Patents by Inventor Chandrakant B. Patel
Chandrakant B. Patel has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7038732Abstract: A DTV signal has a plural-data-segment frame header including complementary first and second ghost-cancellation reference signals differentially delayed by the duration of two NTSC horizontal scan lines. A receiver for such DTV signal has an adaptive equalizer for baseband symbol code with kernel weights calculated by a computer operative on the equalizer response after comb filtering. The comb filter combines the equalizer response as differentially delayed by the duration of two NTSC horizontal scan lines to cancel artifacts of co-channel NTSC interference in the comb filtered equalizer response supplied to the computer. This reduces the undesirable influence of such artifacts on equalization to reduce intersymbol interference.Type: GrantFiled: May 11, 1999Date of Patent: May 2, 2006Assignee: Samsung Electronics Company, Ltd.Inventors: Allen L. Limberg, Chandrakant B. Patel
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Patent number: 6803970Abstract: A radio receiver for receiving a selected digital TV signal uses final intermediate frequency signals the carrier frequencies of which are multiples of symbol rate. The radio receiver has a match filter receptive of rectified samples of digitized intermediate-frequency signal and responsive to the amplitude of the intermediate-frequency carrier being modulated in accordance with the field synchronization code group to generate a pulsed response to the beginning of each data field. This pulsed response is used to determine when data segment synchronization information should occur, so its detection is more certain to be accurate and data segment synchronization is more rapidly determined. Symbol synchronization is rapidly inferred from the field synchronization and data segment synchronization, so that the samples in each data line can be counted.Type: GrantFiled: June 22, 1999Date of Patent: October 12, 2004Assignee: Samsung Electronics Co., Ltd.Inventors: Allen LeRoy Limberg, Chandrakant B. Patel
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Publication number: 20030236165Abstract: Product package, comprising a data storage device, packaging material, and an authentication system. The authentication system comprises first and second coatings coated on the storage device and the packaging material. One of the coatings comprises chromogenic microcapsules capable of reacting to produce color. The other coating comprises color developer. The coatings can be bonded to each other or a composite coating can be a self-contained color former such as on the storage device. The invention further comprises methods of affirming authenticity of a data storage device. The method comprises applying to the storage device a color-reactable coating which can react with a color-producing second composition, packaging the storage device to provide a closed and sealed packaged, opening the package, and concurrent with or after opening the package, reacting the chemical compositions to produce the color as an indication of authenticity of the data storage device.Type: ApplicationFiled: June 25, 2002Publication date: December 25, 2003Applicant: Appleton Papers Inc.Inventors: Jan L. Peebles, Chandrakant B. Patel
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Patent number: 6545728Abstract: Receiving apparatus for digital television signals digitizes a final intermediate frequency signal supplied from a triple-conversion radio receiver and synchrodynes the digitized final intermediate frequency signal to baseband. The triple-conversion radio receiver selects one of a plurality of digital television signals for upconversion to that portion of the electromagnetic frequency spectrum above the channels that are used for television broadcasting, amplifies a first intermediate-frequency signal in a first intermediate frequency band generated by that upconversion, amplifies a second intermediate-frequency signal in a second intermediate frequency band generated by downconverting the amplified first intermediate-frequency signal, and supplies a third intermediate-frequency signal in a third intermediate frequency band generated by downconverting the amplified second intermediate-frequency signal.Type: GrantFiled: April 14, 1999Date of Patent: April 8, 2003Assignee: Samsung Electronics Co., Ltd.Inventors: Chandrakant B. Patel, Allen LeRoy Limberg
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Patent number: 6535553Abstract: A digital communications radio receiver, as for television, digitizes a final intermediate-frequency signal offset from zero frequency no more than a few megahertz. This digitized final I-F signal is passed through an adaptive equalizer before being synchrodyned to baseband in the digital regime, which adaptive equalizer has its weighting coefficients determined by comparing I-F signal as received with possible multipath with ideal I-F signal free from multipath distortion. Decision feedback for adjusting the filtering coefficients of the equalizer is described, which is based on the ideal baseband signal being re-modulated onto final I-F carrier and compared to the received signal as translated in frequency to provide the final I-F signal.Type: GrantFiled: June 18, 1999Date of Patent: March 18, 2003Assignee: Samsung Electronics Co., Ltd.Inventors: Allen LeRoy Limberg, Chandrakant B. Patel
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Patent number: 6526101Abstract: Apparatus for reproducing data from a selected digital television signal, transmitted in packet form as quadrature-amplitude-modulation (QAM) of a carrier, has a tuner for selecting a digital television signal and converting it to a final intermediate-frequency signal, which is digitized by an analog-to-digital converter before synchrodyning to baseband in the digital regime. QAM synchrodyning circuitry responsive to the digitized final intermediate-frequency signal generates real and imaginary digital sample streams of QAM symbol code, by synchrodyning the final IF signal to baseband in the digital regime. Symbol decoding circuitry responsive to the real and imaginary digital sample streams of QAM symbol coding generates a digital data stream. Data synchronization recovery circuitry recovers data synchronizing information included in the digital data stream.Type: GrantFiled: December 22, 1998Date of Patent: February 25, 2003Assignee: Samsung Electronics Co., Ltd.Inventor: Chandrakant B. Patel
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Patent number: 6512555Abstract: Apparatus for reproducing data from a selected digital television signal, transmitted in packet form as vestigial-sideband (VSB) amplitude-modulation (AM) of a carrier, has a tuner for selecting a digital television signal and converting it to a final intermediate-frequency signal, which is digitized by an analog-to-digital converter before synchrodyning to baseband in the digital regime. VSB synchrodyning circuitry synchrodynes the digitized final intermediate-frequency signal to baseband in the digital regime to generate in-phase and quadrature-phase baseband signals. The quadrature-phase baseband signal is lowpass filtered to generate an automatic frequency and phase control (AFPC) signal for controlling a local oscillator in the tuner, so that the in-phase baseband signal comprises digitized VSB symbol coding. Symbol decoding circuitry responsive to the VSB symbol coding generates a digital data stream.Type: GrantFiled: August 16, 1999Date of Patent: January 28, 2003Assignee: Samsung Electronics Co., Ltd.Inventors: Chandrakant B. Patel, Allen LeRoy Limberg
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Patent number: 6426780Abstract: A digital television receiver converts very-high-frequency intermediate-frequency digital television signal to a band with uppermost frequency in the lower portion of the high-frequency range. This facilitates RLC analog filtering, such as a Butterworth-Thomson-transition filter or a bridged-T trap filter, being used for suppressing the frequency-modulated audio carrier of co-channel NTSC analog television signal prior to the digital television signal being synchrodyned to baseband for recovering symbol code. The delay distortion introduced by this analog filtering is compensated for in substantial part in surface-acoustic-wave bandpass filtering of the very-high-frequency intermediate-frequency digital television signals. Remnant delay distortion is reduced by channel equalization filtering carried out in the digital regime.Type: GrantFiled: September 15, 1999Date of Patent: July 30, 2002Assignee: Samsung Electronics Co., Ltd.Inventors: Allen LeRoy Limberg, Chandrakant B. Patel
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Patent number: 6396542Abstract: A television receiver receives HDTV video signals and scan converts them to a lower line scanning rate with field-to-field interlace. This scan conversion is done to conserve the power consumption by the magnetic deflection system for the kinescope, which has a display screen with a 16:9 aspect ratio and a dot pitch for displaying a 480 scan line frame. The receiver receives scan converts NTSC video signals using time compression circuitry to present them in variants of letter-box form in which the images fill the full height of the display screen, but not its full width.Type: GrantFiled: August 2, 1996Date of Patent: May 28, 2002Assignee: Samsung Electronics Co., Ltd.Inventor: Chandrakant B. Patel
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Patent number: 6377312Abstract: In a radio receiver for digital transmissions, an adaptive channel equalizer is clocked at a sampling rate higher than symbol rate by a factor k and employs decision feedback for adjusting the coefficients of its component filters. The channel equalizer response as supplied at the sampling rate k times symbol rate is decimated to symbol rate and quantized to generate a signal estimating the symbols transmitted to the receiver. The channel equalizer response as supplied at the sampling rate k times symbol rate is compared to the signal estimating the transmitted symbols as re-sampled to the sampling rate k times symbol rate, in order to develop decision-feedback error signal at the sampling rate k times symbol rate. This decision-feedback error signal has sufficient digital bandwidth to permit fractionally spaced equalization with all coefficients being optimally adjusted.Type: GrantFiled: August 13, 1999Date of Patent: April 23, 2002Assignee: Samsung Electronics Co., Ltd.Inventors: Allen LeRoy Limberg, Chandrakant B. Patel
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Patent number: 6333767Abstract: A radio receiver uses the same tuner for receiving a selected digital television (DTV) signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal. The tuner supplies a final IF signal in a 6-MHz-wide frequency band, the lowest frequency of which is not appreciably more than 2.69 MHz. The final IF signal is digitized at a rate that is a multiple of both the symbol frequencies of the QAM and VSB signals, for synchrodyning to baseband, with the 2.69 MHz difference between the carrier frequencies of QAM and VSB signals being taken into account in the digital synchrodyning circuitry. The carrier frequencies of the QAM and VSB final IF signals are regulated to be submultiples of the multiple of both the symbol frequencies of the QAM and VSB signals by applying automatic frequency and phase control signals developed in the digital circuitry to a local oscillator of the tuner.Type: GrantFiled: April 28, 1998Date of Patent: December 25, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Chandrakant B. Patel, Allen LeRoy Limberg
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Patent number: 6313885Abstract: During the reception of VSB DTV signal, the channel equalizer for a QAM/VSB DTV signal receiver the equalizer is operated to equalize only the real sample stream of VSB symbol code, rather than being operated as a complex equalizer. During the reception of QAM DTV signal, the real sample stream of QAM symbol code and the imaginary sample stream of QAM symbol code are time-division-multiplexed together on an alternate sample basis to generate input signal for the channel equalizer, which is operated as a dual-phase filter. After equalization, the time-division-multiplexed real and imaginary samples of QAM symbol code are de-multiplexed to recover parallel real and imaginary sample streams of QAM symbol code that are independent of each other, but have been subjected to similar equalization. Supposing that the QAM DTV symbol code rate is half the VSB DTV symbol code rate, the minimum sampling rate for operation of the channel equalizer is the same for both types of symbol code.Type: GrantFiled: November 15, 1999Date of Patent: November 6, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Chandrakant B. Patel, Allen LeRoy Limberg
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Patent number: 6313882Abstract: Television signal reception apparatus for receiving a television signal selected from among transmitted television signals of different types includes a respective receiver portion for each of the different types. Responsive to its respective type of television signal being received, each receiver portion supplies digitized baseband signal to adaptive digital filter circuitry shared by each receiver portion. The adaptive digital filter circuitry is operated for suppressing ghosts in that digitized baseband signal.Type: GrantFiled: December 22, 1998Date of Patent: November 6, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Allen LeRoy Limberg, Chandrakant B. Patel
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Patent number: 6300984Abstract: Training signal for channel equalization is located in the initial data segment of each DTV data field or in the nineteenth scan line of each NTSC field. The training signal comprises a pseudo-random noise sequence near the conclusion of the initial data segment of each DTV data field or the nineteenth scan line of each NTSC field and an earlier pseudo-random noise sequence. The later pseudo-random noise sequence is used in a television receiver for detecting pre-ghosts and the earlier pseudo-random noise sequence is used in a television receiver for detecting post-ghosts.Type: GrantFiled: December 22, 1998Date of Patent: October 9, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Allen LeRoy Limberg, Chandrakant B. Patel
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Patent number: 6222592Abstract: An adaptive channel equalizer for a digital television receiver includes memory for storing channel characterization information for each received channel, from each time the channel is tuned to until the next time the same channel is tuned to. The stored information is retained even if operating power to the receiver is interrupted. Whenever operating power is restored to the receiver after interruption and whenever a channel is tuned to again after having tuned to another channel, the previously stored channel characterization for the currently tuned channel is retrieved from memory. The retrieved channel characterization is used to calculate initial filter coefficients for the adaptive channel equalizer.Type: GrantFiled: October 9, 1998Date of Patent: April 24, 2001Assignee: Samsung Electronics Co., Ltd.Inventor: Chandrakant B. Patel
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Patent number: 6211924Abstract: A radio receiver uses the same tuner for receiving a selected digital television (DTV) signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal. The final IF signal is digitized at a rate that is a multiple of both the symbol frequencies of the QAM and VSB signals, for synchrodyning to baseband. The carrier frequencies of the QAM and VSB final IF signals are regulated to be submultiples of the multiple of both the symbol frequencies of the QAM and VSB signals by applying automatic frequency and phase control (AFPC) signals developed in the digital circuitry to a local oscillator of the tuner. Baseband DTV signals obtained by synchrodyning the final IF signals have a sample rate higher than symbol rate to facilitate symbol synchronization. The baseband DTV signals are decimated to symbol rate before performing channel equalization to reduce the number of multipliers required in the channel equalization filter.Type: GrantFiled: October 12, 1999Date of Patent: April 3, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Chandrakant B. Patel, Allen LeRoy Limberg
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Patent number: 6184942Abstract: Methods for operating an adaptive receiver for receiving a selected DTV signal, which can be either a quadrature-amplitude-modulation (QAM) signal or a vestigial sideband (VSB) signal. The adaptive receiver includes adaptive symbol decoding circuitry for adaptively decoding baseband signal encoded in different signal formats at selected different code rates to provide a decoded output signal, an adaptive deinterleaver for deinterleaving the decoded output signal in accordance with a deinterleaving function selected from a plurality of deinterleaving functions, and an adaptive error decoder for detecting and correcting errors in the deinterleaver output signal.Type: GrantFiled: August 16, 1999Date of Patent: February 6, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Chandrakant B. Patel, Allen LeRoy Limberg
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Patent number: 6137545Abstract: A radio receiver uses the same tuner for receiving a selected wideband digital signal of at least a few megahertz bandwidth, such as a digital television (DTV) signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal accompanied by an unmodulated pilot carrier signal; and a second transmission standard specifies quadrature amplitude modulation. It is determined at the receiver which of respective modulation formats specified for the various transmission standards is employed for transmitting the wideband digital signal being received. The wideband digital signal is demodulated to produce a demodulated signal, demodulation be done according to a demodulation format suitable for demodulating the modulation format determined to be employed for transmitting the wideband digital signal.Type: GrantFiled: August 16, 1999Date of Patent: October 24, 2000Assignee: Samsung Electronics Co., Ltd.Inventors: Chandrakant B. Patel, Allen LeRoy Limberg
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Patent number: 6134373Abstract: An encoder separates luminance and chrominance signal components of a composite video signal. The frame-to-frame changes in the luminance signal are detected, and a motion signal is derived therefrom. The higher frequency portion of the luminance signal is adaptively de-emphasized in amplitude and folded into the spectrum of the lower frequency portion of the luminance signal, to generate a folded-spectrum luminance signal for modulating the frequency of a luma carrier. In a combined signal, suitable for magnetic recording in accordance with a modified VHS standard, the chrominance signal is translated in frequency to generate a color-under signal in a frequency band below that occupied by the FM luma carrier.Type: GrantFiled: November 4, 1991Date of Patent: October 17, 2000Assignee: Samsung Electronics Co., Ltd.Inventors: Christopher H. Strolle, Chandrakant B. Patel, Werner F. Wedam, Jung Wan Ko, Raymond Schnitzler, Jong Kyung Yun
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Patent number: RE38456Abstract: A radio receiver uses the same tuner for receiving a selected digital television (DTV) signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal. The final IF signal is digitized at a rate that is a multiple of both the symbol frequencies of the QAM and VSB signals, for synchrodyning to baseband. The carrier frequencies of the QAM and VSB final IF signals are regulated to be submultiples of the multiple of both the symbol frequencies of the QAM and VSB signals by applying automatic frequency and phase control (AFPC) signals developed in the digital circuitry to a local oscillator of the tuner. Baseband DTV signals obtained by synchrodyning the final IF signals have a sample rate higher than symbol rate to facilitate symbol synchronization. The baseband DTV signals are decimated to symbol rate before performing channel equalization to reduce the number of multipliers required in the channel equalization filter.Type: GrantFiled: October 11, 2001Date of Patent: March 9, 2004Assignee: Samsung Electronics Co., Ltd.Inventors: Chandrakant B. Patel, Allen LeRoy Limberg