Single Channel Patents (Class 331/39)
  • Patent number: 11262861
    Abstract: A display device includes a display including a plurality of pixels and an input sensor for sensing an input of a user. The display device includes: a driving controller for providing the display with a scan signal and a data signal according to a driving frequency; an input controller for providing a touch driving signal to the input sensor; a horizontal synchronization signal information line connecting the driving controller and the input controller, the horizontal synchronization signal information line transmitting a horizontal synchronization signal therethrough; and a vertical synchronization signal information line connecting the driving controller and the input controller, the vertical synchronization signal information line transmitting a vertical synchronization signal therethrough. Amplitude of the vertical synchronization signal or the horizontal synchronization signal varies according to the driving frequency.
    Type: Grant
    Filed: June 19, 2020
    Date of Patent: March 1, 2022
    Inventors: Sang Hun Park, Soo Won Kim, Il Ho Lee
  • Patent number: 9236846
    Abstract: An embodiment radio frequency MicroElectroMechanical (RF-MEMS) tunable bandpass filter includes one or more tunable resonators, each of which includes an electrically reconfigurable capacitor bank, a tuning screw, and a resonating structure. In an embodiment, the capacitor bank includes fixed value capacitors and switches to vary the capacitance of the resonator. In an embodiment, the capacitor bank includes variable capacitors and direct current (DC) bias circuits to vary the capacitance of the resonator. The filter may be incorporated into a time division duplexing (TDD) base station or other wireless communications device.
    Type: Grant
    Filed: February 21, 2012
    Date of Patent: January 12, 2016
    Assignee: Futurewei Technologies, Inc.
    Inventors: Siamak Fouladi Azarnaminy, Fengxi Huang, Dong Yan, Raafat Mansour
  • Patent number: 8116677
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: August 24, 2010
    Date of Patent: February 14, 2012
    Assignee: Broadcom Corporation
    Inventors: Ahmadreza Rofougaran, Maryam Rofougaran, Meng-An Pan, Hung-Ming Chien, Shahla Khorram, William T. Colleran, Jacob Rael, Masood Syed, Brima Ibrahim, Stephen Wu, Shervin Moloudi
  • Patent number: 7970358
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: May 18, 2010
    Date of Patent: June 28, 2011
    Assignee: Broadcom Corporation
    Inventors: Hooman Darabi, Ahmadreza Rofougaran, Maryam Rofougaran
  • Patent number: 7928808
    Abstract: A selectable local oscillator provides an output frequency signal having a selectable frequency within a desired output frequency range. The selectable local oscillator comprises first, second and third signal generators configured to provide first, second and third frequency signals having frequencies in first, second and third input frequency ranges. A first mixer provides a first mixed product signal having an upper sideband and a lower sideband. A frequency selector selects one of the upper and lower sidebands of the first mixed product signal. A second mixer provides a second mixed product signal having an upper sideband and a lower sideband. An output stage selects at least one of the upper and lower sidebands of the second mixed product signal as the output frequency signal.
    Type: Grant
    Filed: November 25, 2008
    Date of Patent: April 19, 2011
    Assignee: Raytheon Canada Limited
    Inventor: Tony Meng Yuen Chan
  • Patent number: 7809338
    Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. An input baseband signal is interpolated and upconverted in the digital domain to an IF. The LO operates at a frequency which is a n/m division of the target RF frequency fRF. The IF frequency is configured to ½ of the LO frequency. The upconverted IF signal is then converted to the analog domain via digital power amplifiers followed by voltage combiners. The output of the combiners is band pass filtered to extract the desired replica.
    Type: Grant
    Filed: August 24, 2007
    Date of Patent: October 5, 2010
    Assignee: Texas Instruments Incorporated
    Inventor: Yossi Tsfati
  • Patent number: 7805122
    Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The signal is input to a synthesizer timed to a rational multiplier of the RF frequency fRF. The signal is then divided to generate a plurality of phases of the divided signal. A plurality of combination signals are generated which are then multiplied by a set of weights and summed to cancel out some undersired products. The result is filtered to generate the LO output signal.
    Type: Grant
    Filed: August 24, 2007
    Date of Patent: September 28, 2010
    Assignee: Texas Instruments Incorporated
    Inventors: Gregory Lerner, Nir Tal
  • Patent number: 7783251
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: July 31, 2008
    Date of Patent: August 24, 2010
    Assignee: Broadcom Corporation
    Inventors: Ahmadreza Rofougaran, Maryam Rofougaran, Meng-An Pan, Hung-Ming Chien, Shahla Khorram, William T. Colleran, Jacob Rael, Masood Syed, Brima Ibrahim, Stephen Wu, Shervin Moloudi
  • Patent number: 7756472
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: June 17, 2008
    Date of Patent: July 13, 2010
    Assignee: Broadcom Corporation
    Inventors: Hooman Darabi, Ahmadreza Rofougaran, Shahla Khorram, Brima Ibrahim
  • Patent number: 7756487
    Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The input signal is fed to a synthesizer timed to a rational multiplier of the RF frequency L/N fRF. The clock signal generated is divided by a factor Q to form 2Q phases of the clock at a frequency of L(N*Q)fRF, wherein each phase undergoes division by L. The phase signals are input to a pulse generator which outputs a plurality of pulses. The pulses are input to a selector which selects which signal to output at any point in time. By controlling the selector, the output clock is generated as a TDM based signal. Any spurs are removed by an optional filter.
    Type: Grant
    Filed: August 24, 2007
    Date of Patent: July 13, 2010
    Assignee: Texas Instruments Incorporated
    Inventors: Gregory Lerner, Nir Tal, Robert B. Staszewski
  • Patent number: 7728684
    Abstract: Device and method for temperature compensation in a clock oscillator using quartz crystals, which integrates dual crystal oscillators. The minimal power consumption is achieved through an efficient use of a processor in charge of the synchronization of the two oscillators. The invention is particularly adapted for the provision of a precise reference clock in portable radiolocalization devices.
    Type: Grant
    Filed: September 10, 2007
    Date of Patent: June 1, 2010
    Assignee: QUALCOMM Incorporated
    Inventor: Andrew Tozer
  • Patent number: 7589597
    Abstract: A frequency synthesizer with a single PLL and multiple SSB mixers is presented. The frequency synthesizer includes a single PLL outputting a reference signal that is fed to a plurality of dividers coupled in sequence. The outputs from the dividers are mixed by the SSB mixers to produce signals with different frequencies. These signals with different frequencies can be selected through use of multiple selectors.
    Type: Grant
    Filed: October 5, 2007
    Date of Patent: September 15, 2009
    Assignee: VIA Technologies, Inc.
    Inventors: Ronald Chang, Sheng Yen, Wei Gao
  • Patent number: 7558556
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: October 27, 2000
    Date of Patent: July 7, 2009
    Assignee: Broadcom Corporation
    Inventors: Shervin Moloudi, Maryam Rofougaran
  • Patent number: 7512378
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: July 20, 2007
    Date of Patent: March 31, 2009
    Assignee: Broadcom Corporation
    Inventors: Ahmadreza Rofougaran, Maryam Rofougaran, Meng-An Pan, Hung-Ming Chien, Shahla Khorram, William T. Colleran, Jacob Rael, Masood Syed, Brima Ibrahim, Stephen Wu, Shervin Moloudi
  • Patent number: 7321268
    Abstract: A frequency synthesizer with a single PLL and multiple SSB mixers is presented. The frequency synthesizer includes a single PLL outputting a reference signal that is fed to a plurality of dividers coupled in sequence. The outputs from the dividers are mixed by the SSB mixers to produce signals with different frequencies. These signals with different frequencies can be selected through use of multiple selectors.
    Type: Grant
    Filed: March 16, 2006
    Date of Patent: January 22, 2008
    Assignee: VIA Technologies
    Inventors: Ronald Chang, Sheng Yen, Wei Gao
  • Patent number: 7299006
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: October 23, 2000
    Date of Patent: November 20, 2007
    Assignee: Broadcom Corporation
    Inventors: Ahmadreza Rofougaran, Maryam Rofougaran, Meng-An Pan, Hung-Ming Chien, Shahla Khorram, William T. Colleran, Jacob Rael, Masood Syed, Brima Ibrahim, Stephen Wu, Shervin Moloudi
  • Patent number: 7136622
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: April 19, 2005
    Date of Patent: November 14, 2006
    Assignee: Broadcom Corporation
    Inventors: Ahmadreza Rofougaran, Maryam Rofougaran, Hung-Ming Chien, Meng-An Pan
  • Patent number: 6975838
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: October 27, 2000
    Date of Patent: December 13, 2005
    Assignee: Broadcom Corporation
    Inventors: Ahmadreza Rofougaran, Maryam Rofougaran, Hung-Ming Chien, Meng-An Pan
  • Patent number: 6961546
    Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: October 27, 2000
    Date of Patent: November 1, 2005
    Assignee: Broadcom Corporation
    Inventors: Ahmadreza Rofougaran, Maryam Rofougaran, Jacob Rael, Syed Masood, Brima Ibrahim, Hung-Ming Chien, Stephen Wu, Meng-An Pan
  • 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: 5748047
    Abstract: A microwave frequency generator and method of generating a predetermined microwave signal. The invention comprises oscillator means to generate a determinable frequency signal and means responsive to the frequency signal received from the oscillator means to generate a predetermined Intermediate Frequency (IF) signal. The invention further includes means to generate a determinable ultrahigh frequency (UHF) signal, along with means responsive to the IF signal and to a UHF signal to generate a resultant frequency signal. Means responsive to the resultant frequency and to the predetermined frequency signal generated by the oscillator means are further provided to generate the desired predetermined microwave frequency signal.
    Type: Grant
    Filed: August 15, 1996
    Date of Patent: May 5, 1998
    Assignee: Northrop Grumman Corporation
    Inventors: Warren E. Guthrie, Gary S. Garbe
  • Patent number: 5598130
    Abstract: An FM signal generator generates an FM signal obtained by frequency-modulating a reference frequency signal with a modulating frequency signal. A first mixer mixes the FM signal and an input signal having a predetermined carrier frequency and outputs a pair of frequency signals having sum and difference frequencies thereof. A first signal extracting unit extracts one of the pair of frequency signals as an intermediate frequency signal. A delay circuit delays the extracted intermediate frequency signal by a predetermined time. A second mixer mixes the delayed intermediate frequency signal and the FM signal and outputs a pair of frequency signals having sum and difference frequencies. A second signal extracting unit extracts the frequency signal of the pair of frequency signals which corresponds to the carrier frequency component as a phase-modulated signal. The modulation degree and modulation frequency in phase modulation for the phase-modulated signal can be set in wide ranges.
    Type: Grant
    Filed: October 5, 1995
    Date of Patent: January 28, 1997
    Assignee: Anritsu Corporation
    Inventors: Etsuji Mesuda, Osamu Tagiri
  • Patent number: 5519359
    Abstract: A microwave oscillator with loop frequency conversion to and signal amplification at an intermediate frequency. A high-Q sapphire dielectric resonator is coupled in a frequency conversion loop between a pair of balanced mixers. One mixer comprises a downconversion mixer from an output frequency F.sub.0 to an intermediate frequency F.sub.IF, while the other mixer comprises an upconversion mixer from the intermediate frequency F.sub.IF to the output frequency F.sub.0. The frequency conversion loop additionally includes a low 1/f noise IF amplifier coupled between the mixers. The two mixers receive a local oscillator signal having a frequency F.sub.0 .+-.F.sub.IF from a microwave reference signal generator. In such an arrangement, an output frequency section and an intermediate frequency section is provided. The output frequency section includes the sapphire dielectric resonator and an output power divider while the intermediate frequency section includes the two mixers and the IF amplifier.
    Type: Grant
    Filed: April 26, 1995
    Date of Patent: May 21, 1996
    Assignee: Westinghouse Electric Corp.
    Inventor: Michael M. Driscoll
  • Patent number: 4916411
    Abstract: A circuit for generating jitter includes a mixer which mixes a jittered signal from a jitter generator with the output of a variable frequency oscillator to produce a broadband jittered output. A preferred form of the circuit uses a double frequency translation technique in which the output from a reference oscillator is applied to a jitter generator and to a first frequency translation device to translate a variable input frequency to an intermediate frequency. The jittered signal and the intermediate frequency signal are then applied to a second frequency translation device to produce a jittered output at the variable input frequency.
    Type: Grant
    Filed: May 19, 1989
    Date of Patent: April 10, 1990
    Assignee: Hewlett-Packard Company
    Inventor: Anthony Lymer
  • Patent number: 4626787
    Abstract: A frequency synthesizer is disclosed having n identical digital module stages, each of which stages generates one digit of the final frequency number of the synthesized frequency output signal. Each digit module stage comprises a series arrangement of a phase lock loop, a digit adder, and a digit shifter. The present invention provides a synthesized frequency generator with components that are inexpensive and readily available commercially, and moreover the frequency synthesizer is digitally controllable such that it is compatible with other digital control circuits.
    Type: Grant
    Filed: March 6, 1985
    Date of Patent: December 2, 1986
    Assignee: Harris Corporation
    Inventor: Joseph P. Mefford
  • Patent number: 4475090
    Abstract: A noise source is coupled through a first bandpass filter to a first mixer to which a first local oscillator signal is applied. The output of the first mixer is coupled through a second bandpass filter to a second mixer to which a second local oscillator signal is applied. At the output of the second mixer is obtained a noise signal having a bandwidth that can be varied by varying the frequency of the first local oscillator, and having a center frequency that can be varied by varying the frequency of the second local oscillator.
    Type: Grant
    Filed: August 23, 1982
    Date of Patent: October 2, 1984
    Assignee: Micronetics, Inc.
    Inventor: Kurt Stern
  • Patent number: 4425552
    Abstract: An apparatus including means for providing at least five fixed internal frequency signals having five different values of frequencies in which all of said frequencies are coupled into a first processor stage comprised of a single pole double throw switch controlled by a first input bit command signal for selecting either of two of said five frequencies for coupling into a first frequency mixer. A third frequency signal is also coupled into the first frequency mixer which provides a first difference frequency output signal that is coupled into a second frequency mixer. The second frequency mixer is coupled to a second single pole double throw switch controlled by a second input bit command signal for selecting either of the fourth or the fifth of said five frequencies. The difference output signal of the second frequency mixer is coupled to a frequency divider capable of division by four.
    Type: Grant
    Filed: August 17, 1981
    Date of Patent: January 10, 1984
    Assignee: Sperry Corporation
    Inventor: Ronald C. Stirling
  • Patent number: 4245193
    Abstract: An oscillation control circuit in which the output of an unstabilized oscillator is controlled using a bulk acoustic wave resonator. The circuit includes a high and low frequency loop with the power output of the oscillator being divided and supplied along respective paths to the high and low frequency portions of the loop. The high frequency portion of the loop, which includes the BAW resonator, operates at the output frequency f.sub.0, which is equal to the sum of the oscillator frequency f.sub.1 and the frequency f.sub.2 of the low frequency portion of the loop. A first mixer receives the frequencies f.sub.0 and f.sub.1 and produces an output f.sub.2 in the low frequency portion of the loop, while a second mixer receives the frequencies f.sub.1 and f.sub.2 and produces an output f.sub.0 in the high frequency portion of the loop. In this way, as the oscillator output frequency f.sub.1 varies, the frequency f.sub.
    Type: Grant
    Filed: August 9, 1978
    Date of Patent: January 13, 1981
    Assignee: Harris Corporation
    Inventors: Jing-Jong Pan, Milton P. Arnold
  • Patent number: 4100504
    Abstract: For eliminating an unwanted leaking local oscillator signal from the output of a double-balanced mixer circuit in a microwave frequency up-converter, a band rejection filter formed of series connected impedance inverter elements and a plurality of tuned cavity resonators is provided. The cavity resonators are integrally formed by the cylindrical walls of an aluminum housing, the top portion of which is formed of a plated printed circuit board. That face of the printed circuit board which faces the cylindrical cavities of the resonators is plated with copper to form the upper surface of each resonator. The other side of the printed circuit board is selectively plated with copper layers which extend through the board to the lower layer to provide an extensive ground plane.
    Type: Grant
    Filed: June 20, 1977
    Date of Patent: July 11, 1978
    Assignee: Harris Corporation
    Inventor: William E. McGann
  • Patent number: 3974457
    Abstract: The present invention relates to a time and frequency control unit which is apable of compensating for long-term crystal oscillator drift and other errors in a reference oscillator signal by both coarse and fine (vernier) controlling. The invention takes the reference oscillator frequency, f.sub.o, divides it by a controlled factor a and mixes f.sub.o with f.sub.o /a to produce an f.sub.o + f.sub.o /aSignal. The f.sub.o + f.sub.o /aSignal is then divided by a second controlled factor b and mixed again with f.sub.o to yield a signal of frequency f.sub.o .+-. (f.sub.o + f.sub.o /a) 1/b,Where f.sub.f, the final output frequency, is determined after a filter stage sets the operation sign of the above expression (to plus or minus). Where f.sub.f is intended to be constant with a changing f.sub.o, the values of a and b are changed. From the above expression, it is apparent that a change in a makes a fine correction whereas a change in b translates the frequency with a coarse adjustment.
    Type: Grant
    Filed: September 19, 1975
    Date of Patent: August 10, 1976
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Alvin G. Bates, Terrence L. McGovern