frequencies.
    Type: Grant
    Filed: September 22, 2003
    Date of Patent: December 11, 2007
    Assignee: Rockwell Collins, Inc.
    Inventor: Robert J. Frank
  • Patent number: 7292645
    Abstract: The present invention provides a binary transmitter. In one embodiment, the binary transmitter includes a data coder that receives and encodes binary data to be transmitted and a modulator that employs the binary data directly to modulate a carrier wave to yield a stream of broadband RF signals. Also, the binary transmitter includes a header generator that interposes header information into the stream and an RF amplifier that amplifies the stream for transmission via an antenna. A method of transmitting data and a wireless data communication system incorporating the transmitter or the method are also disclosed.
    Type: Grant
    Filed: May 24, 2002
    Date of Patent: November 6, 2007
    Assignee: Agere Systems Inc.
    Inventor: Jan P. Kruys
  • Publication number: 20070211825
    Abstract: A Gaussian Frequency Shift Keying/Frequency Shift Keying (GFSK/FSK) modulation circuit implemented in a digital manner comprises a frequency divider for dividing frequency of an inputted clock signal to get a sampling signal, a buffer coupled to the frequency divider for storing inputted data, an integrator coupled to the buffer for processing integration according to the data outputted from the buffer, a first read only memory coupled to the integrator for transferring the data outputted from the integrator according to a cosine function, and a second read only memory coupled to the integrator for transferring the data outputted from the integrator according to a sine function.
    Type: Application
    Filed: November 28, 2006
    Publication date: September 13, 2007
    Inventors: Kwo-Wei Chang, Wen-Jan Lee
  • Patent number: 7269228
    Abstract: A non-coherent frequency shift keying transmitter for up-converting a baseband signal to a radio frequency signal is provided. The non-coherent frequency shift keying transmitter applies the interpolation method in a digital frequency synthesizer to replace the conventional Phase Locked Loop (PLL) circuit. The micro processing unit receives a baseband signal firstly, then the baseband signal is converted to a RF signal via a digital synthesizer, a numerical controlled oscillator, a cascaded integrator-comb filter, and a digital-analog converter. The RF signal is then transmitted via a local oscillator, a band-pass filter, a power amplifier, and a transmitting end. This circuit eliminates unnecessary analog devices so that fabrication migration issue is avoided. Further, the modulated RF signal is more stable than that of the conventional modulator, and has a more efficient spectrum control and a better performance on the receiver end.
    Type: Grant
    Filed: September 29, 2003
    Date of Patent: September 11, 2007
    Assignee: Novatek Microelectronics Corp.
    Inventor: David Shiung
  • Patent number: 7263137
    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: Grant
    Filed: April 30, 2003
    Date of Patent: August 28, 2007
    Assignee: Futaba Corporation
    Inventor: Michio Yamamoto
  • Patent number: 7249008
    Abstract: An arrangement for runtime compensation of a runtime difference, arising through emulation of a high frequency signal, is disclosed, with a signal x(t), for emulation by a signal processing device, which emulates the signal x(t) with a signal x(t) and a device for determining a difference signal between the signals x(t) and x(t). The arrangement is characterized in that the emulated signal x(t) is conducted via filter with a negative group runtime for certain frequency ranges.
    Type: Grant
    Filed: January 23, 2002
    Date of Patent: July 24, 2007
    Assignee: Nokia Siemens Networks GmbH & Co. KG
    Inventors: Björn Jelonnek, Armin Splett
  • Patent number: 7239625
    Abstract: A method for reducing the cost of demand control ventilation applications deploys wireless CO2 sensors inclusive of relative humidity and temperature throughout an indoor space without the need for wiring while utilizing the license-free 902-908 MHz ISM band by use of a Sequential Transmission Asynchronous Reception System (“STARS”) that is software controlled.
    Type: Grant
    Filed: May 11, 2004
    Date of Patent: July 3, 2007
    Inventors: Chi Wai Tse, Jacob Y. Wong
  • Publication number: 20070147544
    Abstract: An FSK signal modulator is provided in a transmitter which receives desired information to be transmitted on its input and which modulates the information to be transmitted to transmit a binary FSK signal. A counter counts a value of addition with the value of addition modified in accordance with a predetermined rule, depending on the value specified by the information to be transmitted, and for holding the counted value. The count value is determined by a threshold value decision circuit with respect to a threshold value. The result from the decision is output in the form of binary FSK signal. An FSK signal modulator will be provided which is simplified in circuit constitution.
    Type: Application
    Filed: December 1, 2006
    Publication date: June 28, 2007
    Inventor: Hiroji Akahori
  • Patent number: 7231190
    Abstract: A receiver front end (302) receives a known Stop Waveform (114) comprising a predetermined symbol pattern on a voice channel, the Stop Waveform sent at the end of a transmission. A processor (304) coupled to the receiver front end terminates (512) the reception of the voice channel in response to detecting the Stop Waveform. The processor computes (504) a plurality of characteristics derived from the received signal, including a carrier-to-noise ratio, a maximum normalized symbol correlation energy over all symbols of the Stop Waveform, and a number of small and a number of large normalized symbol energy values. The processor detects (506) the Stop Waveform by comparing the plurality of characteristics with a corresponding plurality of predetermined thresholds.
    Type: Grant
    Filed: July 28, 2003
    Date of Patent: June 12, 2007
    Assignee: Motorola, Inc.
    Inventor: Stephen R. Carsello
  • Patent number: 7200184
    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: Grant
    Filed: May 30, 2002
    Date of Patent: April 3, 2007
    Assignee: Motorola, Inc.
    Inventors: Gary Schulz, Chris Fay
  • Patent number: 7129802
    Abstract: The invention relates to a method of estimating a carrier leak making it possible to solve the accuracy degradation problem associated with a poor reception by the central carrier. A subject of said invention is a method of estimating a carrier leak consisting in: varying a complex gain Z applied to the received signal s between at least two predetermined values Z1 and Z2; measuring the position (PD1, PD2) of the central carrier of the signal s demodulated for each applied gain (Z1, Z2); calculating at least a part of the carrier leak based on the measured positions (PD1, PD2) and the applied gains (Z1, Z2), the calculated carrier leak part (offset_mod) corresponding to the leak due to the modulator.
    Type: Grant
    Filed: June 25, 2004
    Date of Patent: October 31, 2006
    Assignee: Thales
    Inventors: Julien Eyries, René Blaise
  • Patent number: 7123665
    Abstract: A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase preemphasis coefficients for compensating the frequency conversion gain of the apparatus, and the phase gain coefficient is used for stabilizing a frequency synthesis loop. The phase gain and preemphasis coefficients are determined in a calibration within the time constraints of on-line signal bursts based upon measured phase errors and accelerated predicted phase gain and preemphasis phase errors.
    Type: Grant
    Filed: May 9, 2003
    Date of Patent: October 17, 2006
    Assignee: Texas Instruments Incorporated
    Inventors: James E. C. Brown, Bret Rothenberg
  • Patent number: 7123666
    Abstract: A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase preemphasis coefficients for compensating the frequency conversion gain of the apparatus, and the phase gain coefficient is used for stabilizing a frequency synthesis loop. The phase gain and preemphasis coefficients are determined in a calibration within the time constraints of on-line signal bursts based upon measured phase errors and accelerated predicted phase gain and preemphasis phase errors.
    Type: Grant
    Filed: May 9, 2003
    Date of Patent: October 17, 2006
    Assignee: Texas Instruments Incorporated
    Inventors: James E. C. Brown, Bret Rothenberg, Chienkuo Vincent Tien
  • Patent number: 7103113
    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: Grant
    Filed: June 26, 2002
    Date of Patent: September 5, 2006
    Assignee: Broadcom Corporation
    Inventor: Hooman Darabi
  • Patent number: 7103108
    Abstract: A digital signal processor transceiver uses a finite impulse response filter memory to construct a phase integrated angle at each clock cycle. The FIR filter memory is addressed by a multibit pattern and a time count which are used in conjunction to determine the address. Each data word of the FIR filter memory represents the sum of two tap points multiplied by their tap coefficients. Several of the most significant bits of the phase integrated angle are used to address look up tables for the signal's sine and cosine values. The address for the cosine look up table may further be phase compensated. Filter types other than a FIR filter may be used.
    Type: Grant
    Filed: May 17, 2002
    Date of Patent: September 5, 2006
    Assignee: Cypress Semiconductor Corp.
    Inventor: Paul Beard
  • Patent number: 7076217
    Abstract: A radio transceiver comprises a reception path, a transmission path, and a frequency generator with a programmable phase lock loop. The reception path, the transmission path, and the frequency generator share a maximum amount of common circuitry to facilitate implementation of the entire radio transceiver on a single integrated circuit. The reception path includes an amplifier and a quadrature mixer for producing low intermediate frequency signals. The transmission path can be controlled by either a modulated voltage controlled transmitter or an in-phase and quadrature modulator transmitter.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: July 11, 2006
    Assignee: Micro Linear Corporation
    Inventors: Gwilym Francis Luff, Jerry Loraine
  • Patent number: 7058114
    Abstract: A high speed Bluetooth system with switch-to quadrature amplitude modulation allows for simple mobile devices with video data rates in applications such as Internet downloading. Mobile devices may have multiple antennas and adaptive hopping frequencies.
    Type: Grant
    Filed: February 26, 2001
    Date of Patent: June 6, 2006
    Assignee: Texas Instruments Incorporated
    Inventors: Anand G. Dabak, Timothy M. Schmidl, Mohammed Nafie
  • Patent number: 7027524
    Abstract: A method of transmitting QPSK digital signals in which each 2-digit binary number, referred to as a symbol, is assigned a phase of a carrier, and symbols are added to enable error correction at the receiver. The error correction code is a product code. To obtain transparency to phase rotations, the I bits (I1, I3, etc.) and the Q bits (Q2, Q4, etc.) of a symbol to be transmitted are placed in different rows but in the same column, so that each row contains only one type of bit, I or Q. The error correction coding is effected: row by row (NC-KC), and by pairs of adjacent columns, and the code I (or Q) bits of two associated adjacent columns are deduced from the I (or Q) bits of the two columns.
    Type: Grant
    Filed: January 14, 2002
    Date of Patent: April 11, 2006
    Assignee: Alcatel
    Inventor: Juing Fang
  • Patent number: 7026864
    Abstract: A non-coherent frequency shift key demodulator comprising an oversampling device, a chain of registers, and a threshold device is disclosed. The oversampling device receives an input digital non-coherent frequency shift signal, and examines for transitions therein, and thereby generating data bit signals in the form of logic high level ‘1’ or logic low level ‘0’ accordingly. The chain of registers receives, counts and stores the number of 1's data bit signals. Following, the threshold device compares the stored number of 1's in the chain of registers with a predetermined threshold value to extract the digital signal of the input digital non-coherent frequency shift signal. The non-coherent frequency shift key demodulator, by the use of a simple circuit and implementation, combats miscellaneous system impairments, such as frequency offset, and further support multi-rate transmission.
    Type: Grant
    Filed: February 11, 2004
    Date of Patent: April 11, 2006
    Assignee: Novatek Microelectronics Corp.
    Inventor: David Shiung
  • Patent number: 7016429
    Abstract: A method and apparatus are provided that generate, transmit, or receive a training sequence in a communications system, where the training sequence exhibits certain desirable characteristics when used by a peak to average power constrained modulation formal. In one embodiment, the invention includes selecting an original training sequence from a set of possible original training sequences having at least one desired property, forming a modified training sequence by modifying the original training sequence based on a corresponding modifying sequence, such that the modified training sequence exhibits the desired property of the original training sequence when used in a peak to average power constrained modulation format that would otherwise impair the desired property of the original training sequence.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: March 21, 2006
    Assignee: ArrayComm, LLC
    Inventors: Mithat C. Dogan, Mitchell D. Trott