Patents Examined by Forester W. Isen
  • Patent number: 6813352
    Abstract: An echo canceler has its otherwise conventional tapped delay line basis functions augmented with at least one pair of basis functions realizing two quadrature responses of a complex pole. The frequency of this complex pole is selected as substantially equal to the frequency of the dominant pole of a highpass filter inserted into the echo path of the echo canceler, where the dominant pole is the pole closest to the unit circle. This echo canceler arrangement results in a substantial improvement in attainable echo-return-loss enhancement (ERLE).
    Type: Grant
    Filed: September 10, 1999
    Date of Patent: November 2, 2004
    Assignee: Lucent Technologies Inc.
    Inventor: Donald Lars Duttweiler
  • Patent number: 6813359
    Abstract: A method and apparatus for minimizing multipath interference for commercial FM signals which use SCA secondary signals in QAM format that includes tracking the time series of phase measurements of a received stereo pilot signal for determining the proper phase reference for demodulation of QAM signals at the center of the time series. Phase measurements of the pilot signal are tracked over a predetermined tracking period. The phase measurement is used to support demodulation of the QAM signal. The SCA secondary signals in QAM format transmitted on commercial FM have minimal multipath interference and Doppler interference by movement of transmitter and receiver (vehicular).
    Type: Grant
    Filed: April 29, 2002
    Date of Patent: November 2, 2004
    Assignee: Bae Systems Information and Electronic Systems Integration Inc.
    Inventor: David L. Herrick
  • Patent number: 6807280
    Abstract: An audio signal processing circuit reduces noise in an incoming audio signal and is particularly useful in telephone communication systems utilizing one or more hands-free microphones. A preferred embodiment of the audio signal processing circuit includes a pre-emphasis circuit receiving the audio signal from a microphone or other transducer, an amplifier circuit receiving the pre-emphasized audio signal from the pre-emphasis circuit and a de-emphasis circuit receiving the amplified signal from the amplifier circuit. An output of the de-emphasis circuit provides the processed audio signal having an improved signal to noise ratio with minimum audible distortion. A preferred embodiment of the amplification circuit includes an amplifier defining a non-linear transfer function therethrough which provides low gain to the lower amplitude noise signals and higher gain to the higher amplitude audio signals.
    Type: Grant
    Filed: January 26, 1998
    Date of Patent: October 19, 2004
    Assignee: Delphi Technologies, Inc.
    Inventors: Richard Sidney Stroud, Gary Michael McQuilling
  • Patent number: 6804350
    Abstract: A method and system for improving performance of an echo canceller with low additional complexity. Specifically, the present invention discloses using information from internal variables of Code Excited Linear Prediction (CELP) based codecs in a digital communication network to significantly improve the rate of convergence of the echo canceller. In one embodiment of the present invention, an error signal associated with a voice signal is filtered by a transversal filter using Linear Predictive Coefficients (LPC) coefficients to provide filter transfer functions for a Filtered-X Least Mean Squares algorithm. Additionally, an adaptive filter applies the Filtered-X Least Mean Squares algorithm using the pre-filtered voice signal available in a CELP-based decoder to create a synthetic echo signal which is subtracted from the echo signal for attenuation.
    Type: Grant
    Filed: December 21, 2000
    Date of Patent: October 12, 2004
    Assignee: Cisco Technology, Inc.
    Inventor: Marcio Siqueira
  • Patent number: 6804352
    Abstract: A telecommunications device including a chassis having a card housing for containing a plurality of splitter cards. The card housing includes front and back ends. The front end of the card housing defines an access opening for allowing the splitter cards to be inserted into or removed from the card housing. The device also includes a plurality of card edge connectors for providing electrical connections with the splitter cards. The card edge connectors are located within the card housing adjacent to the back end of the housing. Each card edge connector is arranged in a generally horizontal orientation. The device further includes forwardly facing LINE, POTS and DATA connectors that are electrically connected to the card edge connectors. At least the LINE and POTS connectors are positioned in a generally horizontal orientation.
    Type: Grant
    Filed: June 29, 2001
    Date of Patent: October 12, 2004
    Assignee: ADC Telecommunications, Inc.
    Inventors: Jennifer L. Miller, Paul W. Schmokel
  • Patent number: 6804353
    Abstract: A telecommunications device including a plurality of splitter cards mounted in a chassis, a circuit board, and plurality of card edge connectors for providing electrical connections between the splitter cards and the circuit board, and POTS, LINE, and DATA connectors. The circuit board includes three layers, each layer having tracings that electrically connect at least one POTS, LINE, or DATA connector to at least one of the card edge connector. A center layer includes a grounding plane that is adapted to reduce cross-talk between tracings on a top layer and tracings on a bottom layer. The grounding plane is co-planar with tracings on the center layer such that the grounding plane adds additional thickness to the center layer.
    Type: Grant
    Filed: June 29, 2001
    Date of Patent: October 12, 2004
    Assignee: ADC Telecommunications, Inc.
    Inventor: Paul W. Schmokel
  • Patent number: 6801627
    Abstract: The disclosure relates to localization of an acoustic image out of the head in hearing a reproduced sound via headphone, and includes the steps of: with audio signals S1-S11 of left, right channels reproduced by an appropriate audio appliances as input signals, branching the input signals of the left and right channels to at least two systems; to form signals of each systems corresponding to the left, right channels with left, right speaker sounds imagined in an appropriate sound space with respect to the head of a listener wearing a headphone Hp and virtual reflected sound in the virtual sound space SS caused from a sound generated from the left and the right virtual speaker SPL, SPR, creating a virtual speaker sound signal by processing so that the virtual speaker sounds from the left and the right speakers are expressed by direct sound signals, and virtual reflected sound signals by processing so that the virtual reflected sound is expressed by reflected sound signals; mixing the direct sound signal and re
    Type: Grant
    Filed: September 29, 1999
    Date of Patent: October 5, 2004
    Assignees: OpenHeart, Ltd., A Limited Responsibility Company, Research Network
    Inventor: Wataru Kobayashi
  • Patent number: 6798887
    Abstract: A key click masker and method for disguising key clicks protect sensitive information by randomly varying key click echo generated by a computer system. The key click masker and method disguise the actual keystrokes by generating sounds that would confuse a listener trying to determine the actual keystrokes entered by a user while the user is inputting sensitive information on an input device.
    Type: Grant
    Filed: June 25, 1999
    Date of Patent: September 28, 2004
    Assignee: International Business Machines Corporation
    Inventor: Robert Floyd Andre
  • Patent number: 6795551
    Abstract: A circuit for blocking reception of in-band frequency-shift keyed (FSK) signals by the reception transducer of a telephone subscriber terminal without requiring muting of the reception transducer. The incoming telephone reception signal, which contains both voice and frequency-shift keyed (FSK) signal components, is processed, e.g., within a digital signal processor (DSP), such that the FSK signal component is substantially cancelled. The incoming telephone reception signal is processed to extract amplitude, frequency and phase information, as well as to recover the FSK data clock. This FSK signal information is then used to generate a replica FSK signal for summing with the incoming telephone reception signal to cancel the FSK signal component.
    Type: Grant
    Filed: January 13, 2000
    Date of Patent: September 21, 2004
    Assignee: National Semiconductor Corporation
    Inventors: Theo Ary Asmund Tielens, Renardus Henrikus Maria Kohlmann
  • Patent number: 6795559
    Abstract: An impulse noise reducer detects impulse noise in an audio signal by detecting and smoothing the high-frequency amplitude of the audio signal, attenuating the non-smoothed amplitude according to the smoothed amplitude, and comparing the attenuated amplitude with a threshold. Impulse noise is discriminated from high-frequency audio components because the latter tend to occur in longer-lasting bursts and are therefore attenuated more strongly. The impulse noise reducer is simplified because it does not have to perform intermediate-frequency signal processing, and its sensitivity is not affected by adjacent-channel signals because these signals are substantially absent from the audio signal. The impulse noise reducer can be implemented by digital signal processing, and is suitable for use in a medium-wave AM audio broadcast receiver.
    Type: Grant
    Filed: November 28, 2000
    Date of Patent: September 21, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kenichi Taura, Masahiro Tsujishita, Masayuki Tsuji, Masayuki Ishida
  • Patent number: 6788798
    Abstract: The invention relates to an arrangement for improving leak tolerance in an earpiece. The invention can be applied preferably in teleterminals, particularly in mobile stations. One idea of the invention is that an acoustic return path (314, 313, 311, 312, 320) is directed from the back part of the earpiece capsule (301) to a volume (307) between the earpiece (300) and the user's ear. By means of the solution according to the invention an optimum, controlled load is achieved particularly for low frequencies, such that a change in the volume (307) between the earpiece and the ear only has a minor effect on the volume and quality of the sensed sound. By means of the solution a good leak tolerance is achieved, even though the volume to be arranged behind the earpiece capsule is small.
    Type: Grant
    Filed: October 5, 1998
    Date of Patent: September 7, 2004
    Assignee: Nokia Mobile Phones Ltd
    Inventor: Juha Backman
  • Patent number: 6785391
    Abstract: N correlated signals are processed by N pre-filters whose transfer characteristics have different zero points, then the processed signals are input into an N-input M-output linear FIR system, and its transfer characteristics are estimated from its response outputs and the processed signals from the pre-filters.
    Type: Grant
    Filed: May 21, 1999
    Date of Patent: August 31, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Satoru Emura, Masato Miyoshi
  • Patent number: 6782104
    Abstract: Method intended for the picking up of sounds coming from at least one sound source, for the recording of said sounds and their play-back, by means of a sound pick-up assembly, a recording medium and a transmission assembly. the sound pick-up assembly being composed of at least two microphones, the relative position of which is constant, the recording medium being of any known stereophonic type, particularly with at least two tracks, the transmission assembly comprising at least two members such as earphones, loudspeakers or speaker boxes. It is characterised in that sounds are picked up simultaneously by the two microphones, known as “right” (11) and “left” (12) respectively and that these two microphones (11 and 12) are displaced together with respect to said sound source (A), particularly by causing the distance and/or height of each microphone (11-12) to vary differentially with respect to that source (A), i.e.
    Type: Grant
    Filed: December 28, 1999
    Date of Patent: August 24, 2004
    Assignee: ARKAMYS
    Inventor: Georges Claude Vieilledent
  • Patent number: 6782105
    Abstract: A reflection sound generator has a first filter of Finite Impulse Response (FIR) type that is provided with a first set of parameters representing a first distribution pattern of reflection sounds, and a second FIR-type filter provided with a second set of parameters representing a second distribution pattern of additional reflection sounds. The first distribution pattern has a time length sufficient to cover an initial reflection sound and subsequent reverberant reflection sounds which are distributed at intervals along the time. The first filter executes convolution operation of sample data of an input sound by the first set of parameters to generate first data containing a sequence of reflection sounds of the input sound. The second filter executes convolution operation of the first data by the second set of parameters to generate second data containing additional reflection sounds which fill the intervals of the reflection sounds of the input sound.
    Type: Grant
    Filed: November 23, 1999
    Date of Patent: August 24, 2004
    Assignee: Yamaha Corporation
    Inventors: Shinichi Sahara, Yasushi Shimizu
  • Patent number: 6763106
    Abstract: A signal detector for detecting at least a first signal having a first frequency and a first minimum duration is provided. The signal detector includes a matched transform unit and an energy level detection unit. The matched transform unit is adapted to receive at least a first frame of time domain input samples at a sampling frequency and generate at least a first frequency energy value for the first frame based on at least a first subset of the time domain input samples. The first subset of the first frame has a width of less than about one half of the first minimum duration. The energy level threshold unit is adapted to compare the first frequency energy value to a threshold energy value to determine the presence of the first signal. A method for detecting at least a first signal having a first frequency and a first minimum duration is provided. The method includes receiving at least a first frame of time domain input samples at a sampling frequency.
    Type: Grant
    Filed: November 19, 1998
    Date of Patent: July 13, 2004
    Assignee: Legerity Inc.
    Inventors: Jin Li, Yan Zhou, Vijayakumaran Velayudhan Nair
  • Patent number: 6757396
    Abstract: A digital audio dynamic range compressor includes a root mean square estimator receiving first and second audio input samples and generating root mean square values of the samples. A gain calculator receives the root mean square values and computes a gain for each input sample in the linear domain, not in the logarithmic or dB domain. A minimum selector receives the computed gain of each input sample and determines a minimum. An attack and release filter receives the minimum gain value and filters the minimum gain value according to attack and release coefficients and generate a gain output. A multiplier receives the gain output and multiplies the first and second audio input samples with the gain output.
    Type: Grant
    Filed: September 27, 1999
    Date of Patent: June 29, 2004
    Assignee: Texas Instruments Incorporated
    Inventor: Rustin W. Allred
  • Patent number: 6757385
    Abstract: Processing complexity in an acoustic echo canceller can be reduced by partitioning the input near-end and far-end signals into respective pluralities of frequency subband signals. Also, due to the complex conjugate symmetry of conventional Discrete Fourier Transform matrices, not all of the subband signals of each plurality need be subjected to echo cancellation processing. The subband signals that would have otherwise been produced by echo cancellation processing are instead provided by producing complex conjugates of selected ones of the subband signals that have been subjected to echo cancellation processing.
    Type: Grant
    Filed: May 18, 2000
    Date of Patent: June 29, 2004
    Assignee: Telefonaktiebolaget LM Ericsson (Publ)
    Inventors: Fredrik EhrenstrÄle, Patrik Grundström
  • Patent number: 6754350
    Abstract: A surround reproducing circuit includes a first adder for generating a difference signal of an L signal and an R signal which are inputted, a low-pass filter connected to an output side of the first adder, and second and third adders for mixing an output signal of the low-pass filter as a surround signal with the L signal and the R signal in an opposite phase relationship to each other. Change in a phase is lessened within a frequency band of 20 Hz to 20 KHz and the localization can become definite, and furthermore, a harsh high pass is also lessened. Consequently, it is possible to realize a surround effect having natural spread. Furthermore, the number of capacitors to be required can also be decreased.
    Type: Grant
    Filed: March 22, 2002
    Date of Patent: June 22, 2004
    Assignee: New Japan Radio Co., Ind.
    Inventor: Yositugu Sugimoto
  • Patent number: 6754337
    Abstract: Voice activity is detected by comparing a signal with two thresholds and producing data representing the energy of the signal. The data, in binary form, is compared with thresholds to determine voice activity. In accordance with another aspect of the invention, the thresholds are adjusted based upon statistical information. In accordance with another aspect of the invention, the data can be weighted to provide an indication of the quasi-RMS energy of an input signal. In accordance with another aspect of the invention, voice activity detectors, individually weighted, are provided at each input and each output of a telephone for reliably controlling echo cancelling circuitry within the telephone.
    Type: Grant
    Filed: January 25, 2002
    Date of Patent: June 22, 2004
    Assignee: Acoustic Technologies, Inc.
    Inventors: Steven M. Domer, Kellie Michele Vanda
  • Patent number: 6748077
    Abstract: A replaceable plug which provides voltage surge protector redundancy for use in a maintenance termination unit connecting a telephone company line to a subscriber telephone line. The plug includes connecting terminals for connecting input and output telephone lines to a switch within the plug, and a pair of surge protector circuits. The switch is wired so that it selectively connects one or another of two surge protectors between the input and output lines replacing an actuated protector with a back up protector and restoring telephone service to the subscriber. Associated with this device is a method of determining whether a telephone line fault is due to a protector actuation or in the line proper, and for restoring telephone service without having to send a service person to the location of the maintenance termination box, by providing surge protector redundancy and a switching arrangement whereby a protector is replaced in the line circuit by a switching action.
    Type: Grant
    Filed: March 26, 2002
    Date of Patent: June 8, 2004
    Inventor: Aaron S. Ford