With Frequency Stabilization For At Least One Local Oscillator Patents (Class 455/316)
  • Patent number: 7058360
    Abstract: A method for stabilizing the performance variation of a primary radio frequency (RF) device is provided that includes providing a secondary RF device. An output signal is generated with the secondary RF device. The output signal is provided to a feedback circuit. A feedback signal is generated based on the output signal with the feedback circuit. The feedback signal is provided to the secondary RF device. The output signal is generated based on the feedback signal. The feedback signal is provided to the primary RF device.
    Type: Grant
    Filed: February 8, 2002
    Date of Patent: June 6, 2006
    Assignee: National Semiconductor Corporation
    Inventor: Daniel R. Meacham
  • Patent number: 7024170
    Abstract: A plurality of frequency conversion sections is provided, each of which comprises a first frequency mixer for converting the frequency of the input frequency signal by a signal from a first oscillator; a first filter for extracting an element signal from the output signal of the first frequency mixer; a second frequency mixer for converting the frequency of the output signal from the first filter by a signal from a second oscillator; and a second filter for extracting a element signal from the output signal of the second frequency mixer. The respective frequencies of the first and second oscillators are determined in accordance with a predetermined frequency setting rule specified by the relationship between the frequency conversion sections. The element signals sequentially arranged in a predetermined frequency interval can be rearranged in a desired frequency interval within a desired frequency bandwidth.
    Type: Grant
    Filed: November 7, 2002
    Date of Patent: April 4, 2006
    Assignee: Kabushiki Kaisha Kobe Seiko Sho
    Inventors: Chitaka Manabe, Yoshito Fukumoto
  • Patent number: 7013119
    Abstract: A radio communication apparatus includes a low-rate clock oscillator for generating a low-rate clock signal used for reception timing estimation; a frequency deviation measuring duration controller for determining a deviation measuring duration of measuring a frequency deviation of the low-rate clock signal in accordance with an intermittent time interval of the radio signal; a frequency deviation measuring section for measuring the frequency deviation of the low-rate clock signal over the deviation measuring duration; and a timing counter for correcting the frequency deviation of the low-rate clock signal, for measuring an intermittent span of the received signal in response to the low-rate clock signal after the correction, and for generating the estimated reception timing of the radio signal.
    Type: Grant
    Filed: June 3, 2002
    Date of Patent: March 14, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takahisa Yamauchi, Akihiro Shibuya
  • Patent number: 7003273
    Abstract: A temperature compensating circuit is provided in a radio unit, an ambient temperature is detected by a temperature sensor of the temperature compensating circuit, the detected temperature value is supplied to a correction address storage section as an address after it is converted to a digital value, and thus a correction address corresponding to a correct temperature value obtained by correcting the detected temperature value is read out. Then, the correction address is supplied to a frequency correction data storage section to read out frequency correction data corresponding to the corrected temperature value, and the frequency correction data is converted to an analog control voltage by a D/A converter and then supplied to a variable capacitance element of a reference oscillator, thereby making it possible to correct the reference oscillation frequency according to the temperature.
    Type: Grant
    Filed: June 21, 2000
    Date of Patent: February 21, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masanobu Shimanuki, Taku Hatsukano
  • Patent number: 6985708
    Abstract: A linearized oscillation synthesizer includes a phase and frequency detection module, charge pump circuit, low pass filter, voltage control oscillator, and a feedback module. The phase and frequency detection module is operably coupled to produce a charge-up signal, a charge-down signal, and an off signal based on phase and/or frequency differences between a reference oscillation and a feedback oscillation. The reference oscillation is generated by a clock source such as a crystal oscillator while the divider module generates the feedback oscillation by dividing the output oscillation by a divider value. The charge pump circuit produces a positive current in response to the charge-up signal, a negative current in response to the charge-down signal and also produces a non-zero offset current. The non-zero offset current shifts the steady state operating condition, and other operating conditions, of the charge pump into a linear region of charge pump performance curve.
    Type: Grant
    Filed: June 12, 2002
    Date of Patent: January 10, 2006
    Assignee: Broadcom, Corp.
    Inventors: Tsung-Hsien Lin, Hung-Ming Chien
  • Patent number: 6947499
    Abstract: An FM modulation signal is mixed with a pair of first local oscillation signals to be converted to a pair of base band signals. The base band signals are respectively mixed a pair of second local oscillation signals. The resultant signals are added together, thereby yielding an IF signal which is in turn detected. The local oscillator generates a reference oscillation signal whose frequency corresponds to a carrier component of the IF signal and frequency-divides the reference oscillation signal, thus generating the second local oscillation signals. The frequency of the first local oscillation signal converges to the one that has a given ratio to the frequency of the reference oscillation signal.
    Type: Grant
    Filed: March 28, 2001
    Date of Patent: September 20, 2005
    Assignee: Icom Incorporated
    Inventor: Kiyoshi Sakurai
  • Patent number: 6900700
    Abstract: A communication semiconductor integrated circuit has an oscillator circuit forming part of a transmission PLL circuit fabricated on a single semiconductor chip together with an oscillator circuit forming part of a reception PLL circuit and an oscillator circuit for an intermediate frequency. The oscillator circuit forming part of the transmission PLL circuit is configured to be operable in a plurality of bands. A circuit for measuring the oscillating frequency of the oscillator circuit forming part of the transmission PLL circuit is also used for measuring the oscillating frequency of the oscillator circuit forming part of the reception PLL circuit or for measuring the oscillating frequency of the oscillator circuit for the intermediate frequency.
    Type: Grant
    Filed: February 26, 2003
    Date of Patent: May 31, 2005
    Assignees: Renesas Technology Corp., TTPCOM Limited
    Inventors: Hirotaka Oosawa, Jiro Shinbo, Noriyuki Kurakami, Masumi Kasahara, Robert Astle Henshaw
  • Patent number: 6876844
    Abstract: A radio frequency (RF) demodulation circuit comprising: 1) a radio frequency (RF) mixer having a first input port capable of receiving an incoming RF signal having a frequency of RF and a second input port capable of receiving a first local oscillator (LO) signal having a frequency of LO, wherein the RF mixer generates a first intermediate frequency (IF) signal having a frequency of IF; 2) a frequency divider circuit capable of receiving the first LO signal having the frequency of LO and generating therefrom a second local oscillator (LO) signal having a frequency of LO/N and synchronized with the first LO signal; and 3) an intermediate frequency (IF) mixer having a first input port capable of receiving the first IF signal and a second input port capable of receiving the second LO signal having the frequency of LO/N, and wherein the IF mixer generates a baseband output signal.
    Type: Grant
    Filed: June 29, 2001
    Date of Patent: April 5, 2005
    Assignee: National Semiconductor Corporation
    Inventor: Hee Wong
  • Patent number: 6868135
    Abstract: A method and apparatus for correcting for a phase shift between a transmitter and receiver comprising the steps of: a) transmitting a signal from a transmitter (14); b) receiving the transmitted signal (16) at a receiver (20); c) comparing the received signal (17) to a reference signal; d) if a difference between the reference signal and the received signal (17) is greater than a predetermined value go to step e), if not go to step g); e) adjusting a frequency of the transmitted signal (16); f) go to step a); and g) calibration complete.
    Type: Grant
    Filed: May 18, 2000
    Date of Patent: March 15, 2005
    Assignees: Eastman Kodak Company, Rochester Institute of Technology
    Inventors: Daniel P. Phinney, Albert H. Titus
  • Patent number: 6847811
    Abstract: A circuit configuration having a filter, for example a bandpass filter, and a method for its operation are specified, which the circuit configuration allows for compensation of a frequency error, for example between an actual mid-frequency and a nominal frequency. A first mixer, upstream of the filter and a second mixer downstream from the filter are provided. A signal and a respective oscillation frequency are each supplied to respective inputs of the first and second mixers. The oscillation frequencies are mixed as a function of the frequency error in frequency generators such that the signal at the intermediate frequency is matched to the filter characteristics of the filter which is subject to tolerances. In consequence, filters that satisfy the stringent requirements for WCDMA mobile radio applications, but by virtue of the manufacturing technique, have an excessive mid-frequency error, can be used, for example, in heterodyne receivers.
    Type: Grant
    Filed: March 22, 2001
    Date of Patent: January 25, 2005
    Assignee: Infineon Technologies AG
    Inventor: Andreas Hofmann
  • Patent number: 6847812
    Abstract: A transceiver configuration has an integrated circuit (IC) with an A/D and/or D/A converter, a VCO with a reference oscillator, which provides a sampling clock for the A/D and/or D/A converter, and a digital data processing circuit. The IC is connected to a radio-frequency section, the frequency converter stage of which is operated with a beat frequency derived from the controllable oscillator frequency foz. A capacitive resonant element of the reference oscillator is disposed outside of the IC.
    Type: Grant
    Filed: April 23, 2001
    Date of Patent: January 25, 2005
    Assignee: Infineon Technologies AG
    Inventors: Markus Doetsch, Peter Jung, Jörg Plechinger, Peter Schmidt
  • Patent number: 6839551
    Abstract: There is disclosed a radio frequency (RF) demodulation circuit comprising: 1) a first RF mixer having a first input port for receiving an in-phase RF signal having a frequency of RF and a second input port for receiving an in-phase local oscillator (LO) signal having a frequency of LO, wherein LO is approximately equal to one-half of RF, and wherein the first RF mixer generates a first intermediate frequency (IF) signal having a frequency of LO; 2) a second RF mixer having a first input port for receiving an out-of-phase RF signal having a frequency of RF and a second input port for receiving an out-of-phase local oscillator (LO) signal having a frequency of LO, and wherein the second RF mixer generates a second intermediate frequency (IF) signal having a frequency of LO; and 3) a first signal combiner for combining the first and second IF signals to generate a composite IF signal, wherein the first signal combiner combines a first leakage signal from the first RF mixer and a second leakage signal from the se
    Type: Grant
    Filed: May 21, 2001
    Date of Patent: January 4, 2005
    Assignee: National Semiconductor Corporation
    Inventor: Hee Wong
  • Patent number: 6766157
    Abstract: An LO leakage canceller for a direct conversion receiver is disclosed. The canceller includes an RF input stage operating to provide at least two input signals, a local oscillator, an in-phase processor, and a quadrature processor. The local oscillator is configured to produce at least two reference signals for modulating the two input signals. Each of the in-phase and quadrature processors includes two consecutive quadrature splitters operating to substantially reduce leakage of the reference signal from the local oscillator to the RF input stage.
    Type: Grant
    Filed: January 3, 2001
    Date of Patent: July 20, 2004
    Assignee: Kyocera Wireless Corp.
    Inventors: Darin Hunzeker, Ralph Kaufman
  • Patent number: 6745020
    Abstract: A direct downconversion receiver combines a received RF signal and a local oscillator (LO) signal to form a combined signal. The local oscillator signal is also phase-shifted by approximately 90 degrees to form a quadrature signal. A mixer forms the product of the combined signal and the quadrature signal to produce a baseband output signal.
    Type: Grant
    Filed: August 29, 2002
    Date of Patent: June 1, 2004
    Inventors: Eugene Rzyski, Todd Wangsness
  • Publication number: 20040102176
    Abstract: The invention provides a semiconductor integrated circuit device having therein an oscillation circuit using either an oscillator or an oscillation module, which can be freely selected by the user, as an external part of a reference oscillation circuit without increasing the number of external parts and the number of external terminals. Two external terminals are provided in correspondence with an oscillation circuit. A control terminal (base terminal) of a transistor as a component of the oscillation circuit is connected to the one external terminal as one of the external terminals, and a path for feeding back a part of an output of the transistor to the control terminal is provided so that the oscillation circuit can oscillate. The other external terminal is connected to a power source voltage terminal via a resistive element of a high resistance value. Capacitor elements are connected between the two external terminals.
    Type: Application
    Filed: October 23, 2003
    Publication date: May 27, 2004
    Inventors: Norio Hayashi, Jiro Shinbo
  • Patent number: 6714263
    Abstract: A multiple conversion tuner comprises a plurality of cascade-connected frequency changers, each of which comprises a mixer and a local oscillator. The tuner also comprises a local oscillator frequency selecting circuit which controls the frequencies of the local oscillators. The frequencies are controlled so that the final mixer converts a desired signal to the final intermediate frequency and so that the frequency band occupied by the desired signal at the output of each mixer is within the passband of the following intermediate frequency part of the tuner.
    Type: Grant
    Filed: August 22, 2001
    Date of Patent: March 30, 2004
    Assignee: Zarlink Semiconductor Limited
    Inventor: Nicholas Paul Cowley
  • Publication number: 20040053595
    Abstract: A communication semiconductor integrated circuit has an oscillator circuit forming part of a transmission PLL circuit fabricated on a single semiconductor chip together with an oscillator circuit forming part of a reception PLL circuit and an oscillator circuit for an intermediate frequency. The oscillator circuit for the transmission PLL circuit is configured to be operable in a plurality of bands. The communication semiconductor integrated circuit also comprises a circuit for measuring the oscillating frequency of the oscillator circuit for the transmission PLL circuit, and a storage circuit for storing the result of measurement made by the measuring circuit. A band to be used by the oscillator circuit for the transmission PLL circuit is determined based on values for setting the oscillating frequencies of the oscillator circuit forming part of the reception PLL circuit and the intermediate frequency oscillator circuit, and the result of measurement stored in the storage circuit.
    Type: Application
    Filed: February 26, 2003
    Publication date: March 18, 2004
    Inventors: Jiro Shinbo, Hirotaka Oosawa, Noriyuki Kurakami, Masumi Kasahara, Robert Astle Henshaw
  • Patent number: 6650375
    Abstract: The frequency converters have first mixers for frequency converting input intermediate frequency band television signals into first intermediate frequency band television signals, first local oscillators for inputting the first local oscillation signals into the first mixers, second mixers for frequency converting the first intermediate frequency band television signals into the broadcasting channel television signals, and second local oscillators for inputting second local oscillation signals into the second mixers, wherein the frequency of the first local oscillation signals in the first frequency converter and the frequency of the first local oscillation signals in the second frequency converter are different from each other by 0.25 MHz or more.
    Type: Grant
    Filed: October 11, 2000
    Date of Patent: November 18, 2003
    Assignee: Alps Electric Co., Ltd.
    Inventor: Kazuyuki Maeda
  • Patent number: 6642797
    Abstract: An improved automatic frequency compensation (AFC) technique and apparatus is provided for piconet applications, e.g., BLUETOOTH™ applications. In particular, the present invention provides an offset normalizer which normalizes frequency offset against maximum deviations. By normalizing the frequency offset, before determination of an adjustment of a local oscillator, the local oscillator adjustment becomes uncorrelated with respect to gain along the receiving path (including in a demodulator). Thus, extremely precise adjustments can be made to the local oscillator in a piconet device to provide extremely precise automatic frequency compensation.
    Type: Grant
    Filed: April 25, 2002
    Date of Patent: November 4, 2003
    Assignee: Agere Systems, Inc.
    Inventors: Wenzhe Luo, Zhigang Ma
  • Patent number: 6580330
    Abstract: An apparatus for centering the frequency of an injection locked oscillator (ILO) measures the difference of the phase (or a parameter related to the phase) between ILO output signals in response to alternate high level and low level RF drive signals, and can tune the center frequency of the ILO in accordance with the measurements to minimize the phase difference.
    Type: Grant
    Filed: September 19, 2000
    Date of Patent: June 17, 2003
    Assignee: Broadband Innovations, Inc.
    Inventors: Ron D. Katznelson, Branislav A. Petrovic
  • Patent number: 6574462
    Abstract: A local oscillator apparatus is disclosed for use in radio frequency communication systems. The local oscillator apparatus comprises at least one mixer coupled to an oscillator input signal and to a feedback signal such that a local oscillator signal may be produced by fractional multiplication of the oscillator input signal. In an embodiment of the invention, the local oscillator apparatus includes a regenerative modulator comprising a pair of frequency dividers and a single side band mixer.
    Type: Grant
    Filed: August 25, 1999
    Date of Patent: June 3, 2003
    Assignee: Analog Devices, Inc.
    Inventor: Jonathan R. Strange
  • Patent number: 6560450
    Abstract: A satellite packet communications system comprises a number of ground-based sectors serviced via satellite communications nodes in polar orbits. Each sector is provided with an address incorporating a binary Gray code. Routing of a packet arriving at a satellite node and addressed to a particular sector is determined from the Grey code in the packet header. A comparison is performed between the packet address and an address stored in the node, the number and bit position of the difference between the nodes being used to determine the direction in which that packet should be routed.
    Type: Grant
    Filed: August 5, 1999
    Date of Patent: May 6, 2003
    Assignee: Nortel Networks Limited
    Inventors: Catherine Rosenberg, Juan C. Zuniga
  • Patent number: 6549588
    Abstract: Angle-modulated signals are transmitted in a communications system, in which coding information has been inserted into the transmitted data at regular intervals. The coding information is phase-modulated together with the transmitted data. This coding is used for pulse shaping, so that the receiver can recover the digital transmitted data with less implementation complexity and without carrier phase control by using appropriate signal processing.
    Type: Grant
    Filed: March 8, 2002
    Date of Patent: April 15, 2003
    Assignee: Infineon Technologies AG
    Inventor: Andre Neubauer
  • Publication number: 20030054786
    Abstract: An apparatus and a method compare the output signal of a mixer in a detector with one of two input signals of the mixer, in order to compensate for the offset of a mixer or modulator. The detector determines the sign of the offset of the mixer. A compensation value is formed in an actuator unit by successive approximation. The value is transmitted to the mixer. In an advantageous embodiment of the invention, a simple phase detector (PD) is used to determine the offset sign (VZ). The above-described indirect measuring method functions with very high accuracy, even at only a very small offset. Offsets in the circuits preceding the mixer (MI1) are compensated for simultaneously. A manual or individual calibration of direct voltage offsets is therefore unnecessary.
    Type: Application
    Filed: September 13, 2002
    Publication date: March 20, 2003
    Inventor: Michael Asam
  • Publication number: 20020168953
    Abstract: A frequency scanning receiver comprises a first local oscillator, a second local oscillator, a Nth local oscillator, a memory, a control circuit and etc.
    Type: Application
    Filed: May 6, 2002
    Publication date: November 14, 2002
    Inventors: Sadanori Shitara, Kiyoshi Wakui, Nobuaki Yokoyama
  • Publication number: 20020151292
    Abstract: A receiver (22) includes an IF filter (44) and a nearby process-variant circuit (80) formed on a common semiconductor substrate (24). The actual center frequency of the IF filter (44) is determined by resistors (70, 74) and capacitors (72, 76) exhibiting imprecise values and is unlikely to equal a nominal center frequency. The process-variant circuit (80) includes a test resistor (102) and test capacitor (104) formed using the same resistor-forming and capacitor-forming processes used to form the IF filter resistors (70, 74) and capacitors (72, 76). In response a test signal (88) from the process-variant circuit (80) and a reference signal (84) from a process-invariant circuit (82), a tuning parameter for a tunable local oscillator (90) is determined so that a local oscillation signal (94) will exhibit a frequency which, when mixed with an RF signal (38) yields an IF signal (42) at the actual center frequency of the IF filter (44).
    Type: Application
    Filed: April 11, 2001
    Publication date: October 17, 2002
    Inventors: Kazim Sevens, Majid M. Hashemi, Ismail H. Ozguc
  • Patent number: 6345177
    Abstract: An analog circuit for receiving satellite signals through an antenna. The circuit includes frequency transposition circuits and an analog/digital converter. Each frequency transposition circuit includes at least two frequency dividers of which due first is programmable so as to provide division ratios 140 and 143. The other divider provides one of the division ratios of 10 or 11. A third divider provides ratios of 3, 5, 7 or 8. These division ratios enable a single analog integrated circuit topography to allow a large number of possible applications including civil or military receivers operating on the GPS constellation or on the GLONASS constellation.
    Type: Grant
    Filed: August 2, 1999
    Date of Patent: February 5, 2002
    Assignee: Sextant Avionique
    Inventors: Alain Renard, Nelly Suaud
  • Publication number: 20020013131
    Abstract: A circuit configuration has a radio-frequency section with a receiving mixing stage, and has a signal processing circuit with an A/D converter, a digital filter and a frequency estimator. The frequency estimator continuously determines a first frequency correction control signal, which is representative of a frequency offset between the frequency of an IF received signal and a frequency which is characteristic of a pass band of the filter. The first frequency correction control signal is used for readjustment of the mixing frequency.
    Type: Application
    Filed: May 24, 2001
    Publication date: January 31, 2002
    Inventors: Markus Doetsch, Peter Jung, Jorg Plechinger, Peter Schmidt
  • Publication number: 20010014596
    Abstract: To obtain a radio set in a direct conversion system so as not to have any undesired influence of a signal of a transmission system on a reception system. In a transmission system, a frequency Flo of a local signal used in a frequency converting process performed by a frequency converter is expressed as (M/N)·Frx by a frequency conversion circuit. Based on the frequency Flo and the transmission frequency Ftx, a intermediate frequency Ftxif of the transmission system is expressed as Ftxif=Flo−Ftx=(M/N)·Frx−Ftx which is an oscillation frequency of a second local oscillator. Therefore, an equation exists as Ftx+Ftxif={(M/N)·Frx−Ftxif}+Ftxif=(M/N)·Frx, although Ftx+Ftxif leak to the reception system. As a result, since it is different from a reception frequency band, no interference wave is generated for a received signal.
    Type: Application
    Filed: February 13, 2001
    Publication date: August 16, 2001
    Inventors: Tetsuya Takaki, Masataka Mitama
  • Patent number: 6269241
    Abstract: This invention is a modular active filter that can be inserted between the antenna and a filter of a pre-existing unit, so that it can still function normally, without noise from cellular phones. This unit is modular. A heterodyning unit is used with a prefilter/amplifier unit and a post-filter/amplifier unit. After down converting the signal, while heterodyning, the signal is put through at least one crystal filter to filter out the noise introduced by cellular phones. To make sure that the unit works well with a wide variety of antenna-receiver pairs, the resonant frequency of the filters of the pre and post amplifier/filter units is set to the center frequency that the antenna and receiver are designed to handle. In this way, only one type of unit needs to be manufactured for each frequency band. An example of such an operating frequency might be 900 MHz. This invention has two types of embodiments. In one type embodiment the local oscillator produces only one fixed frequency.
    Type: Grant
    Filed: November 26, 1997
    Date of Patent: July 31, 2001
    Assignee: AeroComm, Inc.
    Inventor: Leon Masoian
  • Publication number: 20010008384
    Abstract: A method for generating frequencies in a dual phase locked loop (PLL). The method comprises the steps of: generating radio frequency local oscillations (RFLO) sequentially increased in the bandwidth at a given interval of more than two channels; and generating a group of intermediate frequency local oscillations (IFLO) gradually increased from a reference frequency channel by channel in said given interval, wherein said group of IFLOs are sequentially repeated at said given interval.
    Type: Application
    Filed: December 29, 2000
    Publication date: July 19, 2001
    Applicant: Samsung Electronics Co. Ltd.
    Inventor: Do-Il Ku
  • Patent number: 6181212
    Abstract: A method and apparatus for generating two disparate frequency reference signals using a single phase locked loop. The circuit includes a local oscillator for generating a reference signal and a phase comparator for comparing the reference signal with a feedback signal. The output of the phase comparator is converted to a first one of the desired output frequencies by a voltage controlled oscillator. That signal is also fed to a variable frequency divider circuit under control of a &Sgr;/&Dgr; converter which generates a lower frequency signal without creating a secondary frequency tone. The lower frequency signal is the second of the output frequencies. This signal also is fed back to the second input of the phase comparator through a fixed frequency divider.
    Type: Grant
    Filed: January 28, 1999
    Date of Patent: January 30, 2001
    Assignee: Lucent Technologies, Inc.
    Inventors: Ramin Khoini-Poorfard, Hussein K. Mecklai
  • Patent number: 6163687
    Abstract: A tuning module tunes a dual frequency PLL synthesized tuner to a desired channel frequency. The dual frequency PLL synthesized tuner includes a first PLL and a second PLL. The tuning module receives a carrier-to-noise ratio ("CNR") for each of one or more signals output from the dual frequency PLL synthesized tuner. The tuning module then generates first PLL parameters and second PLL parameters based on the CNRs and the desired channel frequency. Finally, the tuning module programs the first PLL with the first PLL parameters and programs the second PLL with the second PLL parameters.
    Type: Grant
    Filed: July 22, 1997
    Date of Patent: December 19, 2000
    Assignee: Intel Corporation
    Inventors: Stephen A. Scott, Nam Dang
  • Patent number: 6121847
    Abstract: A method for centering the frequency of an injection locked oscillator or (ILO) includes producing measurements of the magnitude and sign of the phase difference between ILO output signals in response to alternate high level and low level RF drive signals, and tuning the center frequency of the ILO in accordance with the measurements to minimize the phase difference.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: September 19, 2000
    Assignee: Broadband Innovations, Inc.
    Inventors: Ron D. Katznelson, Branislav A. Petrovic
  • Patent number: 6112069
    Abstract: A radio receiver, and a method therefore, for efficiently suppressing attenuation properties of a low frequency signal, in an analog frequency modulation type radio communication system. The radio receiver includes a first down-converter for mixing a modulated, high-frequency signal received by the radio receiver and a predetermined local oscillating signal to generate an intermediate frequency signal. A modulator modulates the predetermined local oscillating signal by an aural signal transmitted from the transmitter and generates a mixing signal for down-mixing the electrical signal representative of modulated, high-frequency signal. The mixed signal is then applied to the first down-converter. A second down-converter down-converts, in frequency, the intermediate frequency signal generated from the first down-converter into a baseband signal to generate the down-converted signal.
    Type: Grant
    Filed: January 15, 1998
    Date of Patent: August 29, 2000
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Bo-Gyu Na
  • Patent number: 6014546
    Abstract: A system and method is disclosed for distributing a radio frequency (RF) signal within a building structure or other structure not readily transparent to radio frequencies. The RF signal originates at a wireless local loop (WLL) base station and is intercepted by a main antenna on the building structure. The intercepted RF signal, which is contained in a RF bandwidth, is distributed throughout the building structure over a low bandwidth medium, e.g., in-building cabling, which has a transmission bandwidth below the RF bandwidth. In order to accomplish this, the system has a global reference oscillator for distributing a global reference tone of high stability to the entire system. Local oscillators controlled by this global reference tone deliver RF reference tones of high stability required for mixing the RF signal to obtain an intermediate frequency (IF) signal which is fed through the low bandwidth medium to remote sites.
    Type: Grant
    Filed: April 8, 1997
    Date of Patent: January 11, 2000
    Assignee: LGC Wireless, Inc.
    Inventors: John B. Georges, David M. Cutrer, Kam Y. Lau
  • Patent number: 6002924
    Abstract: A full-spectrum, multi-mode radio receiver provides truly continuous coverage of reception of radio signals in a variety of modes or formats, and in a frequency range extending from about 10 kHz to about 2600 MHz. That is, there or no frequencies or frequency bands within which reception is not possible or is possible only with a reduced performance of the radio receiver, because of spurs, inter-modulation products, or images. The radio receiver provides this broad-spectrum, continuous coverage of reception, and does so with a receiver front-end tuning selectivity to as little as 1 Hz.
    Type: Grant
    Filed: December 31, 1996
    Date of Patent: December 14, 1999
    Assignee: AOR, Ltd.
    Inventor: Shigeru Takano
  • Patent number: 5983070
    Abstract: A system and method for transmitting a radio frequency (RF) signal in a RF bandwidth over a low bandwidth medium, e.g., in-building unshielded twisted pair (UTP) cabling, which has a transmission bandwidth below the RF bandwidth. The system has a unit for receiving the RF signal and a global reference oscillator for distributing a global reference tone of high stability to the entire system. Local oscillators controlled by this global reference tone deliver RF reference tones of high stability required for mixing the RF signal to obtain an intermediate frequency (IF) signal which is fed through the low bandwidth medium to remote sites. A 10 base T cable network, often pre-existing in many building structures, provides a suitable, cost effective low bandwidth medium for such RF communication. Two of the four twisted pair cables of a UTP cable are sufficient to support bi-directional communication.
    Type: Grant
    Filed: April 8, 1997
    Date of Patent: November 9, 1999
    Assignee: LGC Wireless, Inc.
    Inventors: John B. Georges, David M. Cutrer, Kam Y. Lau
  • Patent number: 5974098
    Abstract: The present invention refers to a received signal detector for detecting and demodulating a digital modulated signal wherein a signal detection in a short time can be implemented independently of the signal frame length. The wide-band filter is a filter having a pass frequency band set to the frequency range of received signals to be demodulated. The A/D convertor, first power detector and first averaging circuit measure the average power of a signal having passed through the wide-band filter. The threshold setting circuit sets a threshold from the averaged power. The narrow-band filter filters an output signal of the frequency convertor in a narrower frequency band than the pass frequency band of the wide-band filter. The comparator circuit compares the threshold and the average power of a signal taken out from the second averaging circuit and passing through the narrow-band filter and judges whether the received signal is taken out from the wide-band filter.
    Type: Grant
    Filed: October 21, 1997
    Date of Patent: October 26, 1999
    Assignee: NEC Corporation
    Inventor: Hiroki Tsuda
  • Patent number: 5870669
    Abstract: A radio receiver which includes structure for direct-frequency-converting a received input signal to two axial base-band components including an in-phase base-band component and orthogonal phase base-band component. The radio receiver also includes structure for re-modulating the two axial base-band components of in-phase and orthogonal phase by using in-phase and orthogonal phase carrier waves where each carrier wave has a frequency equal to an IF signal frequency. Further, the radio receiver includes structure for composing the re-modulated components to provide the IF signal and for amplifying the IF signal, where the IF signal is an objective signal. The radio receiver further includes structure for detecting the objective signal to produce a detected output and for applying the detected output to a demodulated output terminal.
    Type: Grant
    Filed: July 2, 1996
    Date of Patent: February 9, 1999
    Assignee: General Research of Electronics, Inc.
    Inventor: Kazuo Kawai
  • Patent number: 5857004
    Abstract: A digital data receiver comprising a first frequency converter for converting a high frequency digital orthogonal modulation signal into a first intermediate frequency signal based on a first local oscillation signal, a second frequency converter for converting the first intermediate frequency signal into a second intermediate frequency signal based on a second local oscillation signal, and a demodulator for performing a orthogonal demodulation to the second intermediate frequency signal based on a third local oscillation signal, wherein the first local oscillation signal is generated by a variable oscillator for a PLL frequency synthesizer, the second local oscillation signal is generated by a high frequency oscillator in which its oscillation frequency is controlled based on the frequency control signal generated by the modulator to perform the orthogonal demodulation processing, and the third local oscillation signal is generated by a fixed oscillator in which its oscillation frequency is fixed.
    Type: Grant
    Filed: March 6, 1995
    Date of Patent: January 5, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Shuji Abe
  • Patent number: 5847612
    Abstract: An interference free local oscillator circuit is disclosed. A first local oscillator signal is generated in a first phase locked loop. A second local oscillator signal is generated in a second phase locked loop. Third and fourth phase locked loops provide inputs to the second phase locked loop to control the second local oscillator frequency. The operating frequencies of the first and second local oscillator signals are selected so that spurious signals generated in the phase locked loops do not interfere with a received RF signal in a conversion circuit.
    Type: Grant
    Filed: August 1, 1997
    Date of Patent: December 8, 1998
    Assignee: Microtune, Inc.
    Inventor: Vince Birleson
  • Patent number: 5774800
    Abstract: A radio communication apparatus includes a control section detecting the frequency of the intermediate-frequency signal from a mixer and adjusting the local oscillation frequency generated by a local oscillator on the basis of the detected intermediate frequency. The adjusted local oscillation frequency is supplied to the mixer to stabilize the intermediate frequency.
    Type: Grant
    Filed: March 1, 1996
    Date of Patent: June 30, 1998
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Kazuhiro Mori
  • Patent number: 5765099
    Abstract: A system and method for transmitting a radio frequency (RF) signal in a RF bandwidth over a low bandwidth medium, e.g., in-building cabling, which has a transmission bandwidth below the RF bandwidth. The system has a unit for receiving the RF signal and a global reference oscillator for distributing a global reference tone of high stability to the entire system. Local oscillators are controlled by adjustment signals derived from this global reference tone to deliver RF reference tones of high stability required for mixing the RF signal to obtain an intermediate frequency (IF) signal which is fed through the low bandwidth medium. The global reference tone is preferably delivered through the same low bandwidth medium to desired locations, such as remote coverage sites in a network for cellular communications, cordless telephony, local RF communications, interactive multi-media video, high bit-rate local communications.
    Type: Grant
    Filed: June 10, 1997
    Date of Patent: June 9, 1998
    Inventors: John B. Georges, David M. Cutrer, Kam Y. Lau
  • Patent number: 5752174
    Abstract: A radio selective calling receiver having at least two, i.e., a first and a second, local oscillators constituted by respective synthesizers. The oscillation frequencies of the local oscillator are controlled by the apparatus including a frequency calculator for executing frequency calculations according to the received call signal frequency and the oscillation frequencies of the first and second local oscillators so that harmonics of either one of the oscillation frequencies are not interference frequencies to the other oscillation frequency or the received signal frequency.
    Type: Grant
    Filed: July 29, 1994
    Date of Patent: May 12, 1998
    Assignee: NEC Corporation
    Inventors: Masahiro Matai, Kunitoshi Yonekura
  • Patent number: 5710997
    Abstract: A receiver apparatus comprises a first local oscillator, a first pair of mixer circuits, a second local oscillator, a second pair of mixer circuits, an adding circuit, a bandpass filter and a modulation circuit. When the frequency of a second local oscillating circuit varies, a center frequency of the bandpass filter also varies in the same way so as to eliminate tracking errors. A large portion of a circuit for a double superheterodyne receiver can thus be incorporated in a single IC chip, the receiver may be made simpler, and cheaper, and differences in the absolute values of the capacitors and resistors due to variation in manufacturing processes can be eliminated.
    Type: Grant
    Filed: January 24, 1996
    Date of Patent: January 20, 1998
    Assignee: Sony Corporation
    Inventor: Taiwa Okanobu
  • Patent number: 5697095
    Abstract: There is provided a tuner capable of improving reliability thereof with reduced power consumption and reduced heat generation. In the tuner, one wideband amplifier circuit including one transistor constitutes a buffer amplifier. The wideband amplifier circuit is coupled with a first local oscillator circuit in a DC coupling style. With the above-mentioned arrangement, the buffer amplifier is allowed to have a simplified circuit construction and reduce noises. Since the amplifier circuit and the local oscillator circuit are coupled with each other in a DC coupling style, reduced power consumption can be achieved.
    Type: Grant
    Filed: May 22, 1995
    Date of Patent: December 9, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Syuuji Matsuura
  • Patent number: 5697090
    Abstract: An SHF converter with less change in local oscillation frequency due to change in ambient temperature. The SHF converter is at least equipped with a low noise amplifier 1; a local oscillator circuit 5 with a dielectric resonator 13; a frequency converter 3; and a power-supply stabilizing IC, characterized in that a temperature sensing section 7 for sensing the temperature of the surroundings is placed near a metal cavity 12 housing the dielectric resonator 13, a first power-supply stabilizing IC 6a is placed at such a position as to accomplish efficient transfer of its generated heat to the metal cavity 12, while a second power-supply stabilizing IC 6b is placed at such a position that transfer of its generated heat to the metal cavity 12 is impeded, and a switch control section 8 and a selector switch 9 are also provided to switch activation between the first and the second power-supply stabilizing ICs 6a and 6b in a manner concordant with the temperature sensing section 7.
    Type: Grant
    Filed: March 18, 1996
    Date of Patent: December 9, 1997
    Assignee: NEC Corporation
    Inventor: Toshiyuki Iura
  • Patent number: 5696792
    Abstract: The number of oscillators required to construct a digital radiocommunication terminal can be reduced and a circuit used for the digital radiocommunication terminal can be reduced in size. For this purpose, the digital radiocommunication terminal for effecting information transmission using an N (integer)-phase-shift-keyed signal (identification symbol number N=4 upon .pi./4 shifted QPSK modulation), is constructed such that an oscillation frequency generated from a reference oscillator employed with a frequency synthesizer is selected to have a common multiple of a second intermediate frequency and an identification symbol phase N and is supplied to a detector for outputting received data therefrom.
    Type: Grant
    Filed: December 15, 1994
    Date of Patent: December 9, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Shigeyuki Sudo, Yasuaki Takahara, Katsumi Takeda, Jun Yamada
  • Patent number: 5691666
    Abstract: A FM (Frequency Modulated) DCFB (Deviation Compression Feedback) signal demodulator can be achieved by utilizing FM deviation compression feedback techniques. An FM signal is coupled to a mixer (10) wherein a signal from a local oscillator is mixed with the input signal. The output of the mixer is then coupled to a variable selective IF amplifier. The IF amplifier couples the signal to a limiter amplifier, the output of the limiter amplifier is FM demodulated and fed to an output. The output signal is simultaneously fed back through a variable Frequency Compensation Network (FCN) (Loop Filter). The output signal of the FCN is then fed back to a local oscillator (17). The output of the local oscillator (17) is in turn fed back into the original mixer (10). The improved demodulated signal is sampled at an output (26).
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: November 25, 1997
    Inventor: Joseph C. Owen