Modulator Patents (Class 348/724)
  • Patent number: 6633340
    Abstract: A video signal processor reduces the deterioration of image quality due to the superposition of noise on a sync signal included in a luminance signal. A frequency discriminator outputs a first error signal if a ratio of the frequency of a frequency-modulated signal during a sync-signal interval to the frequency of a reference frequency signal is smaller than a predetermined ratio. Alternatively, the discriminator outputs a second error signal if the ratio is greater than the predetermined ratio. If the first error signal has been input to a frequency controller a preset number of times or more during an interval before the second error signal is input thereto, the controller instructs a frequency modulator to increase the frequency of the frequency-modulated signal.
    Type: Grant
    Filed: October 23, 2000
    Date of Patent: October 14, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Atsushi Ohara, Takuji Yoneda
  • Publication number: 20030169338
    Abstract: The invention relates to a method of and an apparatus for multiplexing a number of video signals.
    Type: Application
    Filed: November 7, 2002
    Publication date: September 11, 2003
    Inventors: Franciscus Herman Maria Bergen, Jennifer Lynn Randall, Bruce Daniel Magid
  • Publication number: 20030156228
    Abstract: An RF modulator includes a C/L delay compensation function of compensating for a delay of a luminance signal with respect to a chrominance signal occurring during demodulating a video signal in a TV set. The RF modulator includes a C/L delay compensation unit delaying a luminance signal by 170nsec and combining the delayed luminance signal with a chrominance signal to output a composite image signal having a C/l delay of −170nsec and a frequency modulation unit modulating the video signal received from the C/L delay compensation unit into a high frequency signal of a predetermined broadcasting channel in a single module or package. The RF modulator outputs a video signal having the luminance signal delayed by 170nsec with respect to the chrominance signal and complies with a C/L delay standard without adding any additional C/L delay compensation unit to the RF modulator.
    Type: Application
    Filed: February 19, 2003
    Publication date: August 21, 2003
    Applicant: Samsung Electro-Mechanics Co., Ltd.
    Inventors: Jong Jin Lee, Sang Suk Kim, Chae Dong Go, Youn Joong Lee, Kyoung Soo Kwon
  • Publication number: 20030151697
    Abstract: A wireless transmitting and receiving apparatus for wirelessly transmitting a video signal to a remote display apparatus, a transceiver therefor, and a channel determining method for determining a channel to be used in transmitting and receiving a video signal between transmitting and receiving apparatuses are provided. The video signal transmitting apparatus comprises a super heterodyne-type transmitter which selects one of a plurality of channels, modulates a video signal to be transmitted, and provides the modulated signal to an antenna; and a frequency band and channel selector which controls a modulation and demodulation frequency of the transmitter. The apparatus enables wireless transmission and reception of a video signal between a video signal processing apparatus and a remote display apparatus.
    Type: Application
    Filed: September 5, 2002
    Publication date: August 14, 2003
    Applicant: SAMSUNG ELECTRONICS CO., LTD.
    Inventor: Yong-jun Lim
  • Patent number: 6600516
    Abstract: A digital radio frequency transmitter system having an input circuit for receiving digital signals to be amplified and transmitted. A digital-to-analog converter converts the digital signals into analog signals. A series circuit is provided including a radio frequency filter and a radio frequency amplifier located downstream from the converter and wherein the filter and the amplifier respectively introduce linear and non-linear distortions into the analog signals for transmission by the transmitter. A digital pre-correction circuit is located upstream from the digital-to-analog converter for pre-correcting the digital signals in a manner to compensate for at least some of the distortions. An analog pre-correction circuit is interposed between the digital-to-analog converter and the series circuit for pre-correcting the analog signals to additionally compensate for at least some of the distortions prior to application to the series circuit.
    Type: Grant
    Filed: April 21, 2000
    Date of Patent: July 29, 2003
    Assignee: Harris Corporation
    Inventors: David Christopher Danielsons, Paul Henry Mizwicki
  • Patent number: 6567132
    Abstract: An upconverter for converting IF television signals to VHF or UHF signals prior to broadcast is configured to process either analog or digital television signals. The upconverter identifies the type of incoming television signal and generates an appropriate reference signal depending on whether the incoming television signal is digital or analog. In an analog format, the reference signal is used by the modulator generating the IF signal to synchronize phase with the signals output by various other upconverters. In a digital format, the reference signal is used, for example, as a test signal for the upconversion circuit.
    Type: Grant
    Filed: March 10, 1999
    Date of Patent: May 20, 2003
    Assignee: General Instruments Corp.
    Inventors: Donald E. Groff, Marlin F. McGregor, Jr.
  • Patent number: 6559898
    Abstract: An encoder-modulator for coupling a digital baseband television signal to a VSB digital television receiver that includes filters, equalization circuitry, and forward error correction circuitry for correcting signal impairments that are below a given threshold. The encoder-modulator processes the baseband signal for low power transmission on an RF channel with less-than-nominal bandpass characteristics. A coaxial cable or other low noise communication link directly connects the RF signal to the RF input of the television receiver. Any errors or signal impairments in the transmitted signal that are below the predetermined threshold are corrected by the filters and equalization circuitry built into the VSB digital television receiver.
    Type: Grant
    Filed: April 27, 1999
    Date of Patent: May 6, 2003
    Assignee: Zenith Electronics Corporation
    Inventors: Richard W. Citta, Raymond C. Hauge, Thomas P. Horwitz, Paul A. Snopko
  • Patent number: 6515609
    Abstract: A radio receiver comprises frequency translation means(20, 21, 22) for frequency down converting an input signal to an intermediate signal, digital channel selection filtering means including at least one analogue-to-digital converter(ADC)(32, 33), the ADC comprising an over-sampling quantizer(Q1, Q2) having a plurality of dynamically selectable quantization levels, and means(30, 31, 36) responsive to the characteristics of the input signal for adjusting the resolution of the ADC to the characteristics of the input signal. The ADC may comprise a Sigma-Delta ADC. The resolution may be adjusted by altering the over-sampling rate and/or selecting the number of quantization levels to handle the prevailing interference and the wanted signal.
    Type: Grant
    Filed: March 9, 2000
    Date of Patent: February 4, 2003
    Assignee: Koninklijke Philips Electronics N.V.
    Inventor: Timothy J. Moulsley
  • Patent number: 6515712
    Abstract: A signal distortion compensating apparatus and method in a digital TV translator are provided that extract a reference signal from a modulator output of a digital TV translator, and conduct a pre-correction based on the extracted reference signal to compensate for a signal distortion involved in the digital TV translator. The compensating apparatus can include a modulator that modulates an input signal while conducting a distortion pre-correction controlled by a control signal applied thereto on the input signal. The modulator outputs baseband signals divided from the input signal. A signal processing unit processes the signals outputted from the modulator, and transmits the resultant signal to subscribers. An auto correction unit compares the signal, which is outputted in a distorted state from the signal processing unit, with a reference signal derived from the baseband signals output by the modulator, and generates the control signal based on the result of the comparison.
    Type: Grant
    Filed: July 18, 2000
    Date of Patent: February 4, 2003
    Assignee: LG Information & Communications, Ltd.
    Inventor: Chang Seop Jeong
  • Patent number: 6473136
    Abstract: Motion information for an object and background information are broadcast-transmitted on a transmitting side. On a receiving side, the motion information and the background information are received, and one of a plurality of character models previously stored is selected. A character image is generated using the selected mode and the received motion information. The character image and the received background image are synthesized and displayed on one screen. The viewer can select a character of his or her own liking, and can view the broadcast-transmitted program as a program in which the particular character appears.
    Type: Grant
    Filed: December 8, 1999
    Date of Patent: October 29, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Hasegawa, Yoshito Nejime
  • Patent number: 6466277
    Abstract: A digital method and apparatus modulates a stream of digitized samples from a source, by a digital representation of a carrier to provide, for example, a 6 MHz bandwidth television signal selectively centered either at 63 MHz (Channel 3), 69 MHz (Channel 4) or 5.38 MHz IF (baseband). More particularly the method includes first resampling the stream of digitized samples and then modulating the resampled stream of samples with a repeating short sequence of complex values, which complex values represent a digitized exponential carrier.
    Type: Grant
    Filed: August 24, 1999
    Date of Patent: October 15, 2002
    Assignee: Thomson Licensing S.A.
    Inventor: David Lowell McNeely
  • Publication number: 20020145679
    Abstract: A tuner of a digital television signal translator tunes to receive an RF digital television signal on a first selected television channel. A demodulator provides a baseband digital television signal from the RF digital television signal to which the tuner is tuned. The baseband television signal includes a data component identifying the first selected channel. A data replacer replaces the data component identifying the first selected channel with a data component identifying a second selected channel different from the first selected channel. The output of a modulator is modulated by the baseband television signal including the data component identifying the second selected channel for transmission as a digital television signal on the second selected channel.
    Type: Application
    Filed: April 6, 2001
    Publication date: October 10, 2002
    Inventors: Ernesto C. Barreyro, Timothy V. Frahm, Michael G. White
  • Publication number: 20020113905
    Abstract: A linear compensation system of a digital TV relay or other apparatus preferably includes a transmitting unit configured to modulate a data to an intermediate frequency (IF) signal, up convert the IF signal to an RF signal, and amplify the RF signal to a predetermined level using a high power amplifier (HPA). The system also includes a linear compensation unit to preferably directly vary a step size of an adaptive equalizer according to whether a signal-to-noise ratio (SNR) or an error vector magnitude (EVM) for an output signal of the HPA satisfies an advanced television systems committee (ATSC) or other standard. The linear compensation unit is thus configured to output an improved linear compensation coefficient to a modulator of the transmitting unit.
    Type: Application
    Filed: December 26, 2001
    Publication date: August 22, 2002
    Applicant: LG Electronics Inc.
    Inventor: Ji Won Lee
  • Patent number: 6437822
    Abstract: A method and apparatus are disclosed for generating an 8-level vestigial side band modulated radio frequency signal as a high definition television test signal. The invention utilizes the above in connection with a single ISA bus computer board that may be utilized in a personal computer for generating signals used to demonstrate HDTV products without the need for over the air HDTV broadcast signals.
    Type: Grant
    Filed: March 30, 2000
    Date of Patent: August 20, 2002
    Assignee: Sencore, Inc.
    Inventor: Michael I. Stolen
  • Patent number: 6433830
    Abstract: The proposed phase lock technique uses various feedback loops to lock the frequency and phase of a CATV modulator output signal to that of an off-air signal without directly measuring the output frequency. One embodiment includes a tuner for receiving the off-air signal and generating an intermediate frequency signal and a phase-frequency detector for comparing the frequency and phase of the intermediate frequency signal generated by the tuner with the frequency and phase of an intermediate frequency signal generated by the modulator based on a reference input signal. The output of the phase-frequency detector is used to control the reference input signal into the modulator and the reference input signal to the tuner such that the frequency and phase of the modulator output signal is locked to the frequency and phase of the received off-air signal.
    Type: Grant
    Filed: June 14, 1999
    Date of Patent: August 13, 2002
    Assignee: General Instrument Corporation
    Inventors: Donald Groff, Edgar Rhodes
  • Publication number: 20020080285
    Abstract: At the transmitter side, carrier waves are modulated according to an input signal for producing relevant signal points in a signal space diagram. The input signal is divided into, two, first and second, data streams. The signal points are divided into signal point groups to which data of the first data stream are assigned. Also, data of the second data stream are assigned to the signal points of each signal point group. A difference in the transmission error rate between first and second data streams is developed by shifting the signal points to other positions in the space diagram expressed at least in the polar coordinate system. At the receiver side, the first and/or second data streams can be reconstructed from a received signal. In TV broadcast service, a TV signal is divided by a transmitter into, low and high, frequency band components which are designated as a first and a second data streams respectively.
    Type: Application
    Filed: December 21, 2000
    Publication date: June 27, 2002
    Inventor: Mitsuaki Oshima
  • Patent number: 6411342
    Abstract: A signal of a vestigial sideband modulated wave is generated by use of a first oscillator, an amplitude-modulator and a surface acoustic wave filter for vestigial sideband filtering at a frequency being higher than the carrier frequency of a video signal, the signal is frequency-converted to a given transmission channel by use of a first PLL frequency synthesizer, a first control circuit, a frequency converter and a filter.
    Type: Grant
    Filed: February 2, 1998
    Date of Patent: June 25, 2002
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Akihiro Tatsuta
  • Patent number: 6388717
    Abstract: A digital television transmitting system is presented having a recovery circuit for recovering non-return to zero (NRZ) data pulses and transport clock pulses from a biphase-mark serial data pulse stream and wherein the recovered NRZ data pulses and the recovered transport clock pulses are applied to modulation and amplifying circuits for broadcasting by an antenna. The recovery circuit includes a first circuit for receiving the biphase-mark serial pulse stream and providing therefrom a train of first clock pulses wherein the rising edge of each the biphase-mark pulse corresponds with a rising edge of one of the first clock pulses. A second circuit receives the biphase-mark serial data pulses and the first clock pulses for providing therefrom a train of de-serialized data pulses each having a rising edge corresponding with a rising edge of one of the first clock pulses.
    Type: Grant
    Filed: January 20, 1999
    Date of Patent: May 14, 2002
    Assignee: Harris Corporation
    Inventor: Joseph Lee Seccia
  • Publication number: 20020047940
    Abstract: A modulation factor is kept immune from the influence of temperature variations. A modulator is provided with an operational amplifier to one of whose input ends are inputted video signals and to the other is applied a reference voltage and a video mixer into which are entered carrier wave signals and video signals amplified by the operational amplifier, wherein the reference voltage is raised or lowered as the gain of the video mixer increases or decreases, respectively, with a variation in temperature.
    Type: Application
    Filed: October 16, 2001
    Publication date: April 25, 2002
    Applicant: Alps Electric Co., Ltd
    Inventors: Yasuharu Kudo, Etsuya Shibata
  • Patent number: 6317167
    Abstract: Digital remodulation systems typically include digital to analog converters which have an inherent undesirable sin(x)/x frequency response. Digital remodulated signals are typically high frequency and thus not conducive to sin(x)/x pre-correction prior to digital to analog conversion. Described herein is apparatus and a method for pre-correcting the sin(x)/x roll off of the digital to analog converter in the digital signal path prior to the digital modulator which precedes the digital to analog converter. This apparatus corresponds to a cascading of spectrally symmetric and anti-symmetric transversal filters designed to compensate a relatively small portion of the frequency response of the resulting analog signal.
    Type: Grant
    Filed: August 24, 1999
    Date of Patent: November 13, 2001
    Assignee: Thomson Licensing S.A.
    Inventor: David Lowell McNeely
  • Patent number: 6313772
    Abstract: A method for generating digital carrier signals for application as the carrier to a digital modulator includes providing a first repeating sequence of complex values occurring at a given sample rate and upsampling these values to a higher sample rate. A second repeating sequence of complex values is provided, wherein respective complex values in the second repeating sequence occur at the higher sample rate. The second sequence of complex values is employed to modulate the upsampled first sequence of complex values and thereby provide the complex carrier signal.
    Type: Grant
    Filed: August 24, 1999
    Date of Patent: November 6, 2001
    Assignee: Thomson Licensing S.A.
    Inventor: David Lowell McNeely
  • Patent number: 6265949
    Abstract: A phase compensation apparatus and method for a digital modulator which is suitable for maintaining the optimum operating state of the modulator provided in a digital television repeater by reducing the phase distortion produced from the modulator.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: July 24, 2001
    Assignee: LG Information & Communications, Ltd.
    Inventor: Inn Yeal Oh
  • Patent number: 6219108
    Abstract: Radio receivers for receiving DTV signals, in accordance with the Advanced Television Systems Committee (ATSC) standard, or analog TV, in accordance with the National Television Sub-Committee (NTSC) standard, each use a single first detector for both types of signal. This single first detector supplies its output signals to an intermediate-frequency amplifier chain for DTV signals and to another intermediate-frequency amplifier chain for analog TV signals. The response of the intermediate-frequency amplifier chain for DTV signals is synchrodyned to baseband and supplied to symbol decoding circuitry. The response of the intermediate-frequency amplifier chain for analog TV signals is supplied to a video detector. In some of the radio receivers the sound carrier of the NTSC signal has a separate, further intermediate-frequency amplifier chain. The intermediate-frequency chain for DTV signals comprises an intitial portion which has reverse AGC, a following mixer, and a final portion which also has reverse AGC.
    Type: Grant
    Filed: January 6, 1998
    Date of Patent: April 17, 2001
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Allen LeRoy
  • Patent number: 6195797
    Abstract: A method and apparatus are provided for enabling multiple users to concurrently access a PC-based server in a home local area network using conventional TVs as display devices. A client system includes a TV, conventional input devices, such as a keyboard and a mouse, and a set top box for interfacing the TV to the network. The server maintains a system work area and multiple processes corresponding to user applications. The system work area is partitioned in the server into multiple independent, simultaneously active desktops, one desktop for each of the client systems. Individual processes are mapped to the appropriate desktop. Multiple frame buffers are maintained in the server, such that a different frame buffer is assigned to each client system. Each desktop is rendered within the server and stored in the corresponding frame buffer. The contents of each frame buffer are transmitted over a transmission medium to the set top box of the corresponding client system.
    Type: Grant
    Filed: February 6, 1998
    Date of Patent: February 27, 2001
    Inventor: Henry R. Williams, Jr.
  • Patent number: 6177963
    Abstract: A video signal distribution system comprises an interface device and video signal input means for receiving TV signals on broadcast channels connected to the interface device. A plurality of video appliances and a plurality of TV sets may be connected to the interface device such that the television sets are arranged to be remote from the plurality of video appliances. A person using the system has a remote control device that may be actuated to emit signals for selecting channels for viewing and to control the video appliances. Each of the television sets includes a repeater arranged to receive the control signals from the remote control device and form corresponding electrical control signals. The interface device receives the electrical control signals corresponding to a selected TV set and directs electrical control signals to a selected one of the plurality of video appliances to provide video signals to the television sets.
    Type: Grant
    Filed: December 1, 1997
    Date of Patent: January 23, 2001
    Assignee: Multiplex Technology, Inc.
    Inventors: Richard T. Foye, John B. Crosby
  • Patent number: 6175861
    Abstract: A method and apparatus are provided for enabling multiple users to concurrently access a PC-based server in a home local area network using conventional TVs as display devices. A client system includes a TV, conventional input devices, such as a keyboard and a mouse, and a set top box for interfacing the TV to the network. The server maintains a system work area and multiple processes corresponding to user applications. The system work area is partitioned in the server into multiple independent, simultaneously active desktops, one desktop for each of the client systems. Individual processes are mapped to the appropriate desktop. Multiple frame buffers are maintained in the server, such that a different frame buffer is assigned to each client system. Each desktop is rendered within the server and stored in the corresponding frame buffer. The contents of each frame buffer are transmitted over a transmission medium to the set top box of the corresponding client system.
    Type: Grant
    Filed: February 6, 1998
    Date of Patent: January 16, 2001
    Inventors: Henry R. Williams, Jr., David A. Ferris, Maurice B. Richard
  • Patent number: 6169584
    Abstract: The depth of modulation and the absolute RF carrier level of an amplitude-modulated video signal are automatically adjusted. For adjustment of the depth of modulation, a sync tip of the video signal is sampled, corrected and normalized to a reference level, e.g., a 50% video level. A reference pulse is inserted into the video signal, e.g., in a sync pulse or in lines 22 and/or 23 of the vertical blanking interval. The reference pulse is sampled and compared to the normalized sync tip pulse to determine an error. The error is converted to an adjustment signal for a charge pump which increases or decreases the depth of modulation accordingly. For adjustment of the absolute carrier level, the insertion of a reference pulse is not required. Instead, a reference value is stored in a memory and retrieved for comparison with the corrected sync tip pulse. An error term is computed and converted to an adjustment signal for a charge pump which increases or decreases the absolute carrier level accordingly.
    Type: Grant
    Filed: December 5, 1997
    Date of Patent: January 2, 2001
    Assignees: Motorola, Inc., General Instrument Corporation
    Inventors: Joseph B. Glaab, Alfred W. Stufflet
  • Patent number: 6061101
    Abstract: An apparatus to modulate the digital color signal using a simple circuit that utilizes neither multiplier nor ROMs to multiplying a sine wave and cosine wave. The digital color signal modulating apparatus includes a first selector, a second selector 3, and a third selector. The first selector and the second selector provide the U signal component and the V signal component of the digital color signal to the third selector at a half cycle, rate respectively. The third selector alternately selects one of those signals, which is combined with the sub-carrier wave. For both modulations with the sine wave and with the cosine wave, the input signal is inverted and the fourth selector selects the outputs of the through path and the inversion path in turn, thus producing the modulated outputs.
    Type: Grant
    Filed: May 28, 1997
    Date of Patent: May 9, 2000
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Akihiro Takei
  • Patent number: 6031583
    Abstract: A high frequency video isolation circuit comprising: a modulating signal source for producing a modulating signal having a frequency of several hundred megahertz; an input multiplier for multiplying the modulating signal with an input video signal having frequency components in a frequency range from about several hertz to about one hundred or more megahertz, to produce a modulated video signal having frequency components in a frequency range from about one hundred megahertz to about several hundred megahertz; a first isolation transformer having an input and an output, for transforming the modulated video signal from the input to the output; and an output multiplier for multiplying the transformed modulated video signal with the modulating signal to produce an isolated output video signal having the frequency components of the input video signal.
    Type: Grant
    Filed: June 9, 1998
    Date of Patent: February 29, 2000
    Assignee: Eastman Kodak Company
    Inventors: Sreeram Dhurjaty, Martin E. Trzcinski
  • Patent number: 6031576
    Abstract: A single, common HDTV transmitter transmits a digital composite signal including station signal information of all broadcast stations in a primary market. A broadband signal of e.g., 120 MHz is established, accommodating up to 20 permanent virtual circuits (PVCs) in the broadband signal. The station signals linked to the common transmitter are packetized and digitally compressed and delivered for broadcast in a selected transmission mode such as ATM. Tuning into a broadcaster's signal will be accomplished at a receiver location by a receiver decoding the PVC address permanently assigned to the respective station. The signal is decompressed to its original HDTV format by a receiver, which may comprise a personal computer or video card, to drive the HDTV display and audio system. Each receiver is equipped with a highly directional antenna aimed at a common an antenna broadcasting the composite signal from the common transmitter.
    Type: Grant
    Filed: September 8, 1997
    Date of Patent: February 29, 2000
    Inventor: Jacob L. Kuykendall, Jr.
  • Patent number: 6016169
    Abstract: A frequency modulation circuit which generates a frequency modulation signal responsive to a video input signal includes a programmable control circuit, an electrical flow control circuit, and an oscillation circuit. The programmable control circuit generates a plurality of electrical flow control signals responsive to an electronic data input. The electrical flow control circuit controls an electrical flow therethrough responsive to the plurality of electrical flow control signals. The oscillation circuits generates the frequency modulation signal responsive to the video input signal and responsive to the electrical flow through the electrical flow control circuit. Related methods are also disclosed.
    Type: Grant
    Filed: December 2, 1996
    Date of Patent: January 18, 2000
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Do-Sang Mok
  • Patent number: 5946047
    Abstract: A network system or terminal device utilizes a unique modulation scheme that enables the transmission of digital data over a wireless, cable or direct broadcast satellite TV channel without disturbing quality of television signals. A digital data stream of the network, for example, is transparently transmitted in the television channel in a superfluous sideband segment of the frequency spectrum using a technique, herein called vestigial quadrature modulation (VQM), that entails substituting the vestigial sideband of a conventional television signal with a sideband of a data-encoded signal, preferably being QAM-modulated. A sufficient portion of the television sideband spectrum displaced by the substituted data signal, e.g., to at least the 7.sup.th harmonic, is preserved for deriving sync information that is used both for clocking the digital data from the modulated data signal and for driving vertical and horizontal sync circuits of the television.
    Type: Grant
    Filed: March 12, 1997
    Date of Patent: August 31, 1999
    Assignee: Hybrid Networks, Inc.
    Inventor: William C Levan
  • Patent number: 5896182
    Abstract: Amplitude modulator comprising a differential input pair receiving a modulating input signal, and a Gilbert cell multiplying a carrier signal by the modulating input signal; anda second differential pair of transistors receiving the carrier signal, and the output signal of which is added to the output signal of the Gilbert cell.
    Type: Grant
    Filed: June 11, 1996
    Date of Patent: April 20, 1999
    Assignee: U.S. Philips Corporation
    Inventor: Philippe Klaeyle
  • Patent number: 5886752
    Abstract: A wideband phase and frequency modulator using a direct digital synthesis alias frequency band is described. The modulator is spurious free by the utilization of a fixed frequency at the output of the direct digital synthesizer wherein only certain submultiples of the clock frequency are used. Known frequency ratios relative to the clock frequency of the direct digital synthesizer (DDS) cause the DDS to function as a simple divider resulting in extremely low spurious levels when additional conditions are met. An additional frequency synthesizer may be utilized to achieve a tuning range since the DDS output is preferably held at a fixed frequency. At least one additional mixing operation is utilized for upconversion to a microwave frequency. Since fixed frequency ratios are used, implementation simpler than a full DDS may also be constructed consisting of digital modulators, multiplexers, digital to analog convertors, and filters.
    Type: Grant
    Filed: December 22, 1997
    Date of Patent: March 23, 1999
    Assignee: Rockwell International
    Inventor: Ray L. Cross
  • Patent number: 5877821
    Abstract: An apparatus (300, 400) and method are provided for multimedia communications, such as for video conferencing. One of the embodiments of the apparatus for multimedia input and control (300) includes a video input (310) to produce an input video signal; an audio input (320) to produce an input audio signal; a radio frequency modulator (350); a data/control input (330) to produce an input data signal; and a processor arrangement (360) responsive when operably coupled, through a set of program instructions, to produce a first processor signal to the radio frequency modulator to combine the input video signal with the input audio signal to form a composite audio/video signal, and the processor arrangement (360) further responsive to modulate the input data signal to form a modulated input data signal and produce a second processor signal to the radio frequency modulator to combine the input video signal with the modulated input data signal to form a combined video/data signal.
    Type: Grant
    Filed: January 30, 1997
    Date of Patent: March 2, 1999
    Assignee: Motorola, Inc.
    Inventors: Douglas J. Newlin, Timothy M. Burke
  • Patent number: 5877820
    Abstract: In optically transmitting a video signal comprised of luminance and chrominance signals which are frequency modulated to provide an FM luminance signal and an FM chrominance signal in respective adjacent frequency bands, such as, 6 to 20 MHz and 20 to 30 MHz, respectively, whereupon, infrared signals corresponding to the FM luminance and chrominance signals are output by respective emitting diodes, a carrier frequency for the FM chrominance signal is set, for example, between 25.93 and 26.08 MHz, so that the lower sideband wave of the FM chrominance signal is spaced by a substantial frequency from a frequency band in which a secondary distortion of the FM luminance signal is substantially generated. Further, the upper sideband wave of the FM chrominance signal is removed, as in a trap circuit, for ensuring that the transmitted FM chrominance signal will be accommodated in the respective frequency band therefor when its carrier frequency is set, as above.
    Type: Grant
    Filed: December 13, 1996
    Date of Patent: March 2, 1999
    Assignee: Sony Corporation
    Inventors: Toshikatsu Yamamuro, Tadashi Ezaki, Hiroshi Moriuchi
  • Patent number: 5875005
    Abstract: The method for generating a modulated television signal involves performing a first filtering and a second filtering to obtain two signals, one having a passband that is equal to complete passband and the other one having a passband that is equal to the sideband to be suppressed. The signal having a complete passband is amplitude-modulated with a video carrier, obtaining a first signal. The signal having a passband equal to the sideband to be suppressed is then divided into a first component and a second component, and the first component is phase-shifting by 90.degree. with respect to the second component. The first component is modulated with a video carrier that is phase shifted by 90.degree., obtaining a second signal. The second component of the signal having a passband equal to the sideband to be suppressed is modulated with the video carrier, obtaining a third signal. The second and third signals are then subjected to an algebraic sum, obtaining a fourth signal.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: February 23, 1999
    Assignee: M.B. International S.r.l.
    Inventor: Michele Bargauan
  • Patent number: 5822020
    Abstract: The method envisages performing a first filtering and a second filtering of a video signal to obtain two signals, one signal having a passband that is equal to the complete band and a bandwidth that is a function of the frequency, and another signal whose passband is equal to the side band to be suppressed, and amplitude-modulating the signal having a complete passband with a video carrier, obtaining a first signal. The signal whose sideband is equal to the band to be suppressed is phase-shifted by 90.degree. and modulated with the video carrier phase-shifted by 90.degree., obtaining a second signal. The algebraic sum of the first signal and of the second signal obtains a third signal that represents the television signal having the desired side band.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: October 13, 1998
    Assignee: M.B. International S.r.l.
    Inventor: Michele Bargauan
  • Patent number: 5815218
    Abstract: A circuit device provided in a video signal processing apparatus. The circuit device includes a tuner for tuning a television signal, an IF amplifier for demodulating the television signal, and an RF converter having an RF oscillator for modulating video and audio signals into a television signal in a VHF band. The tuner, IF amplifier and RF converter are accommodated in a shield case. Further, the circuit device includes a circuit including a resonance circuit having a coil and a capacitor for controlling an oscillation frequency of the RF oscillator and a switch for switching a parameter of the resonance circuit to vary the oscillation frequency.
    Type: Grant
    Filed: January 4, 1996
    Date of Patent: September 29, 1998
    Assignee: Funai Electric., Ltd
    Inventor: Osamu Maeda
  • Patent number: 5812221
    Abstract: A UHF transmitter for digital TV signals includes, for example, twelve silicon carbide transistor RF output power amplifier panels driven in parallel by two silicon carbide amplifier driver panels and where each panel is comprised of two modules each further including a 180.degree. signal splitter, a pair of quadraphase signal splitters and combiners, a 180.degree. signal combiner, and five RF amplifier pallets which themselves are comprised of two silicon carbide transistors located on a common flange and operated in push-pull relationship so as to suppress even order distortion products and reduce sensitivity to ground currents. A monitoring system, including a touch screen control display and control panel senses the status of all assemblies so as to allow an operator to control the transmitter and inquire about the status of the various components and power supplies, and to replace one or more units as required without the need for turning the transmitter off.
    Type: Grant
    Filed: February 14, 1997
    Date of Patent: September 22, 1998
    Assignee: Northrop Grumman Corporation
    Inventors: Carlton Daniel Davis, Robert Kent Long, Jack Jerome Hawkins
  • Patent number: 5805240
    Abstract: A radio frequency transmitter includes a video signal input terminal, an audio signal input terminal, a variable frequency modulation degree circuit, a band pass filter, a sound intensity regulation circuit, a voltage controlled oscillator, a modulation mixer, and an amplifying circuit. The transmitter is arranged to eliminate high frequency abnormalities, prevent interference of audio signals with video signals, stabilize the audio frequency response of the transmitter, and improve circuit stability.
    Type: Grant
    Filed: December 27, 1995
    Date of Patent: September 8, 1998
    Assignee: Forward Electronics Co., Ltd.
    Inventors: Yee-Cheng Lo, Venson Liaw
  • Patent number: 5801595
    Abstract: A digital signal processing device and method for vestigial sideband (VSB) modulation of a digital signal. A 2.sup.n -ary digital signal d.sub.i is provided to a baseband shaping filter which samples the signal to provide a baseband signal which has real and imaginary portions Re(S.sub.bb (kT)) and Im(S.sub.bb (kT)), where ##EQU1## The VSB signal is provided with perfect sideband suppression without using analog filters. The digital signal processing device and method is characterized by requiring minimal bandwidth in the shaping filter.
    Type: Grant
    Filed: January 10, 1997
    Date of Patent: September 1, 1998
    Assignee: Harris Corporation
    Inventors: Robert C. Davis, Edwin R. Twitchell
  • Patent number: 5748261
    Abstract: A satellite video receiver (12) for providing output signals to a television signal receiver (52) includes apparatus (10, 15, 16, 20, 45, 60, 65, 70) for operator selection of the modulator output channel frequency of the satellite receiver. The operator may select a modulator main channel, or an alternative manufacturer pre-set modulator default channel. In a first recovery mode, the operator may automatically replace an existing modulator channel with a manufacturer pre-set default channel, e.g., if a chosen main channel is forgotten. In another recovery mode, the operator may automatically re-establish a previously selected modulator main channel recalled from memory.
    Type: Grant
    Filed: March 20, 1996
    Date of Patent: May 5, 1998
    Assignee: Thomson Consumer Electronics, Inc.
    Inventor: Michael Anthony Pugel
  • Patent number: 5737025
    Abstract: In the present invention, an ancillary code is added to a composite video signal in its active video portion. The ancillary code may be spread over several frequencies and summed at the output of a decoder to enhance the legibility of the ancillary code at the output of the decoder. Frequency-stepping may be used to add the ancillary code at ones of a plurality of selected frequencies within the bandwidth of the composite video signal. The ancillary code may be hierarchically apportioned between respective uniquely specified sequential segments corresponding to many distribution points of the composite television signal. This hierarchical ancillary code may be frequency-interleaved between harmonics of the horizontal sync frequency of the composite video signal. The ancillary code may be redundantly added above and below the roll-off frequency of a VCR.
    Type: Grant
    Filed: February 28, 1995
    Date of Patent: April 7, 1998
    Assignee: Nielsen Media Research, Inc.
    Inventors: Robert A. Dougherty, David A. Kiewit, Daozheng Lu, Henry B. Wheeler
  • Patent number: 5638135
    Abstract: A digital encoder includes a matrix circuit for synthesizing chrominance signals R-Y and B-Y based on RGB signals sampled at a predetermined sampling frequency which is an integral multiple of a chrominance subcarrier; low-pass filters; a delay circuit; a switch circuit for reducing a frequency of an output from the low-pass filters; a digital modulator for subjecting a chrominance subcarrier to quadrature two-phase balanced modulation using an output signal from the switch circuit so as to output a chrominance signal having a sampling frequency 1/m that of the predetermined sampling frequency; a sampling frequency conversion circuit for multiplying the sampling frequency of the chrominance signal by a factor of m so as to output a chrominance signal having the predetermined sampling frequency; and an adder for computing a sum of the luminance signal delayed by the delay circuit, the chrominance signals output by the sampling frequency conversion circuit and a composite synchronizing signal so as to synthesiz
    Type: Grant
    Filed: April 4, 1996
    Date of Patent: June 10, 1997
    Assignee: Ricoh Company, Ltd.
    Inventor: Takuo Mukai
  • Patent number: 5635995
    Abstract: A dual chrominance signal processor is disclosed which may be used in a combination television and video cassette recorder system, for example. Such a chrominance signal processor includes first and second modulated chrominance signal sources, and first and second demodulating carrier signal sources, corresponding to the first and second modulated chrominance signal sources, respectively. A demodulator is responsive to a chrominance signal and a demodulating carrier signal, for demodulating the chrominance signal. A signal selector is coupled between the signal sources and the demodulator, and selectively couples one of the first and second chrominance signal sources, and the corresponding one of the first and second demodulating carrier signal sources, to the demodulator in response to a selection signal.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: June 3, 1997
    Assignee: David Sarnoff Research Center, Inc.
    Inventors: Christopher H. Strolle, Steven T. Jaffe
  • Patent number: 5596319
    Abstract: A vehicle remote control system includes at least one remote controlled vehicle and a remote control station for each of the at least one remotely controlled vehicles. Each control station allows a user to control the operation of one of the remote control vehicles. Each remote controlled vehicle includes a camera having a lens with a field of view in a direction toward a forward path of travel for that vehicle. In a preferred embodiment, the vehicle is a car and includes various sensors for monitoring the operation of various parameters of the vehicle, such as speed. Each car is equipped with an instrument panel located in the field of view of the lens as well as two side rear view mirrors, one attached to a left fender and the other to a right fender, which are also located in the field of view of the lens.
    Type: Grant
    Filed: October 31, 1994
    Date of Patent: January 21, 1997
    Inventor: Willie L. Spry
  • Patent number: 5585837
    Abstract: A video signal processing and distribution apparatus receives a cable television signal which includes a plurality of television channels. The cable television signal is transferred through one or more band block filters, each of which can block a particular channel from the cable television signal. An oscillator is provided for each local video signal that is desired to be added into the cable television signal. Each oscillator produces a carrier signal within the band of a removed television channel. The local video signal modulates the carrier signal to produce a new channel signal that is combined with the cable signal, which has had at least one selected channel removed. The resulting modified cable signal is distributed to one or more television sets wherein each set can view a plurality of new locally generated channels which have been added to the cable television signal in place of previously existing channels.
    Type: Grant
    Filed: March 15, 1995
    Date of Patent: December 17, 1996
    Inventor: Dale B. Nixon
  • Patent number: 5555275
    Abstract: At the transmitter side of a signal transmission system, carrier waves are modulated according to an input signal for producing relevant signal points in a signal space diagram. The input signal is divided into two, first and second, data streams. The signal points are divided into signal point groups to which data of the first data stream are assigned. Also, data of the second data stream are assigned to the signal points of each signal point group. A difference in the transmission error rate between the first and second data streams is developed by shifting the signal points to other positions in the space diagram. At the receiver side of a signal transmission, the first and/or second data streams can be reconstructed from a received signal. In TV broadcast service, a TV signal is divided by a transmitter into two, low and high, frequency band components which are designated as a first and a second data stream respectively.
    Type: Grant
    Filed: April 5, 1995
    Date of Patent: September 10, 1996
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Mitsuaki Oshima
  • Patent number: 5541671
    Abstract: A satellite video receiver (12) for providing output signals to a television signal receiver (52) includes apparatus (10, 15, 16, 20, 45, 60, 65, 70) for operator selection of the modulator output channel frequency of the satellite receiver. The operator may select a modulator main channel, or an alternative manufacturer pre-set modulator default channel. In a first recovery mode, the operator may automatically replace an existing modulator channel with a manufacturer pre-set default channel, e.g., if a chosen main channel is forgotten. In another recovery mode, the operator may automatically re-establish a previously selected modulator main channel recalled from memory.
    Type: Grant
    Filed: February 6, 1995
    Date of Patent: July 30, 1996
    Assignee: Thomson Consumer Electronics Inc.
    Inventor: Michael A. Pugel