Single Or Vestigial Sideband Type Patents (Class 332/170)
  • Patent number: 10523156
    Abstract: A unit cell for a resistive mixer includes a plurality of active devices arranged in series, wherein each of said plurality of active devices having a different output conductance. A resistive mixer includes a plurality of active devices connected in series with one another to form a unit cell.
    Type: Grant
    Filed: June 29, 2017
    Date of Patent: December 31, 2019
    Assignee: HRL Laboratories, LLC
    Inventors: Jongchan Kang, Ara K. Kurdoghlian
  • Patent number: 8699600
    Abstract: A frequency and data synchronization control system through the 8VSB SFN DTx modulation prevents the deterioration of the digitally broadcasted receiving sensitivity caused by a discrepancy of the frequency or data between the receiver of the digital broadcasting signal and the distributed translator or between distributed translators.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: April 15, 2014
    Assignee: K-Tech Telecommunications, Inc
    Inventor: Steve Kuh
  • Patent number: 8344818
    Abstract: A single sideband mixer is constructed with digital logic elements such as T-type flip-flops and inverters and with FETs, and the resulting mixer circuit simultaneously improves control over the frequency resolution, noise floor and operating frequency range. The use of this group of elements also allows the mixer circuit to be easily realized in an integrated circuit.
    Type: Grant
    Filed: June 15, 2007
    Date of Patent: January 1, 2013
    Assignee: Scientific Components Corporation
    Inventor: Doron Gamliel
  • Patent number: 8242857
    Abstract: A single side band (SSB) mixer includes an in-phase SSB mixer unit and a quadrature-phase SSB mixer unit. The in-phase SSB mixer unit generates an in-phase output current, and includes a first transformer load in which a portion of a quadrature-phase output current flows. The quadrature-phase SSB mixer unit generates the quadrature-phase output current, and includes a second transformer load in which a portion of the in-phase output current flows. The SSB mixer may be used in a wide frequency band without degrading frequency selectivity.
    Type: Grant
    Filed: July 14, 2010
    Date of Patent: August 14, 2012
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Kyung-Goo Moh
  • Publication number: 20110043296
    Abstract: A single side band (SSB) mixer includes an in-phase SSB mixer unit and a quadrature-phase SSB mixer unit. The in-phase SSB mixer unit generates an in-phase output current, and includes a first transformer load in which a portion of a quadrature-phase output current flows. The quadrature-phase SSB mixer unit generates the quadrature-phase output current, and includes a second transformer load in which a portion of the in-phase output current flows. The SSB mixer may be used in a wide frequency band without degrading frequency selectivity.
    Type: Application
    Filed: July 14, 2010
    Publication date: February 24, 2011
    Inventor: Kyung-Goo Moh
  • Patent number: 7826549
    Abstract: A method and apparatus is disclosed herein for transmitting data wirelessly.
    Type: Grant
    Filed: November 2, 2006
    Date of Patent: November 2, 2010
    Inventor: Sudhir Aggarwal
  • Patent number: 7738616
    Abstract: A phase tracking system includes a source of an input signal representing a received symbol. A phase rotator has a first input terminal which is responsive to the input signal, a second input terminal which is responsive to a phase correction signal, and an output terminal which produces a phase adjusted output signal. A decision element generates an ideal signal representing the received symbol in response to the phase adjusted output signal. A phase adjuster, which has full phase wrap-around capability, generates the phase correction signal in response to the phase difference between the phase adjusted output signal and the ideal signal.
    Type: Grant
    Filed: April 16, 2002
    Date of Patent: June 15, 2010
    Assignee: Thomson Licensing
    Inventor: Ivonete Markman
  • Patent number: 7728691
    Abstract: A modulator for radio-frequency signals designed an entirely digital modulator has two mixer stages connected in series. The first mixer stage implements with a relatively low first sample rate a frequency mixing with a first oscillator frequency that is adjustable with high precision. The second mixer stage implements a frequency mixing with a significantly higher second sample rate and with a relatively coarsely adjustable second oscillator frequency. The downstream second mixer stage, in the case of a single mixer stage, the mixer stage, has at least two phase accumulators that are incremented with the higher second sample rate but with different incremental values. The output signal of at maximum one of the phase accumulators is evaluated at any point in time.
    Type: Grant
    Filed: October 15, 2008
    Date of Patent: June 1, 2010
    Assignee: Siemens Aktiengesellschaft
    Inventors: Nikolaus Demharter, Philipp Hoecht, Martin Nisznansky
  • Patent number: 7570127
    Abstract: An IF receiver receives a tapped portion of a modulated communication signal. A processor, local with respect to the IF receiver, receives an interrupt from a main processor instructing it to evaluate the power levels of desired and undesired components of the communication signal. The interrupt may be sent for a variety of reasons, such as according to a predetermined schedule, or in response to changes in a communication network, such as new equipment installation and temperature changes. The local processor instructs the IF receiver to tune it's LO so that the evaluation range of the receiver and feedback loop to parameter-adjustable components includes the frequency, or frequencies, of a specified signal component. The local processor evaluates the power level of the specified signal component. Based on the evaluation, the local processor instructs parameter-adjustable signal processing components to alter parameters to optimize characteristics of the communication signal for transmission.
    Type: Grant
    Filed: November 21, 2007
    Date of Patent: August 4, 2009
    Assignee: ARRIS Group, Inc.
    Inventors: Gerald P. Ryan, Ubaldo Cepeda
  • Publication number: 20090096546
    Abstract: A modulator for radio-frequency signals designed an entirely digital modulator has two mixer stages connected in series. The first mixer stage implements with a relatively low first sample rate a frequency mixing with a first oscillator frequency that is adjustable with high precision. The second mixer stage implements a frequency mixing with a significantly higher second sample rate and with a relatively coarsely adjustable second oscillator frequency. The downstream second mixer stage, in the case of a single mixer stage, the mixer stage, has at least two phase accumulators that are incremented with the higher second sample rate but with different incremental values. The output signal of at maximum one of the phase accumulators is evaluated at any point in time.
    Type: Application
    Filed: October 15, 2008
    Publication date: April 16, 2009
    Inventors: Nikolaus Demharter, Philipp Hoecht, Martin Nisznansky
  • Publication number: 20080116987
    Abstract: An IF receiver receives a tapped portion of a modulated communication signal. A processor, local with respect to the IF receiver, receives an interrupt from a main processor instructing it to evaluate the power levels of desired and undesired components of the communication signal. The interrupt may be sent for a variety of reasons, such as according to a predetermined schedule, or in response to changes in a communication network, such as new equipment installation and temperature changes. The local processor instructs the IF receiver to tone it's LO so that the evaluation range of the receiver and feedback loop to parameter-adjustable components includes the frequency, or frequencies, of a specified signal component. The local processor evaluates the power level of the specified signal component. Based on the evaluation, the local processor instructs parameter-adjustable signal processing components to alter parameters to optimize characteristics of the communication signal for transmission.
    Type: Application
    Filed: November 21, 2007
    Publication date: May 22, 2008
    Inventors: Gerald P. Ryan, Ubaldo Cepeda
  • Patent number: 7016659
    Abstract: In an AM system directed to commercial broadcasting, a pure unmodulated (CW) carrier signal and two sideband signals are generated and processed separately as three independent signals that are summed as output of a final linear mixer. The sideband signals are derived independently utilizing audio spectrum-sharing based on complementary comb filtering, quadrature phase-shifting at both audio and carrier sideband frequencies, and exclusive alternate toggling at a designated switching rate between the two sidebands so that at any instant in time only one of the two sidebands is present along with the continuous carrier. The overall performance provides the capability of advantageous modulation beyond the conventional 100% modulation limit.
    Type: Grant
    Filed: June 12, 2003
    Date of Patent: March 21, 2006
    Inventors: Michael L. Dorrough, Dennis Robert Lee, Alfred Edward Parker, Richard Williamson Burden
  • Patent number: 6850575
    Abstract: The present invention relates to a single side band modulator for splitting a signal into a first split signal and a second split signal 90 degrees out of phase with the first split signal. A first double balanced mixer modulates the first split signal and includes a transformer, a modulating signal input, and a first diode ring. The transformer connects the first diode ring to a quadrature hybrid. A second double balanced mixer modulates the second split signal and includes a transformer, a modulating signal input, and a second diode ring. The transformer of the second double balanced mixer connects the second diode ring to the quadrature hybrid. The first and second diode rings are connected in parallel and are connected to a third transformer which performs the function of a power combiner.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: February 1, 2005
    Assignee: Synergy Microwave Corporation
    Inventor: Vaseem Ahmed
  • Patent number: 6731757
    Abstract: A method of and apparatus for digitally generating a broadband signal comprising a plurality of CW or quadrature modulated signals having incrementally related frequencies wherein said plurality of signals are centered about a center RF frequency is disclosed. The invention provides for generating a first and second composite baseband signal each comprising a linear combination of N sinusoids, or N modulated signals each modulated in quadrature so as to achieve a desired instantaneous phasor value for each of the RF signals. The invention further provides for modulating in quadrature the first and second composite baseband signals on a local oscillator signal having a frequency equal to the center RF frequency.
    Type: Grant
    Filed: November 14, 2000
    Date of Patent: May 4, 2004
    Assignee: Broadband Innovations, Inc.
    Inventor: Ron D. Katznelson
  • Patent number: 6720839
    Abstract: A system of and method for reducing or eliminating any unwanted sideband component in a signal derived from the output of a quadrature modulator. An unwanted sideband detector detects the unwanted sideband in the output of the quadrature modulator, and responsive thereto, a correction circuit corrects a baseband signal prior to inputting it to the quadrature modulator. In one embodiment, the unwanted sideband detector is an envelope detector.
    Type: Grant
    Filed: February 29, 2000
    Date of Patent: April 13, 2004
    Assignee: Skyworks Solutions, Inc.
    Inventors: Valentina Della Torre, Frederic M. Stubbe, Morten Damgaard, Ricke W. Clark
  • Patent number: 6647074
    Abstract: Circuits for removing clock related artifacts in an offset QAM generated VSB signal includes a transmitter arrangement and a receiver arrangement. In the transmitter, a detector detects the artifacts and a correlator determines whether the artifacts repeat over two symbols or over four symbols. A signal indicative of the artifacts is used to control processing circuits for adjusting the ratios and levels of the I and Q signal components of the QAM signal for substantially eliminating the artifacts. In the receiver, the received VSB signal is divided into four parallel signals. Each parallel signal is processed to develop an average symbol level that is subtracted before the parallel signals are recombined. The four symbol repeat rate artifacts reflect a DC offset of the VSB signal symbols, which are both positive-going and negative-going and which therefore average to zero for random signals. Averaging is done over N symbols where N is a power of 2.
    Type: Grant
    Filed: October 18, 2001
    Date of Patent: November 11, 2003
    Assignee: Zenith Electronics Corporation
    Inventors: Richard W. Citta, Larry E. Nielsen
  • Patent number: 6618096
    Abstract: A digital signal processing vestigial-sideband television modulator receives a television signal. The present invention digitizes the television signal to generate a video signal and a digital processor processes the video signal to generate a complex baseband signal. The complex baseband signal is converted into an in-phase baseband signal and a quadrature baseband signal and modulated to respectively generate a modulated in-phase baseband signal and a modulated quadrature baseband signal. The modulated in-phase baseband signal and the modulated quadrature baseband signal are combined to produce a vestigial radio frequency television signal. The undesired sideband of the vestigial radio frequency television signal is tapped, filtered, and, subsequently, the power level of the undesired sideband is detected. Any imbalance in the modulation process is compensated by using the detected power level of the undesired sideband.
    Type: Grant
    Filed: September 29, 1997
    Date of Patent: September 9, 2003
    Assignee: Scientific-Atlanta, Inc.
    Inventor: Shawn Stapleton
  • Patent number: 6606010
    Abstract: A quadrature vestigial sideband (QVSB) communication system provide bandwidth efficient data transmission using cross coupled data signaling during both transmit and receive having controlled intersymbol interference. The QVSB modem includes cross coupled arm transmit and receive data filtering on both of the I&Q channels providing a bandwidth efficient QVSB spectra. A quadrature crosstalk maximum likelihood sequence estimator implements a Viterbi decoding algorithm for providing estimated data sequence outputs. The receiver is a coherently aided demodulator synchronized by a synchronization loop providing time and phase references using the estimated data sequence outputs.
    Type: Grant
    Filed: January 30, 2002
    Date of Patent: August 12, 2003
    Assignee: The Aerospace Corporation
    Inventors: John J. Poklemba, Gregory S. Mitchell
  • Patent number: 6567394
    Abstract: An IC card, an IC card processor, and an IC card system are simply arranged to perform full-duplex data exchange efficiently using a frequency band in such a manner that a transmission signal sent from the IC card processor is received by an antenna, the transmission signal is demodulated, and a response signal to be sent from the antenna is formed by modulating a main carrier having the same frequency as a main carrier of the transmission signal with a response data sequence in such a manner that a sideband of the response signal does not overlap a sideband of the transmission signal along the frequency axis.
    Type: Grant
    Filed: February 4, 1999
    Date of Patent: May 20, 2003
    Assignee: Sony Corporation
    Inventor: Shigeru Arisawa
  • Patent number: 6531935
    Abstract: An analogue phase shifter with vector modulator is envisioned. The analogue phase shifter has an input stage that provides the generation of a pseudo-basis of four vectors. The analogue phase shifter has a multiphase filter. The analogue phase shifter has an output stage that controls the amplitde of the basis vectors, and acts to recombine them. The input stase is made with a phase opposition signal generator and a multiphase filter. The input stase is made of four variable attenuators. The attenuators are for separate control of the amplitude of each of the basis vectors. The output stage also has a common output providing the summation of four quadrature channels. In one case, the output stage includes two differential amplifiers. In another case the quadrature channels are connected to the common output through buffer amplifier stages, each followed by a summation capacitor.
    Type: Grant
    Filed: March 5, 2001
    Date of Patent: March 11, 2003
    Assignee: Commissariat a l'Energie Atomique
    Inventors: Jean Russat, Nicolas Fel
  • Patent number: 6532270
    Abstract: In the broadcast band having a plurality of channels allocated therein, by using high-side injection and low-side injection as described herein, the noise introduced into the channel by the local oscillator signal can be minimized. The local oscillator signal in combination with the intermediate frequency determines the frequency of the channel signal being produced by the transmitter. The selected high-or low-side injection determines whether the bulk of the power is introduced into the combination frequency signal (i.e., the channel) above or below the local oscillator frequency, thereby moving the local oscillator frequency outside the broadcast band. The non-selected sideband is even further outside broadcast band.
    Type: Grant
    Filed: December 16, 1998
    Date of Patent: March 11, 2003
    Assignee: Legerity, Inc.
    Inventors: Eddy Kent Bell, Javier V. MagaƱa, Stephen T. Janesch
  • Patent number: 6522213
    Abstract: In an SSB transmitter, a problem such that the central frequency of a BPF for extracting one of sideband signals from the modulated signals obtained by modulating a carrier frequency signal by an input sound signal is changed by temperatures, causing a drop in suppression ration and a deterioration in sound is solved. The microcomputer circuit 23 determines the change of the central frequency (−&Dgr;&agr;) of the BPF 5 from the compensation table related to the BPF 5 stored in the ROM 32 based on a temperature information of the BPF 5 detected by the temperature sensor 21; controls local oscillators 4a and 7a that output modulated signals and VHF band signals to the balanced modulator 3 and the mixer 6; and changes the frequency of each signal by −&Dgr;&agr; from the standard condition.
    Type: Grant
    Filed: October 4, 2001
    Date of Patent: February 18, 2003
    Assignee: Vertex Standard Co., Ltd.
    Inventor: Yoshiteru Hashimoto
  • Patent number: 6496545
    Abstract: In accordance with the invention, a single sideband mixer includes first and second all-pass 90° phase shifters. Each phase shifter produces two outputs of substantially equal amplitude but subject to a phase angle error (&thgr;) indicative of a deviation from quadrature of the two outputs. The phase angle errors of the first and second phase shifters are designed to be equal and to track each other over different ambient and operating voltage conditions. In one embodiment, the outputs of the first phase shifter are coupled via a cross switch to the inputs of two mixers and the outputs of the second phase shifter are fixedly connected to the inputs of the two mixers. The outputs of the two mixers are combined to produce an output whose frequency is a function of either the sum or the difference of first and second input frequency signals respectively applied to the first and second phase shifters.
    Type: Grant
    Filed: February 2, 1999
    Date of Patent: December 17, 2002
    Assignee: Lucent Technologies Inc.
    Inventor: Ting-Ping Liu
  • Publication number: 20020063606
    Abstract: An image reject circuit comprises a local oscillator 26 for producing a local oscillator signal. A tunable phase shifting network 29 has inputs 1, 3 for receiving the local oscillator signal and producing an output in-phase (I) signal 13, 25 and an output quadrature (Q) signal 15, 27. A first amplitude detector 33 determines the amplitude of the output I signal, while a second amplitude detector 35 determines the amplitude of the output Q signal. A comparator 37 determines the difference between the amplitudes of the output I and Q signals, to produce a tuning signal for tuning the phase shifting network 29 to bring the difference between the amplitudes of the output I and Q signals towards a desired level. Preferably, the tunable phase shifting network 29 (shown in FIG. 4) comprises a combination of tunable capacitive, resistive and inductive elements.
    Type: Application
    Filed: December 5, 2000
    Publication date: May 30, 2002
    Applicant: Telefonaktiebolaget L M Ericsson
    Inventor: Paulus Thomas Maria van Zeijl
  • Publication number: 20020044024
    Abstract: In an SSB transmitter, a problem such that the central frequency of a BPF for extracting one of sideband signals from the modulated signals obtained by modulating a carrier frequency signal by an input sound signal is changed by temperatures, causing a drop in suppression ration and a deterioration in sound is solved.
    Type: Application
    Filed: October 4, 2001
    Publication date: April 18, 2002
    Applicant: VERTEX STANDARD CO., LTD
    Inventor: Yoshiteru Hashimoto
  • Patent number: 6351500
    Abstract: A method and system are provided for the transmission and reception of a composite radio-frequency (RF) signal including a supplemental signal, preferably representing encoded digital information, together with an analog signal which represents monophonic analog audio in the AM-band. The analog monophonic component of the composite signal may be received by conventional AM-band audio receivers. In certain embodiments, the analog signal is a single-sideband large-carrier or vestigial-sideband large-carrier signal, and the composite RF signal includes a digital signal whose spectrum is substantially confined in one inner sideband. In other embodiments, a baseband digital signal is combined with an analog monophonic audio signal and transmitted in upper inner and lower inner sidebands using nonlinear compatible quadrature amplitude modulation (NC-QAM). Additional digital signals' spectrum occupies the lower outer and upper outer sidebands.
    Type: Grant
    Filed: December 20, 1999
    Date of Patent: February 26, 2002
    Assignee: Digital Radio Express, Inc.
    Inventor: Derek D. Kumar
  • Patent number: 6148320
    Abstract: A multichannel television access control system is disclosed wherein processing of the broadband signal is performed by gated coherent RF injection on a plurality of channels, thereby effecting selective descrambling of an arbitrary subset of channels in a channel group. The system provides for a closed loop injection signal phasor control so as to maintain substantially constant relationship between the television signals and the injected signals. The combined signals are supplied to subscribers enabling the use of their cable ready equipment.
    Type: Grant
    Filed: May 18, 1998
    Date of Patent: November 14, 2000
    Inventor: Ron D. Katznelson
  • Patent number: 6091303
    Abstract: A circuit for reducing phase noise in a transmitted radio signal includes a first phase-locked loop circuit including a first controlled oscillator generating a first output signal at a first desired frequency, and a first phase comparator developing a first phase error signal to control the first controlled oscillator, the first error signal representative of phase differences between the first output signal and the first desired frequency. A second phase-locked loop circuit includes a second controlled oscillator generating a second output signal at a desired frequency of transmission related to the first desired frequency, and a second phase comparator developing a second phase error signal representative of phase differences between the first output signal and the desired frequency of transmission.
    Type: Grant
    Filed: April 6, 1999
    Date of Patent: July 18, 2000
    Assignee: Ericsson Inc.
    Inventor: Paul W. Dent
  • Patent number: 6005894
    Abstract: A method and system are provided for the transmission and reception of a composite radio-frequency (RF) signal including a supplemental signal, preferably representing encoded digital information, together with an analog signal which represents monophonic analog audio in the AM-band. The analog monophonic component of the composite signal may be received by conventional AM-band audio receivers. In certain embodiments, the analog signal is a single-sideband large-carrier or vestigial-sideband large-carrier signal, and the composite RF signal includes a digital signal whose spectrum is substantially confined in one inner sideband. In other embodiments, a baseband digital signal is combined with an analog monophonic audio signal and transmitted in upper inner and lower inner sidebands using nonlinear compatible quadrature amplitude modulation (NC-QAM). Additional digital signals' spectrum occupies the lower outer and upper outer sidebands.
    Type: Grant
    Filed: April 4, 1997
    Date of Patent: December 21, 1999
    Inventor: Derek D. Kumar
  • Patent number: 5861781
    Abstract: A method of and apparatus for effecting single sideband modulation which mixes and sums the quadrature and in-phase components of a baseband signal with the in-phase and quadrature components of an intermediate frequency (IF) signal to form in-phase and quadrature components of a sum signal having a frequency equal to the sum of the frequencies of the baseband and intermediate frequency signals and which mixes and sums the quadrature and in-phase components of an RF carrier signal with the in-phase and quadrature components of the sum signal to form a single-sideband signal.
    Type: Grant
    Filed: September 16, 1997
    Date of Patent: January 19, 1999
    Assignee: Lucent Technologies Inc.
    Inventor: Kirk Burton Ashby
  • Patent number: 5822685
    Abstract: A modulating reflector circuit arrangement comprising a transistor configured by means of a feedback arrangement upon operation within a linear region of the transistor's current/voltage characteristic to reflect an incoming amplitude modulated signal with an increased amplitude and a modulator operable to modulate power to the transistor with a periodic waveform in which the reciprocal of the period of the periodic waveform is the required sideband frequency of the reflected signal and the waveform is selected such that the arrangement reflects a substantially single sideband signal.
    Type: Grant
    Filed: June 26, 1996
    Date of Patent: October 13, 1998
    Assignee: GEC Marconi, Limited
    Inventor: Ian J. Forster
  • Patent number: 5815532
    Abstract: A method and apparatus for reducing peak-to-average power ratio in a paging transmitter broadcasting an independent sideband amplitude modulation protocol is disclosed. A digital signal, for example a digital voice signal, is provided to a control gain generator which generates a digital gain sequence. The digital gain sequence is such that during peak values in the digital signal the gain is low and during low values in the digital signal the gain is high. The digital gain sequence is multiplied with the digital signal to compress the dynamic range of the digital signal.
    Type: Grant
    Filed: May 1, 1996
    Date of Patent: September 29, 1998
    Assignee: Glenayre Electronics, Inc.
    Inventors: Bhaskar Bhattacharya, Patricia Fern Kavanagh, Mohammad Aamir Husain
  • 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: 5764701
    Abstract: A VSB modulator receives a stream of data at a 10.76 MHz constant symbol rate and converts it to a 6 MHz bandwidth signal centered at 44.0 MHz. The incoming data is interpolated by three to generate three data images and a digital filter selects the image embracing the range of 5.38 to 10.76 MHz. A sine X/X correction is added to compensate for the loss experienced in the D/A converter. The signal for the D/A converter is filtered and mixed with a 35.93 MHz oscillator output to produce data about the 44.0 MHz IF frequency. A SAW filter rejects all but the desired data.
    Type: Grant
    Filed: March 4, 1996
    Date of Patent: June 9, 1998
    Assignee: Zenith Electronics Corporation
    Inventor: Thomas P. Horwitz
  • Patent number: 5745273
    Abstract: A single sideband modulator circuit for modulating an optical signal with an RF signal to provide a frequency shift to the optical signal. The modulator circuit utilizes a dual path modulator having an electrical terminal and two optical terminals. An RF signal is provided to the electrical terminal and an optical signal is provided to each optical terminal so that the optical signal input to one terminal travels in the direction of the RF signal to produce an output optical signal having a carrier band and a single sideband, and the optical signal input to the other optical terminal travels in the opposite direction of the RF signal to produce an output having only a carrier band. A coupler adds the resulting optical output signals so that the carrier bands are cancelled, leaving only the sideband.
    Type: Grant
    Filed: November 27, 1996
    Date of Patent: April 28, 1998
    Assignee: Lucent Technologies Inc.
    Inventor: Robert Meachem Jopson
  • Patent number: 5631610
    Abstract: A communication system having a modulation system for transmitting a symbol set via a single side-band modulated carrier and a demodulation system for recovering the in-phase and quadrature signals from the modulated carrier. The modulation circuit receives M symbol values and generates M time domain samples for each of the in-phase and quadrature signals. The in-phase and quadrature signals can then be combined to generate the single side-band modulated carrier. The modulation circuit includes a transform circuit for generating M transformed symbol values by computing the transform of the M symbol values. A polyphase filter bank having 2M FIR filters is used to process the output of the transform circuit. Each filter has g taps, where g is an integer greater than 1. The outputs of the polyphase filters are combined with the outputs of the polyphase filters generated from a previously received set of M symbols to generate the M time-domain signal values of the in-phase signal.
    Type: Grant
    Filed: January 25, 1996
    Date of Patent: May 20, 1997
    Assignee: Aware, Inc.
    Inventors: Stuart Sandberg, Michael Tzannes
  • Patent number: 5506548
    Abstract: A Single-Sideband (SSB) modulator includes:a demultiplexer for successively distributing an A/D converted digital signal x(t) to L sequences x.sub.1 (t.sub.1), x.sub.2 (t.sub.2)... ...x.sub.L (t.sub.L) in accordance with a sampling period t, an adder including L/2 adders for adding constants to x.sub.i (t.sub.i) of the demultiplexer, where i is either an even or an odd number; a phase shift network system comprising L/2 phase shift networks for making a 90-degree phase difference between the outputs of the adder and x.sub.i (t.sub.i) of the demultiplexer; a timing signal generator for generating timing signals expressed by A(-1).sup.(KL)/2+n and/or A(-1).sup.((K-1)L)/2+n in accordance with the sampling period t; a multiplier including L/2 pair of multipliers for multiplying the outputs of the phase shift network system by the outputs of the timing signal generator; a multiplexer for selecting the outputs of the multiplier in accordance with the sampling period t.
    Type: Grant
    Filed: September 28, 1994
    Date of Patent: April 9, 1996
    Assignee: Icom Incorporated
    Inventors: Shigeki Kajimoto, Weimin Sun
  • Patent number: 5469127
    Abstract: The present invention provides a system and method in which an arbitrary information-modulated signal is efficiently amplified to high power levels. The arbitrary information-modulated signal is received at a low power level and is separated into elemental signals. In a preferred embodiment, a frequency/phase information signal and an amplitude information signal are the elemental signals which collectively represent the essential information in the original information-modulated signal. The circuit uses the elemental signals to provide an amplified replica of the original information-modulated signal. The amplification preferably, though not necessarily, involves using the digital amplitude modulators disclosed in U.S. Pat. No. 4,804,931, U.S. Pat. No. 5,260,674, or U.S. Pat. No. 5,367,272.
    Type: Grant
    Filed: June 7, 1994
    Date of Patent: November 21, 1995
    Assignee: Acrodyne Industries, Inc.
    Inventors: Timothy P. Hulick, Julian L. Brookes
  • Patent number: 5450044
    Abstract: The invention provides various embodiments of a balanced modulator, each of which involves one or more individual amplitude modulators which, individually, do not provide suppressed-carrier outputs. A first embodiment employs a single amplitude modulator whose carrier input is selectively delayed by a half wavelength, depending on the polarity of the input modulating signal, and whose amplitude input receives the absolute value of the modulating input signal. A second embodiment involves summation of the outputs of two amplitude modulators whose carrier inputs are responsive to carrier signals offset by a half carrier wavelength and whose modulating signal inputs are responsive only to signals of respectively opposite polarity. Further, quadrature amplitude modulation (QAM) modulators are provided by a combination of the above-described modulators.
    Type: Grant
    Filed: April 14, 1993
    Date of Patent: September 12, 1995
    Assignee: Acrodyne Industries, Inc.
    Inventor: Timothy P. Hulick
  • Patent number: 5446423
    Abstract: A digital single sideband modulator (10) includes a relatively complex CMOS NCO (14) that drives a relatively simple ECL frequency translator (30). The frequency translator (30) outputs a digital signal that is converted to analog by a D/A (44) and then filtered in a bandpass filter (46) having a pass band including a frequency of twice the NCO's clock frequency. The NCO (14) generates a modulated intermediate frequency NCO signal having quadrature components. The frequency translator (30) multiplies real and imaginary components of the NCO signal by real and imaginary components of digitized SIN, COS sampling functions (48, 50). The resulting products are added together. The adding operation is performed by a multiplexer (32), whose selection input is driven at twice the carrier frequency, and the multiplying operations are performed by a selective negation circuit (34), that is driven at the carrier frequency.
    Type: Grant
    Filed: September 19, 1994
    Date of Patent: August 29, 1995
    Assignee: Motorola, Inc.
    Inventors: Richard A. Bienz, Lansing M. Carson, Marty K. Siemon
  • Patent number: 5436600
    Abstract: A local frequency generator employing a single crystal oscillator, latches and direct digital synthesizer circuits digitally produces all signals needed in the transmitter channel of a MRI system to generate MRI transmitter RF pulses. The local frequency generator is operable in both the single side band and double side band modes and has the capability of switching between the modes. The generator is constructed with a phase resetting capability for providing the plural output frequencies needed for making plural MRI slices.
    Type: Grant
    Filed: July 29, 1994
    Date of Patent: July 25, 1995
    Assignee: The Regents of the University of California
    Inventors: John Van Heteren, Mitsuaki Arakawa, Lawrence E. Crooks, John C. Hoenninger, III, Thomas McDermott, Keiji Furui
  • Patent number: 5416449
    Abstract: An improved modulator circuit for mixing a modulation signal with a carrier signal includes first and second harmonic mixers which are operative to produce modulated output signals at an output frequency corresponding to both the sum and the difference of the modulation signal frequency and the even harmonic frequencies of the carrier signal frequency. In one configuration employing a 90.degree. hybrid, the output signals of the harmonic mixers are combined to produce a single sideband modulated output signal. A novel harmonic mixer circuit is also provided along with demodulator circuits and methods of modulating and demodulating modulation signals.
    Type: Grant
    Filed: May 23, 1994
    Date of Patent: May 16, 1995
    Assignee: Synergy Microwave Corporation
    Inventor: Shankar R. Joshi
  • Patent number: 5394118
    Abstract: A digital circuit having a first section for converting a low-frequency signal into a sampled single sideband signal, coupled to a second section for separating the sampled SSB signal into its two components, the phase and envelope components.
    Type: Grant
    Filed: November 16, 1993
    Date of Patent: February 28, 1995
    Assignee: Thomson-CSF
    Inventors: Bernard Darges, Jean-Francois Helm, deceased, by Veronique Helm wife Gauthier, legal representative
  • Patent number: 5373265
    Abstract: Apparatus and method for effecting single sideband suppressed carrier modulation suitable for small, hand-held, high-frequency cellular radio transmitters such as those used at 900 mHz. A local oscillator generates a signal at 0.8 the frequency of the desired carrier. The generated frequency is counted down to produce an IF that is 0.2 the frequency of the desired carrier and the IF is mixed with the baseband signal to produce a modulated IF. The modulated IF is then mixed with the first generated signal to generate the modulated carrier signal. Advantageously, all of the foregoing components can be provided on the same integrated circuit chip.
    Type: Grant
    Filed: July 6, 1993
    Date of Patent: December 13, 1994
    Assignee: AT&T Corp.
    Inventors: Paul C. Davis, Irving G. Post
  • Patent number: 5327462
    Abstract: In this invention, in order to generate a VSB modulation signal from a digital baseband signal, an in-phase component of a modulation signal having a frequency spectrum having a high-frequency component whose level is half that of its low-frequency component, and an orthogonal component of the modulation signal of a high-frequency component having a frequency spectrum whose level is half that of the low-frequency component are generated from the baseband signal. The in-phase component and the orthogonal component are multiplied with carrier signals to obtain a carrier in-phase component and a carrier orthogonal component. The carrier in-phase component and the carrier orthogonal component are synthesized to obtain a VSB modulation signal.
    Type: Grant
    Filed: February 7, 1992
    Date of Patent: July 5, 1994
    Assignees: Kabushiki Kaisha Toshiba, Nippon Hoso Kyokai
    Inventors: Yasuo Takahashi, Tatsuya Ishikawa, Toshio Aoki, Nobuyuki Miki, Masatoshi Hamada, Masatoshi Hamada, Yasuhiro Hashimoto, Kenji Ueoka, Nobuhiko Kawai
  • Patent number: 5243304
    Abstract: In a vestigial sideband modulator, an i.f. signal is modulated with a video input and the extreme part of one of the sidebands is removed to provide the right frequency response shape for transmission. The signal for transmission is usually produced by mixing the i.f. signal with an oscillator signal known as the heterodyne signal which differs from the desired carrier frequency by the i.f. frequency, and filtering the signal with a subsequent channel filter to remove any unwanted heterodyne oscillator components and the unwanted sum or difference product. To avoid the need for such a channel filter, the filtered video-modulated i.f. signal is demodulated to quadrature baseband components using the i.f. oscillator, and quadrature components at carrier frequency are modulated with these baseband components to produce on combination a v.s.b. modulated video output at carrier frequency.
    Type: Grant
    Filed: April 7, 1992
    Date of Patent: September 7, 1993
    Assignee: GEC - Marconi Limited
    Inventor: Alan R. Rixon
  • Patent number: 5222250
    Abstract: A single sideband radio system. The system comprises a transmitter and a receiver. The transmitter comprises a transmitter baseband processing portion for generating a first baseband signal comprising first, second, and pilot components and modulating the first baseband signal in inverse proportion to the strength of the first component of the first baseband signal and an RF output stage for generating and transmitting a single sideband signal comprising first, second, and pilot portions corresponding to the first, second, and pilot components of the modulated first baseband signal. The receiver comprises an RF input stage for receiving the single sideband signal and a receiver baseband processing portion for generating a second baseband signal comprising first, second, and third components corresponding to the first, second, and third portions of the single sideband signal and for correcting the second baseband signal based on the pilot component of the second baseband signal.
    Type: Grant
    Filed: April 3, 1992
    Date of Patent: June 22, 1993
    Inventors: John F. Cleveland, Jay M. Fassett, Mark D. Peterson
  • Patent number: 5162763
    Abstract: A single sideband modulator provides a means of translating low frequency baseband signals directly to radio frequency in a single stage. Such modulators, providing suppressed carrier and one or two of the sidebands, facilitates the transmission of intelligence with significantly increased gain over AM transmission. Control signals are continuously generated to keep the local oscillator breakthrough and image sidebands down to an insignificantly low level. This is achieved by monitoring amplitude of the RF output of the single sideband modulator, and comparing this with the baseband signals. By adjusting the d.c. offsets at the baseband inputs to the balanced modulators, carrier breakthrough is cancelled. By adjusting the relative phases of the baseband signals, deviations from the 90.degree. split are compensated. By changing the amplitude of one of the baseband signals, the level of one of the RF paths is adjusted to achieve amplitude balance.
    Type: Grant
    Filed: November 18, 1991
    Date of Patent: November 10, 1992
    Inventor: Keith D. Morris
  • Patent number: 5159613
    Abstract: An upper and lower side-band generator comprised of a combination of combinational logic circuits. In a preferred embodiment the invention utilizes a substantially square wave sync output associated with carrier and modulator signal generators. A lower side-band signal is generated by synchronizing the transitions of a modulator signal with the transitions of a carrier signal, mixing the synchronized signal with the carrier signal, and filtering the resulting mixed signal. An upper side band signal is generated by synchronizing the carrier and modulator signals, delaying the resulting synchronized signal, and mixing the delayed, synchronized signal and the carrier signal.
    Type: Grant
    Filed: April 2, 1990
    Date of Patent: October 27, 1992
    Assignee: William Beaumont Hospital
    Inventors: Donovan M. Bakalyar, Yong-Sung Paek
  • Patent number: 5077542
    Abstract: A system of transmission with amplitude modulation for the transmission of signals of all types, analog and/or digital, requiring high performance characteristics with respect to the noise induced by the transmission channel, comprising, at transmission, means for the suppressed carrier amplitude modulation of a useful signal and means for the amplitude modulation, in phase quadrature with said modulated useful signal, of a service signal, making it possible, at reception, to remove the ambiguity on the polarity of the demodulated useful signal. Thus it enables the transmission of signals in suppressed carrier modulation mode, hence with a good signal-to-noise ratio, without losing the polarity of the signal. The transmitters and receivers according to the invention also enable the transmission and reception of the signals modulated in SCAM, VSBAM or VSBSCAM modes.
    Type: Grant
    Filed: December 7, 1990
    Date of Patent: December 31, 1991
    Assignees: L'Etat Francais (CNET), Telediffusion de France S. A.
    Inventor: Marc Lanoiselee