Frequency Patents (Class 360/30)
  • Patent number: 10643646
    Abstract: A magnetic tape apparatus includes a magnetic tape, a reading element unit and an extraction unit, in which the magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050, and an extraction unit performs a waveform equalization process according to a deviation amount between positions of the magnetic tape and the reading element unit, with respect to each reading result for each reading element, to extract data derived from the reading target track from the reading result.
    Type: Grant
    Filed: June 28, 2019
    Date of Patent: May 5, 2020
    Assignee: FUJIFILM Corporation
    Inventors: Norihito Kasada, Eiki Ozawa, Atsushi Musha
  • Patent number: 10629229
    Abstract: Disclosed herein are circuits, architectures, and methods that provide for the control of a data storage device write head's trailing shield and main pole potential with respect to the disk using circuitry that is integrated with circuitry used to bias a spin torque oscillator (STO) apparatus. Various embodiments include slider connections with STO bias circuitry that resides in a read/write integrated circuit, which has a programmable circuit that generates a bias current with overshoot (bias kicks). Also disclosed are circuits that may be incorporated into a slider to mitigate radio-frequency interference.
    Type: Grant
    Filed: August 11, 2019
    Date of Patent: April 21, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: John Contreras, Yunfei Ding, Kuok San Ho, Ian Robson McFadyen, Joey Martin Poss
  • Patent number: 9373355
    Abstract: The disclosure is related to systems and methods of compensating for interference via a multi-reader system. A transducer or read/write head may include a write element and multiple read elements. A compensation circuit can be configured to process read signals from the multiple read elements to reduce noise within the read signals, such as caused by the writer being simultaneously active or for other reasons. The read signals may be combined to produce a compensated read signal that has less noise than the original read signals.
    Type: Grant
    Filed: January 30, 2015
    Date of Patent: June 21, 2016
    Assignee: Seagate Technology LLC
    Inventors: Riyan Alex Mendonsa, Puskal P Pokharel, Timothy F Ellis
  • Patent number: 9030783
    Abstract: The embodiments disclosed generally relate to a read device in a magnetic recording head. The read device uses parametric excitation to injection lock the STO to an external AC signal with a frequency that is two times the resonance frequency, or more. The field from the media acting on the STO causes a change in the phase between the STO output and the external locking signal, which can be monitored using a phase detection circuit. The injection locking improves the STO signal to noise ratio and simplifies the detection circuit.
    Type: Grant
    Filed: February 6, 2014
    Date of Patent: May 12, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Patrick M. Braganca, Samir Y. Garzon, Bruce A. Gurney, Keyu Pi, Rehan A. Zakai, Jian Zhu
  • Publication number: 20150029608
    Abstract: A magnetic recording system includes an array of analog inputs operable to receive analog signals retrieved from a magnetic storage medium, a modulator operable to combine the analog signals to yield a frequency division multiplexed signal, a demodulator operable to yield a plurality of demodulated signals from the frequency division multiplexed signal corresponding to each channel of the array, and a joint equalizer operable to filter the plurality of demodulated signals to yield an equalized output.
    Type: Application
    Filed: September 9, 2013
    Publication date: January 29, 2015
    Applicant: LSI Corporation
    Inventors: George Mathew, Bruce Wilson, Suharli Tedja, Eui Seok Hwang
  • Patent number: 8654467
    Abstract: A disk drive is disclosed comprising a disk including a plurality of servo tracks defined by servo sectors, wherein each servo sector comprises a servo preamble. A head is actuated over the disk, wherein the head is operable to generate a read signal. The disk drive further comprises control circuitry including an analog cutoff filter operable to filter the read signal to generate a filtered read signal. The filtered read signal is sampled to generate read samples. During a normal operating mode, the analog cutoff filter is configured to have a first bandwidth. During a measurement mode, the analog cutoff filter is configured to have a second bandwidth greater than the first bandwidth, and the read samples representing at least part of the servo preamble are processed to measure a signal-to-noise ratio (SNR) and/or a fly height of the head.
    Type: Grant
    Filed: April 16, 2012
    Date of Patent: February 18, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Wai Ee Wong, Xiaotian Xu, Jinchuan Zheng, Guoxiao Guo, Jie Yu
  • Patent number: 8654465
    Abstract: A method, apparatus, and system are provided for implementing spin-torque oscillator (STO) sensing with a demodulator for hard disk drives. The demodulator measures an instantaneous phase of the readback signal from a STO sensor and converts the readback signal into a signal that is proportional to the magnetic field affecting the STO frequency during a bit time. The converted signal is used for processing by conventional data detection electronics.
    Type: Grant
    Filed: December 9, 2011
    Date of Patent: February 18, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Patrick Mesquita Braganca, Richard Leo Galbraith, Bruce Alvin Gurney, Neil Smith, Bruce Wilson, Rehan Ahmed Zakai
  • Patent number: 8570677
    Abstract: A method, apparatus, and system are provided for implementing spin-torque oscillator sensing with an enhanced integrated demodulator for hard disk drives. The demodulator receives an input signal from a STO read sensor having an oscillation frequency ? related to the strength of the detected magnetic signal field. The demodulator includes a pair of mixers coupled to a quadrature reference oscillator with respective quadrature components cos(?0t), and sin(?0t) of the quadrature reference oscillator being mixed with a received input signal to form signals at the sum and difference frequencies, ?±?0. Each of these mixer products is lowpass filtered by a respective a lowpass filter to remove the sum frequency components for providing a demodulator output signal that is directly proportional the STO oscillation frequency ?. The demodulator output signal is used for processing by data detection electronics.
    Type: Grant
    Filed: December 9, 2011
    Date of Patent: October 29, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Patrick Mesquita Braganca, Richard Leo Galbraith, Bruce Alvin Gurney, Neil Smith, Bruce Wilson, Rehan Ahmed Zakai
  • Patent number: 8553346
    Abstract: A method, apparatus, and system for implementing spin-torque oscillator (STO) sensing with an enhanced delay control feedback circuit for hard disk drives. A detector receives an input signal from a STO read sensor having an oscillation frequency related to the strength of the detected magnetic signal field. The received input signal is mixed with a time delayed input signal for providing a detector output signal. A low frequency component signal of the detector output signal is monitored and a delay control feedback is applied to an adjustable time delay to bias the DC signal of the detector output signal.
    Type: Grant
    Filed: December 9, 2011
    Date of Patent: October 8, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Patrick Mesquita Braganca, Richard Leo Galbraith, Bruce Alvin Gurney, Neil Smith, Bruce Wilson, Rehan Ahmed Zakai
  • Publication number: 20130148224
    Abstract: A method, apparatus, and system are provided for implementing spin-torque oscillator sensing with an enhanced integrated demodulator for hard disk drives. The demodulator receives an input signal from a STO read sensor having an oscillation frequency ? related to the strength of the detected magnetic signal field. The demodulator includes a pair of mixers coupled to a quadrature reference oscillator with respective quadrature components cos(?0t), and sin(?0t) of the quadrature reference oscillator being mixed with a received input signal to form signals at the sum and difference frequencies, ?±?0. Each of these mixer products is lowpass filtered by a respective a lowpass filter to remove the sum frequency components for providing a demodulator output signal that is directly proportional the STO oscillation frequency ?. The demodulator output signal is used for processing by data detection electronics.
    Type: Application
    Filed: December 9, 2011
    Publication date: June 13, 2013
    Applicant: Hitachi Global Storage Technologies Netherlands. B.V.
    Inventors: Patrick Mesquita Braganca, Richard Leo Galbraith, Bruce Alvin Gurney, Neil Smith, Bruce Wilson, Rehan Ahmed Zakai
  • Publication number: 20130148223
    Abstract: A method, apparatus, and system are provided for implementing spin-torque oscillator (STO) sensing with a demodulator for hard disk drives. The demodulator measures an instantaneous phase of the readback signal from a STO sensor and converts the readback signal into a signal that is proportional to the magnetic field affecting the STO frequency during a bit time. The converted signal is used for processing by conventional data detection electronics.
    Type: Application
    Filed: December 9, 2011
    Publication date: June 13, 2013
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Patrick Mesquita Braganca, Richard Leo Galbraith, Bruce Alvin Gurney, Neil Smith, Bruce Wilson, Rehan Ahmed Zakai
  • Patent number: 8144415
    Abstract: To effectively suppress a signal in a low frequency region in which the medium noise and the signal distortion are concentrated, and in order to effectively utilize a detected component of the reproduced signal in the low frequency region, a target of partial response equalization to the perpendicularly recorded/reproduced signal is set so that the low-frequency component around the direct current is suppressed to a regulated quantity for both the effective suppression and the effective utilization. Accordingly, a maximum-likelihood decoding process is carried out through the target of partial response equalization. Reliability of data detection is made higher and a signal-to-noise ratio is improved, so that the noise from the recording medium can be reduced more and it is possible to provide a high-density magnetic recording/reproducing apparatus.
    Type: Grant
    Filed: September 14, 2010
    Date of Patent: March 27, 2012
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Hideki Sawaguchi, Yasutaka Nishida, Hisashi Takano, Hiroyuki Tsuchinaga
  • Patent number: 8094401
    Abstract: A method of detecting skip track erasure for a head and disk of a disk drive is disclosed. N tracks are DC erased, and a periodic pattern is written to the disk at a target track within the DC erased tracks. The periodic pattern is substantially comprised of a high frequency component greater than 450 MHz. After writing the periodic pattern to the target track at least twice, at least two of the DC erased tracks other than the target track are read to generate respective read signals. The read signals are processed to detect a skip track erasure event.
    Type: Grant
    Filed: March 17, 2008
    Date of Patent: January 10, 2012
    Assignee: Western Digital Technologies, Inc.
    Inventors: Qingzhi Peng, Kathy X. Tang
  • Patent number: 7982986
    Abstract: A magnetic head, includes a magnetic oscillation element, the oscillation frequency of which is modulated by a medium magnetic field, and a reproducing device configured to detect a phase difference between the adjacent oscillation signals derived from the magnetic oscillation element and output a phase difference signal as a reproduced signal.
    Type: Grant
    Filed: September 24, 2010
    Date of Patent: July 19, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Rie Sato, Koichi Mizushima
  • Patent number: 7881821
    Abstract: A media storage system includes a disc input element for receiving a media disc, a disc output element for ejecting a disc, and a media reader for reading information from a disc. If insufficient information is readable from a disc, it may be obtained through a computer network. The system includes a disc transporter for moving received discs to respective internal storage locations. The system includes a data input device for entering disc catalogue data and a data output device such as a display for displaying disc catalogue data. The data input and output devices may be input buttons and a display on a remote control. Each disc and related information is associated with an identifier such that access to disc data may be by restricted by user identifier or content ratings.
    Type: Grant
    Filed: September 5, 2007
    Date of Patent: February 1, 2011
    Assignee: Shyam Consultants, LLC
    Inventors: Atul K. Kampani, Pranav A. Kampani
  • Publication number: 20110013304
    Abstract: A magnetic head, includes a magnetic oscillation element, the oscillation frequency of which is modulated by a medium magnetic field, and a reproducing device configured to detect a phase difference between the adjacent oscillation signals derived from the magnetic oscillation element and output a phase difference signal as a reproduced signal.
    Type: Application
    Filed: September 24, 2010
    Publication date: January 20, 2011
    Inventors: Rie Sato, Koichi Mizushima
  • Patent number: 7826160
    Abstract: A magnetic head, includes a magnetic oscillation element, the oscillation frequency of which is modulated by a medium magnetic field, and a reproducing device configured to detect a phase difference between the adjacent oscillation signals derived from the magnetic oscillation element and output a phase difference signal as a reproduced signal.
    Type: Grant
    Filed: September 19, 2008
    Date of Patent: November 2, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Rie Sato, Koichi Mizushima
  • Patent number: 7821731
    Abstract: A storage channel, e.g., for a disk drive system, may asynchronously sample and buffer an entire sector, and then process the buffered sector to recover timing information. The storage channel may operate in an open-loop and utilize an exhaustive search to determine timing parameters. Alternatively, the storage channel may operative in a closed-loop, processing the sector once, and feeding back information obtained during decoding to the timing loop.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: October 26, 2010
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Ke Han, Zining Wu
  • Publication number: 20100157454
    Abstract: In a method of head-disk contact detection in a hard disk drive, a Radio Frequency (RF) carrier signal is injected into a slider which is flying above a surface of a disk in a hard disk drive. A modulated version of the RF carrier signal is received from the slider. The modulated version of the RF carrier signal is demodulated to achieve a demodulated signal. A signal spectrum of a range of frequencies in the demodulated signal is monitored for activity indicative of a contact between a head of the slider and the surface of the disk. An occurrence of the contact is determined based upon an occurrence of the activity.
    Type: Application
    Filed: December 23, 2008
    Publication date: June 24, 2010
    Inventors: Martin Yu-Wen CHEN, John Contreras, Luiz M. Franca-Neto, Bernhard E. Knigge
  • Patent number: 7742250
    Abstract: The present disclosure is directed to spectral analysis of a position error signal. In a particular embodiment, the method includes analyzing a spectral content of a position error signal. The method also includes comparing the spectral content to a threshold. Further, the method includes determining a result based on the comparing the spectral content to the threshold. In another particular embodiment, the spectral content of the position error signal is determined by performing a discrete fourier transform (DFT) on the error signal, determining a magnitude of the DFT output, and low pass filtering the magnitude.
    Type: Grant
    Filed: January 12, 2007
    Date of Patent: June 22, 2010
    Assignee: Seagate Technology LLC
    Inventors: Jeff Nelson, Farhad Navid, Richard Martin, Anton Viktorovich Goldade
  • Patent number: 7667916
    Abstract: Apparatus, systems, and methods implementing techniques for converting a signal. In an apparatus form, an input circuit receives a differential input signal and produces a single-ended intermediate signal. An amplifier circuit receives the intermediate signal and produces an amplified signal, and a feedback path couples the amplified signal to the intermediate signal. An inverter circuit receives the amplified signal and produces an output signal.
    Type: Grant
    Filed: April 26, 2004
    Date of Patent: February 23, 2010
    Assignee: Marvell International Ltd.
    Inventor: Farbod Aram
  • Patent number: 7583457
    Abstract: A method includes loading an optical media image representing the content of a physical optical media device from an optical media image source into random access memory (RAM) and emulating the physical optical media device using the optical media image. The optical media image is in an optical media format. A system includes an optical media image stored in random access memory (RAM), the optical media image being in an optical media format, and including operating system (OS) code executable by a microprocessor. A RAM disk program accesses the optical media image according to the optical media format.
    Type: Grant
    Filed: March 22, 2004
    Date of Patent: September 1, 2009
    Assignee: Microsoft Corporation
    Inventors: Wesley Miller, Saad Syed, Charles T. Lenzmeier
  • Publication number: 20090086354
    Abstract: A magnetic head, includes a magnetic oscillation element, the oscillation frequency of which is modulated by a medium magnetic field, and a reproducing device configured to detect a phase difference between the adjacent oscillation signals derived from the magnetic oscillation element and output a phase difference signal as a reproduced signal.
    Type: Application
    Filed: September 19, 2008
    Publication date: April 2, 2009
    Inventors: RIE SATO, Koichi Mizushima
  • Patent number: 6943970
    Abstract: Position information PosN and PosQ are compared and position information Pos1 and Pos2 in which influences of an error of a position sensitivity gain appear oppositely are calculated. Subsequently, a weight gain G1=M and a weight gain G2=(1?M) are obtained from the position information Pos1. A multiplication value obtained by multiplying the third position information Pos1 by the weight gain G1 and a multiplication value obtained by multiplying the fourth position information Pos2 by the weight gain G2 are added and synthesized, thereby calculating a decoded position.
    Type: Grant
    Filed: January 11, 2002
    Date of Patent: September 13, 2005
    Assignee: Fujitsu Limited
    Inventors: Kazuhiko Takaishi, Takeyori Hara, Eiji Okamura
  • Patent number: 6930845
    Abstract: Method and apparatus for recording data on a magnetic recording medium and writing data to a computer bus in which the data is divided into words of a predetermined length, a signal is generated for each data word, having an amplitude which is representative of the value of the data word, and this signal is then recorded to the magnetic recording medium or written to the computer bus. Complementary method and apparatus is provided for reading the data from the magnetic recording medium and the computer bus.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: August 16, 2005
    Assignee: Trix SRT Limited
    Inventor: Phil Haylor
  • Patent number: 6853652
    Abstract: An optical servo writer system including a laser subsystem to generate a multiplicity of light beams, a lens positioned to receive and focus the light beams and a spatial filter positioned in the system so as to allow a subset of the light beams to pass through the filter. The multiplicity of light beams includes the subset that contains the desired beams, or the servo beams, and also the undesired beams, called the ghost beams. The system further includes a digital linear tape positioned adjacent the spatial filter with the spatial filter allowing the subset of light beams to hit the digital linear tape and produce servo marks. The spatial filter includes openings positioned to allow the subset of light beams to pass through the filter. The openings may be staggered relative to the digital linear tape to prevent debris generated by the marking process from clogging the openings.
    Type: Grant
    Filed: June 27, 2001
    Date of Patent: February 8, 2005
    Assignee: Quantum Corporation
    Inventors: Tzuo-Chang Lee, Arkady Feldman
  • Patent number: 6809585
    Abstract: A frequency modulation system is disclosed which includes a voltage-controlled oscillator (VCO) 43 and a phase detector 47 configured to receive an output signal from the VCO. The phase detector is arranged to output an error signal representing the phase difference between the signal from the VCO and a reference signal. The system also includes control means 62 arranged to monitor the error signal to derive an indication of the frequency deviation of the VCO, and, in accordance with this derivation, to maintain the frequency deviation of the VCO substantially constant.
    Type: Grant
    Filed: May 30, 2003
    Date of Patent: October 26, 2004
    Assignee: Zarlink Semiconductor Limited
    Inventor: Peter Edward Chadwick
  • Patent number: 6687452
    Abstract: A magnetic recording device provided with a frequency modulation circuit, a filter circuit, and a frequency conversion circuit. The frequency modulation circuit generates a modified FM luminance signal the frequency of a carrier wave of which is higher than that of an FM luminance signal and the relationship between the frequency of a sink chip and the frequency of a white peak of which is equal to the relationship between the frequency fs and the frequency fw of the FM luminance signal when the minimum frequency of the frequency band of the FM luminance signal is the frequency fa. The filter circuit removes a signal component lower than a cut-off frequency of signal components included in the modified FM luminance signal when a frequency. lower than the minimum frequency of the band of the modified FM luminance signal by a frequency acquired by doubling the frequency fa is the cut-off frequency.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: February 3, 2004
    Assignee: Funai Electric Co., Ltd.
    Inventor: Yoshio Higuchi
  • Patent number: 6678110
    Abstract: A robust and efficient method for determining the location of a transducer head in a mass storage system. A position-indicative signal characterized by a fundamental frequency F is received from a data path including the transducer head. Energy in the signal at frequencies smaller than F/10 is substantially attenuated by a special filter, which may be an analog or digital differentiator. A sequence of bits indicative of the transducer head position indicator is then extracted from the digitized, filtered signal.
    Type: Grant
    Filed: March 30, 2001
    Date of Patent: January 13, 2004
    Assignee: Seagate Technology LLC
    Inventor: Timothy Francis Ellis
  • Publication number: 20030184900
    Abstract: Method and apparatus for recording data on a magnetic recording medium and writing data to a computer bus in which the data is divided into words of a predetermined length, a signal is generated for each data word, having an amplitude which is representative of the value of the data word, and this signal is then recorded to the magnetic recording medium or written to the computer bus. Complementary method and apparatus is provided for reading the data from the magnetic recording medium and the computer bus.
    Type: Application
    Filed: April 11, 2003
    Publication date: October 2, 2003
    Inventor: Phil Haylor
  • Patent number: 6564290
    Abstract: In order to design a data storage unit, comprising an archive storage means for data carrier cassettes, with at least one read/write unit and a transfer unit, and further comprising a data storage control which controls the read/write unit and the transfer unit for storing data and which is in data interchange communication with a computer, with which access to data with the computer is as efficient as possible, it is suggested that the data storage unit have in addition to the archive storage means at least one hard disk memory, that the data storage control operate the hard disk memory and the archive storage means in parallel, that the data storage control with the archive storage means and the at least one hard disk memory together form a device installable as one storage unit which communicates with the computer as a single storage unit.
    Type: Grant
    Filed: July 28, 1998
    Date of Patent: May 13, 2003
    Assignee: Grau Software GmbH
    Inventor: Ulrich Lechner
  • Patent number: 6490109
    Abstract: There is provided a data storage device concurrently allowing storage of data that can be reproduced in higher quality and storage of data that can be used also in a data transmission path with a lower transfer speed. The data storage device comprises an A/D converter 103 for sampling analog audio signals based on a sampling frequency, a DSP 104 for compressing sample data sequentially output from the A/D converter 103, a storing and reading control unit 107 for storing the compressed data sequentially output from the DSP 104, and a control unit 105 for controlling the DSP 104 and the storing and reading control unit 107 for dividing the sample data sequentially output from the A/D converter 103 into a group under odd number of turns and a group under even number of turns, compressing the groups at each different compression rate and storing them on different storage areas A and B, respectively.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: December 3, 2002
    Assignee: Denon Ltd.
    Inventor: Shingo Ushirogi
  • Patent number: 6404584
    Abstract: A voice recorder including a housing having a general image display mounted therein, and further including a pressure-sensitive variable-conductance sensor for creating a varying analog value according to varying depression applied by a finger of a human user to the analog sensor. Multiple analog sensors are sometimes utilized. In one preferred embodiment the analog sensor(s) include resilient dome cap(s) for providing tactile feedback to the finger depressing the analog sensor. Circuitry within the housing is connected to the analog sensor for reading the varying analog value from the analog sensor and causing representative varying of the imagery shown by the display.
    Type: Grant
    Filed: December 8, 2000
    Date of Patent: June 11, 2002
    Inventor: Brad A. Armstrong
  • Patent number: 6392835
    Abstract: An object of the invention of the present application is to provide an information recording medium library apparatus in which the position of the drive with respect to the main body is fixed precisely, and has a simple structure, and a low cost; in order to achieve the object, the present invention provide an information recording medium library apparatus comprising a main body comprising a storage device for storing a plurality of information recording medium and a transferring device for transferring the information recording medium; and a sub body comprising a drive for reading and information recorded in the information recording medium and writing an information to the information recording medium and a tray for carrying the drive comprising: a sub body fixing device for positioning and fixing the sub body with respect to the main body, a drive positioning equipment for positioning precisely the drive in the tray, a drive fixing equipment for fixing the drive in the tray, abutting portions provided with
    Type: Grant
    Filed: March 15, 2000
    Date of Patent: May 21, 2002
    Assignee: NEC Corporation
    Inventor: Kiyoaki Egawa
  • Patent number: 6369966
    Abstract: In order to reproduce the audio signal which has been recorded as an FM audio signal in the slanted tracks of a recording medium in tape form by means of read/write heads arranged on a rotating head drum, it is possible to use PLL circuits which are designed as FM demodulators and in each case form a phase-locked loop with a VCO. FM demodulators of this type generally operate satisfactorily e.g. in video recorders with improved audio signal recording, but there is the risk of the frequency of the VCO of the respective FM demodulator drifting when the read/write head assigned to it leaves the wrap-around region of the recording medium on the head drum and only being able to be synchronized with the FM audio signal when the said head re-enters the recording medium.
    Type: Grant
    Filed: December 3, 1998
    Date of Patent: April 9, 2002
    Assignee: Deutsche Thomson-Brandt GmbH
    Inventor: Hans-Jürgen Kluth
  • Patent number: 6151076
    Abstract: A system for phase-locking a clock to a digital audio signal embedded within a digital video signal uses an audio extractor, frequency dividers, and an adjusted bandwidth loop filter to prevent phase jitter associated with the digital audio signal preventing the functionality of the phase-lock loop or having unacceptable effects on the generated audio sample frequency signal. Extracted audio samples are divided down and input to a phase detector. The signal is then filtered using a series of loop filters, one of which has an adjusted bandwidth to reject phase jitter. A clock then outputs the generated synthesized audio sample frequency using the output from the series of loop filters, and the synthesized frequency signal is looped back through a second frequency divider to the phase detector.
    Type: Grant
    Filed: February 10, 1998
    Date of Patent: November 21, 2000
    Assignee: Tektronix, Inc.
    Inventors: Gilbert A. Hoffman, Scott Zink
  • Patent number: 6094102
    Abstract: A frequency stabilizer circuit in the form of a charge-pump phase-lock loop utilizing a MEMS capacitance device, preferably a tunable MEMS capacitor or a MEMS capacitor bank, which more rapid and with a greater precision determine the phase and frequency of a carrier signal so that it can be extracted, providing an information signal of interest. Such MEMS devices have the added advantage of providing linear capacitance, low insertion losses, higher isolation and high reliability, they run on low power and permit the entire circuit to be fabricated on a common substrate. The use of the MEMS capacitance device reduces unwanted harmonics generated by the circuit's charge pump allowing the filtering requirements to be relaxed or perhaps eliminated.
    Type: Grant
    Filed: April 30, 1999
    Date of Patent: July 25, 2000
    Assignee: Rockwell Science Center, LLC
    Inventors: Mau Chung F. Chang, Henry O. Marcy, 5th, Kenneth D. Pedrotti, David R. Pehlke, Charles W. Seabury, Jun J. Yao, James L. Bartlett, J. L. Julian Tham, Deepak Mehrotra
  • Patent number: 5898531
    Abstract: Input data is modulated, a two-valued signal regarding a signal of a specific frequency is generated, and a logical arithmetic operation between the modulation data and the two-valued signal is executed. In accordance with the result of the logical arithmetic operation, the specific frequency component in the modulation data is detected. The modulating operation is controlled in accordance with the detection result. As mentioned above, the specific frequency component in the modulation data is detected by the logical arithmetic operation between the modulation data and the two-valued signal. By controlling the modulator on the basis of the detection result, the specific frequency component in the modulation data can be detected by a simple construction. For example, an amount of specific frequency component in the modulation data can be adjusted.
    Type: Grant
    Filed: August 29, 1995
    Date of Patent: April 27, 1999
    Assignee: Cannon Kabushiki Kaisha
    Inventor: Shingo Nozawa
  • Patent number: 5877907
    Abstract: An apparatus for demodulating a data signal read from a recording medium, in which data is recorded on at least a portion of the recording medium. The data is recorded using a recording system having a substantially constant linear velocity. In this manner, the recording medium is rotated at a substantially constant speed during the reading of data signals such that one of a frequency and an amplitude of the read data signal varies. The apparatus includes a signal processor for processing the read data signal in response to a change in one of the frequency and amplitude to produce a processed data signal suitable for demodulation. Once the processed data signal is produced, a demodulator operates to demodulate the data signal and to produce a demodulated data signal.
    Type: Grant
    Filed: September 30, 1996
    Date of Patent: March 2, 1999
    Assignee: Fujitsu Limited
    Inventors: Hideaki Tanishima, Noriko Tomita, Masato Tomita
  • Patent number: 5729828
    Abstract: A frequency processing circuit has a suppressing circuit for suppressing a lower sideband wave of an input FM signal whose frequency is modulated, a frequency conversion circuit for converting the frequency of an output of the suppressing circuit, and an emphasizing circuit for emphasizing a lower sideband wave of an output of the frequency conversion circuit. The emphasizing circuit emphasizes a share of the amount of the wave suppressed by the suppressing circuit.
    Type: Grant
    Filed: March 7, 1994
    Date of Patent: March 17, 1998
    Assignee: Canon Kabushiki Kaisha
    Inventors: Makoto Goda, Shinichi Yamashita
  • Patent number: 5715353
    Abstract: A playback/recording modulating-demodulating device, having a voltage-controlled oscillator (VCO), a voltage-current inverter (VCI), a band-pass filter, an amplitude limiter, and a phase-locked loop. In playback mode, the playback input signal is applied to the band-pass filter, the phase-locked loop is activated, and the VCI is set to produce a reference signal which controls the band-pass filter to tune the playback input signal. The tuned playback signal is applied to the amplitude limiter which produces an amplitude-limited signal which is applied to the phase-locked loop to produce a demodulated playback output signal. In record mode, the phase-locked loop is deactivated, the VCO produces a signal having a frequency which varies according to the voltage of a record input signal, and the VCI outputs a current control signal, having an output current related to the voltage of the record input signal, which is applied to the band-pass filter to control its bandwidth.
    Type: Grant
    Filed: May 31, 1996
    Date of Patent: February 3, 1998
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Chun-Sub Kim, Yong-Serk Kim
  • Patent number: 5694080
    Abstract: A delay-type FM demodulation circuit of this invention has an object to satisfactorily remove a harmonic wave in an arithmetic calculation output signal even if an LPF having relatively moderate stopping characteristics is used. The delay-type FM demodulation circuit includes first to third delay circuits for obtaining first to third signals obtained by times (e.g., 1/8, 1/4, and 3/8) which sequentially increase within a time shorter than 1/2 which is a signal period obtained when an FM-modulated input signal is positively deviated by a maximum frequency, a first multiplication circuit for multiplying the input signal and the first signal, a second multiplication circuit for multiplying the second signal and the third signal, and an addition circuit for adding an output signal from the first multiplication circuit and an output signal from the second multiplication circuit.
    Type: Grant
    Filed: October 16, 1996
    Date of Patent: December 2, 1997
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Michihiro Adachi
  • Patent number: 5655047
    Abstract: A video signal frequency modulator having an automatic control function includes a reference generator for generating a sync tip level signal and a white peak level signal, a first switch for selecting one of the sync tip level signal, white peak level signal or a clamped video signal according to a mode control signal, a variable gain amplifier for amplifying the output of the first switch to a predetermined gain and converting the amplified result into a current, an adder for adding the output of the variable gain amplifier with a predetermined set value, an oscillator for frequency-modulating the output of the adder, a frequency detector for shaping and frequency-dividing the output of the oscillator, a microcomputer for comparing the output of the frequency detector with a predetermined reference frequency and outputting first and second control data and the mode control signal, a carrier frequency setting portion for controlling the magnitude of the predetermined set value according to the first control
    Type: Grant
    Filed: September 12, 1996
    Date of Patent: August 5, 1997
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Yun-jong Hyun, Jong-ho Ahn
  • Patent number: 5592132
    Abstract: In a frequency modulator (1) having an adjusting circuit by which frequency modulator an applied luminance signal of a color video signal that contains synchronization pulses is frequency modulated, while the chrominance signal of the color video signal is modulated on a carrier, that has a quiescent frequency if no color information is available. A capacitor is provided for an automatic mode of operation, and is charged or discharged, respectively, in dependence on the period duration of the modulator output signal and in dependence on the period duration of the quiescent frequency of the chrominance carrier.
    Type: Grant
    Filed: May 4, 1995
    Date of Patent: January 7, 1997
    Assignee: U.S. Philips Corporation
    Inventors: Holger Ernst, Holger Moll
  • Patent number: 5517159
    Abstract: A frequency modulating system for frequency-modulating an input signal with a predetermined carrier frequency comprising a controller circuit and a frequency modulator is provided. The controller circuit includes an automatic frequency detecting circuit, a voltage controlled oscillator, an error current generator, a feedback clamping circuit, a deviation current generator, and an adder circuit generating a frequency deviation/carrier frequency correction signal provided to the frequency modulator. The frequency modulator modulates the frequency in response to an output of the controller circuit and includes an oscillator having the same structure as that of the voltage controlled oscillator.
    Type: Grant
    Filed: April 24, 1995
    Date of Patent: May 14, 1996
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Myoungchun Hwang
  • Patent number: 5506547
    Abstract: A frequency modulation circuit which varies the resonance frequency of an LC resonance circuit, and which corresponds to the frequency modulation conversions of all TV methods with a simple constitution. Each of a plurality of passive element series circuits for varying a time constant of the LC resonance circuit is composed of, for instance, a capacitor and a resistor, which is switched and controlled by connecting to or separating from the LC resonance circuit by a switching circuit such as a transistor. Thereby, the oscillation frequency of the LC resonance circuit can be easily converted to a predetermined frequency.
    Type: Grant
    Filed: April 4, 1995
    Date of Patent: April 9, 1996
    Assignee: Sony Corporation
    Inventor: Nobuyuki Ishikawa
  • Patent number: 5504463
    Abstract: A frequency modulating system for frequency-modulating an input signal with a predetermined carrier frequency comprising a controller circuit and a frequency modulator is provided. The controller circuit includes an automatic frequency detecting circuit, a voltage controlled oscillator, an error current generator, a feedback clamping circuit, a deviation current generator, and an adder circuit generating a frequency deviation/carrier frequency correction signal provided to the frequency modulator. The frequency modulator modulates the frequency in response to an output of the controller circuit and includes an oscillator having the same structure as that of the voltage controlled oscillator.
    Type: Grant
    Filed: April 24, 1996
    Date of Patent: April 2, 1996
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Myoungchun Hwang
  • Patent number: 5465071
    Abstract: An information signal processing apparatus according to the present invention is arranged to receive as an input a frequency-modulated information signal having a predetermined frequency band, form a sample pulse signal by sampling the input frequency-modulated information signal in accordance with a clock signal having a first frequency which is selected so that a frequency which is 1/n times (n is a positive integer) a frequency of half the first frequency is positioned in a frequency band lower than the frequency band of the input frequency-modulated information signal and so that a frequency which is (n+1) times (n is a positive integer) the frequency of half the first frequency is positioned in a frequency band higher than the frequency band of the input frequency-modulated information signal, and demodulate the frequency-modulated information signal by performing computing processing of the formed sample pulse signal in accordance with the clock signal having the first frequency.
    Type: Grant
    Filed: January 27, 1995
    Date of Patent: November 7, 1995
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takashi Kobayashi, Shinichi Hatae
  • Patent number: 5461339
    Abstract: A simplified apparatus for processing frequency modulated signals is disclosed which is equipped with a frequency characteristic correction function and an inversion prevention function. An input signal is processed with different parameters within a cosine equalizer so that the cosine equalizer outputs two different signals, i.e., one frequency characteristic of which was corrected and the other which was processed with no consideration on frequency characteristic but aiming at restoring lost zero cross points. From the two signals, compensation signal generating means generates a compensation signal which is necessary to restore the lost zero cross points. The frequency characteristic-corrected signal from the cosine equalizer is delayed in a delay line for a period of time required to generate the compensation signal.
    Type: Grant
    Filed: April 13, 1993
    Date of Patent: October 24, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Tsutomu Kawano
  • Patent number: 5442451
    Abstract: A video tape recorder includes a cylinder provided to rotate about its axis. A magnetic tape moves along a portion of the cylinder surface such that the cylinder surface obliquely traverses the magnetic tape. At least one pair of magnetic heads are mounted on the cylinder surface for recording and reproducing video signal on the tape, and another pair of magnetic heads are mounted on the cylinder for recording and reproducing audio signal on the tape.
    Type: Grant
    Filed: April 2, 1987
    Date of Patent: August 15, 1995
    Assignees: Matsushita Electric Industrial Co., Ltd., Hitachi, Ltd.
    Inventor: Shuzo Hitotsumachi