Abstract: An apparatus and method for correctly sensing the state of a 4-pole earmicrophone having two receiver terminals and two common terminals for a microphone and a switch in a mobile terminal. The mobile terminal senses a switch-on of the earmicrophone by mechanical connection between an earmicrophone jack and a jack connector during an earmicrophone connection. The mobile terminal stores information about an earmicrophone state detected by the jack connector. Upon detection of the switch-on of the earmicrophone, the mobile terminal reads the earmicrophone state information from the memory. If the read earmicrophone state indicates earmicrophone disconnection, the mobile terminal mutes transmission and reception, determining that the switch-on is a transient phenomenon.

Abstract: Embodiments include a system and method for adapting a wireless device, such as a Bluetooth-enabled mobile handset or other Bluetooth-enabled device to a car radio and associated speaker system to effect a hands-free car kit or similar system. The adapter module is physically and electrically coupled to the car radio by making electrical contact with a connector on the car radio with a matching connector on one side of the adapter module. The mated connectors provide communications from the adapter module to the car radio. The adapter module includes circuitry for communicating with the Bluetooth-enabled mobile handset and the car radio in order to exchange communications signals between the Bluetooth-enabled mobile handset, and a microphone and the car radio.

Abstract: A wireless local area network and location system for locating objects within a monitored environment are disclosed. A plurality of access point stations receive and transmit communication signals within a wireless local area network. A processor is operatively connected to each of the access point stations and operative for processing communication signals received from the mobile station and, in one embodiment, determining which communication signals are first-to-arrive signals and conducting differentiation of the first-to-arrive signals to locate a mobile station. Delayed versions of at least one interference signal are weighted and the amplitude and phase controlled with weighted functions W1, W2 . . . Wn. The resultant weighted replicas are summed to determine an approximation of disbursed interference for cancelling interference. The location system can include a tag transmitter and spaced monitoring receivers and processor.

Abstract: In one embodiment, a mobile station such as a dual-mode, AMPS and CDMA, handset communicates with an AMPS base station in a wireless communication system. The mobile station includes an acoustic echo canceller, which can detect acoustic echo, for example, feedback from the handset speaker to the handset microphone, during communication between the mobile station and the base station, and cancel or eliminate the acoustic echo. The mobile station also includes a network echo suppressor coupled to the acoustic echo canceller. For example, the network echo suppressor can read a parameter set by the acoustic echo canceller. The network echo suppressor attenuates or mutes a network echo caused by portions of the communication returning to the mobile station from the base station after a network propagation delay. Coupling the network echo suppressor to the acoustic echo canceller ensures proper interaction between the network echo suppressor and acoustic echo canceller.

Abstract: Methods and apparatus for echo and noise cancelation contemplate occasional saturation of an echo and/or noise containing source signal and control adaptation of a cancelation filter to minimize the detrimental effects of such source signal saturation. According to exemplary embodiments, filter coefficients of an adaptive filter are updated only when a prevailing value of the source signal is within a predetermined range of possible source signal values. Consequently, the filter response is not perturbed by source signal saturation, and the adaptive filter continues to provide quality echo suppression even immediately following periods of saturation.

Abstract: The invention relates to a method and a filter for distinguishing signal components from one another, whereof at least one comprises a periodic signal sequence. In the solution samples are taken during several signal sequences (300) and a signal sequence model is formed by arranging the samples taken from several signal sequences (300) together so that the samples represent a single signal sequence (300) model and the signal sequence model is specified by filtering.

Abstract: Programmable echo cancellation filter for echo signal cancellation for a transceiver having a signal input (13) for receiving the transmission signal emitted by the transceiver (1), an input resistor (36) connected to the signal input (13), an operational amplifier (39), whose signal input (38) is connected to the input resistor (36) and whose signal output (41) is connected to an output resistor (43), a first programmable resistor circuit (48), which is provided between the signal output (41) of the operational amplifier (39) and the signal input (38) of the operational amplifier, a second programmable resistor circuit (51), which is provided between the output resistor (43) and a signal output (15) of the echo cancellation filter (14), a third programmable resistor circuit (55) which is provided between the first programmable resistor circuit (48) and the signal output (15) of the echo cancellation filter (14), the programmable resistor circuits (48, 51, 55) each having a plurality of resistors (65) which a

Abstract: Apparatus and method for reducing the sound in surrounding areas when a user is speaking into a communication device such as wireless cell phone. A communication device may be provided with a sound-absorbing body and attachment means may be provided for positioning the body in an operable position adjacent to or in proximity to the receiver or input area of the phone without substantially blocking passage of the speech from the user into the input area. The body may be in the form of a talk screen, which is selectively positionable between an operable position described above, and a non-operable position. Desirably, when in the non-operative position, the apparatus is more compact and does not occupy additional space or as much space as when in the operative position, and is more convenient to transport and store. The illustrated structures show various forms or shapes of screens, some of which are generally flat, while others are arcuate or curved to better provide the desired containment and absorbing.

Abstract: A telephone includes a transmit channel and a receive channel, each including a bank of sub-band filters having a VAD coupled one to each sub-band filter. Each VAD measures the spectral energy in a sub-band, compares the spectral energy to a first threshold, and produces an output signal representative of whether or not the first threshold is exceeded. The voice activity detector also includes a threshold circuit for calculating a dynamically adjustable noise threshold based upon averaged measured spectral energy. A wide band or system VAD monitors echo canceling circuitry to detect voice activity and double talk. A dynamic balance control circuit maintains the transmit and receive channels in a predetermined energy ratio during double talk.

Abstract: Data portion transmission power controlling section 108 increases/decreases the transmission power of the transmitting data to communication terminal apparatus A according to TPC from TPC command decoding section 106. Data portion transmission power controlling section 109 increases/decreases the transmission power of the transmitting data to communication terminal apparatus B according to TPC from TPC command decoding section 107. Midamble portion transmission power value determining section 100 adjusts the transmission power value to the transmission power value which is maximum among transmission power values of transmitting data to communication terminal apparatus A and communication terminal apparatus B, and controls the transmission power of a midamble portion to be transmitted commonly to all communication terminal apparatuses.

Abstract: A communication system (network), such as communication system is a millimeter wave (MMW) communication system, comprise a serial chain of nodes, comprising a middle node (#1) a first adjacent node (#2) on a one side of the middle node and a second adjacent node (#3) on an opposite side of the middle node, each of the middle, first adjacent and second adjacent nodes comprising a transmitter and a receiver, a first antenna at the middle node (#1) for transmitting and receiving over a first link with the second adjacent node (#3), a second antenna at the middle node (#1) for transmitting and receiving over a second link with the first adjacent node (#2) and means for performing interference cancellation in one or both of the transmitter and receiver of the middle node. Various embodiments of multidimensional equalizer are disclosed for performing interference cancellation.

Abstract: A method of noise suppression to suppress noise in a signal containing background noise (314) in a communications path between a cellular communications network and a mobile terminal. The method comprises the steps of: estimating and up-dating a spectrum of the background noise (332, 334); using the background noise spectrum to suppress noise in the signal; generating an indication to indicate the operation of at least one of a discontinuous transmission unit (DTX) and a bad frame handling unit (BFI); and freezing estimating and up-dating of the spectrum of the background noise when the indication is present.

Abstract: An apparatus and method to reduce interference in a communication device particularly effective for second-order interference in direct conversion receiver from a co-located transmitter. This is accomplished by characterizing a transfer function of a transmission path from the transmitter to the receiver and applying this transfer function to the baseband signal from the transmitter to provide an estimation of interference to be expected in the received signal. The estimated interference is subtracted from the receiver baseband signal to reduce interference. Adaptive filtering can also be applied to further minimize interference dynamically.

Abstract: A noise blanker (40, 106) monitors and removes noise from a sampled signal by adaptive filtering (98, 150) the sampled signal to generate trained adaptive filter prediction coefficients. The sampled signal is provided as an output signal when the noise blanker is in a training mode. A noise monitor (34, 154) detects whether noise contained within the sampled signal exceeds a predetermined threshold and provides a control signal in response to the detecting. The noise blanker is placed in a prediction mode for a predetermined amount of time in response to asserting the control signal. A prediction output signal is generated using a plurality of prediction coefficients as an all-pole filter. The prediction output signal has minimal noise content.

Abstract: In a CDMA receiver which receives, as a reception signal (33), a signal given by subjecting a data signal comprising predetermined pattern data (PS) to spread modulation by the use of a spread code, a correlation value calculating unit (701-703) produces correlation value data obtained by multiplying the reception signal by the spread code and the predetermined pattern data. A signal-to-interference ratio calculating portion (74) calculates a signal-to-interference ratio of the reception signal. A reception timing determining portion (76) determines a reception timing of the predetermined pattern data in response to the correlation value data and the signal-to-interference ratio.

Abstract: A bi-directional hands-free communication device includes a microphone for transmitting a signal along a transmit path and a speaker receiving a signal transmitted along a receive path and outputting a corresponding output signal. An echo canceller, positioned in the transmit path and the receive path, cancels echo signals induced by the microphone from the speaker and outputs a corresponding cancelled signal along the transmit path, and a transparency circuit distributes state-dependent additional loss derived from the noise floor margin to the transmit path and the receive path to reduce residual echo signals output from the echo canceller.

Abstract: A portable telephone comprises a case fitted with an antenna and pierced with communications openings in one face associated with a speech microphone and with an earpiece. The telephone also has a directional anti-noise microphone connected to the earpiece via an active anti-noise circuit and associated with a first opening that is separate from the communications openings of the speech microphone and of the earpiece.

Abstract: An electrical circuit in a communications channel is provided. The electrical circuit includes an active resistive summer. The active resistive summer has a composite signal as an input. The composite signal includes a transmission signal component and a receive signal component. A replica transmission signal is also an input to the active resistive summer. The active resistive summer includes the receive signal component as an output.

Abstract: A full-duplex speakerphone that is coupled to a network such as the public switched telephone network. The full-duplex speakerphone includes a base station, which has a network connection and receives a network signal from the network. The base station also includes a speaker for audibly outputting a signal derived from the network signal into a room in which the speakerphone is located. The base station also includes a wireless receiver for receiving signals transmitted over the air from a wireless remote microphone equipped with a wireless transmitter, the received signals being sent by the base station over the network.

Abstract: Bidirectional differential point to point simultaneous high speed signalling is provided between integrated circuits with highly effective echo canceling. Each integrated circuit comprises a transmitter for transmitting a first signal to another integrated circuit and a receiver for receiving a second signal from the other integrated circuit. The transmitter has an output buffer; a receiver has a receiver buffer and is co-located on the same integrated circuit; and a differential buffer is coupled between the input of the transmitter buffer and the output of the receiver buffer. To increase the quality of receiving the second signal, a third signal adjusted in phase and amplitude is coupled at the output of the receive buffer, so that the echoing of the first signal is canceled. Preferably, the rise time of the third signal is also adjusted.

Abstract: A method and apparatus for reducing echo feedback in a wireless communication system (10) is accomplished when a receiving communication unit (24) senses a feedback signal, or echo, via an ancillary communication path. The receiving communication unit is a targeted recipient of an original audio signal generated by a transmitting communication unit (22), where the original audio signal (42) is conveyed to the receiving communication unit. Upon detecting the feedback signal and determining that it exceeds a feedback threshold, the receiving communication unit attenuates an audible output of the original signal to reduce echo to the transmitting communication unit. In addition, the receiving communication unit, and/or the transmitting communication unit include echo canceller to further minimize the echo within the digital communication system.

Abstract: A method of canceling echoes in a telecommunications system wherein an exchange of information takes place between a local subscriber and a subscriber at the remote end of a transmission link and at least one subscriber is assigned an echo canceller, the parameters of which are set as a function of an echo delay time (i). The signs of the signal x(t) transmitted by a subscriber and the signal y(t) received by the subscriber can be determined at equidistant time intervals (Ti) so that sign sequences arise which are stored and compared with one another, and in the event of a direct correspondence or a correspondence as a result of an inversion of the sign sequences of the received signal y(t) and of the transmitted signal x(t) the received signal y(t) is detected as an echo and the echo delay time (i) is calculated.

Abstract: Speech enhancement is provided in dual microphone noise reduction systems by including spectral subtraction algorithms using linear convolution, causal filtering and/or spectrum dependent exponential averaging of the spectral subtraction gain function. According to exemplary embodiments, when a far-mouth microphone is used in conjunction with a near-mouth microphone, it is possible to handle non-stationary background noise as long as the noise spectrum can continuously be estimated from a single block of input samples. The far-mouth microphone, in addition to picking up the background noise, also picks up the speaker's voice, albeit at a lower level than the near-mouth microphone. To enhance the noise estimate, a spectral subtraction stage is used to suppress the speech in the far-mouth microphone signal. To be able to enhance the noise estimate, a rough speech estimate is formed with another spectral subtraction stage from the near-mouth signal.

Abstract: An audio processing module, in accordance with the invention, includes an input for receiving input signals. A side tone generator is included for receiving the input signals and for generating a side tone to be output. A noise suppressor is coupled to the input for suppressing noise of the input signal prior to a coding process, the noise suppressor providing feedback to the side tone generator to adjust a gain of the input signal to the output. A method for adjusting the gain of the side tone generator is also included.

Abstract: A telephone receiving section having a final stage, an electroacoustic transducer having a first terminal connected to the ground of the circuit, a unit for controlling switching on/off, a source of a reference voltage, a switch that can adopt a first position or a second position in order to connect the second terminal of the transducer selectively, via a capacitor, to a reference-voltage terminal of the reference voltage source or to an output terminal of the final stage, respectively, and control means that respond to signals of the unit for controlling switching on/off in order to activate or to deactivate the final stage and the reference-voltage source and to operate the switch in accordance with a predetermined time program. The receiving section operates with the same immunity to disturbances as a fully balanced structure, even though the transducer is not connected between two balanced outputs.

Abstract: A speakerphone arbitration method is used to eliminate the effects of echo in imperfect telephone circuits. The method assumes that speech energy received at the speaker phone is an echo, unless the speech energy has characteristics that indicate it is not echo, such as the duration of the speech energy, and the time at which the speech energy is received relative to the time when the user of the speakerphone finishes speaking, or pauses while speaking. The method also may allow arbitration if the speech energy is more energetic than a typical echo, regardless of the duration or time when it is received.

Abstract: To address the need for an interference-efficient method and apparatus to provide CDMA services, embodiments of the present invention adjust the outer loop frame error rate (FER) target on the forward and reverse links (110-113) while providing communication services to remote units (101-102). At times during a service when a link is conveying primarily “empty” eighth rate frames, the FER target for that link is increased. This improves system capacity by effectively reducing the power needed to transmit such frames and thereby reducing the resultant interference.

Abstract: A communication device (10,110) includes an earpiece (14), a sensor (20), and an active equalization circuit (22). The earpiece (14) transmits an acoustic output signal (59) from the communication device (10,110). The sensor (10) is proximately located with the earpiece (14) and measures an acoustic pressure (61) at the earpiece (14) and generates a response signal (56). The active equalization circuit (22) is coupled to the sensor (20) and equalizes the acoustic output signal (59) using the response signal (56).

Abstract: An echo suppressor for bi-directional communications includes an echo canceler and a residual echo suppressor having variable gain. The gain of the residual echo suppressor is controlled based on a characteristic, such as the estimated energy, of the residual voice echo, or alternatively the entire residual echo, preferably on a per-frame basis. In some embodiments, the residual voice echo energy is compared against the estimated non-echo energy to determine the required amount of gain to apply so as to attenuate the residual voice echo below a psychoacoustic perception level. In some optional embodiments, comfort noise is added to the output signal after the residual echo suppressor in an amount that corresponds to the amount of signal energy loss through the residual echo suppressor. Thus, in some embodiments, desired voice and background noise (including local background noise and comfort noise) are used to mask the presence of residual echo.

Abstract: A method for improving acoustic sidetone suppression in hands-free telephones, in particular for use in motor vehicles, is described. The telephone has a level discriminator and a plurality of adaptive echo compensation filters each processing a subband. In at least one subband, a further adaptive filter (a shadow filter) of a lower order is connected in parallel with the adaptive echo compensation filter. Spatial changes are detected with the aid of a combined evaluation of a correlation analysis and a residual error comparison of the two competing, adaptive filters.

Abstract: A method cancels interference in a radio signal received in a receiver of a wireless communications network, such as a cellular telephone network. The interfering signals are serially detected, demodulated and decoded. Each of the decoded signals is then regenerated into its analog form and subtracted from the radio signal until a desired signal is recovered.

Abstract: Switching a mobile telephone for selectively receiving or transmitting a voice signal in a speakerphone mode by counting the number of the full-rate voice data received from the sender, and blocking the transmission path from the receiver to prevent the received voice data from being retransmitted through the receiver's microphone to the sender if the number of the full-rate voice data exceeds a predetermined value.

Abstract: According to the invention, at least one acoustic output is connected to at least one acoustic input of a computer appliance having a multiway acoustic output and input system. The acoustic signal that is guided via said connection is supplied to an acoustic echo canceller (F) as a reference signal for levelling with an acoustic signal which is supplied to the acoustic echo canceller (F) by means of at least one other multiway acoustic input which is connected to a microphone (M). Echo filtering is thus made possible in a personal computer because the supplied signals are always timely correlated with one another regardless of the delays in signal processing, whereby said delays are caused by the operating system. Echo filtering allows for handsfree talking when entering voice data.

Abstract: A method of converging a step size control for an adaptive filter of a communication channel is disclosed. This method has the steps of: (1) initializing a nominal step size value and a penalty point value; (2) combining the nominal step size value and the penalty point value to generate a step size value; and (3) dynamically changing the step size value in response to a characteristic measure of a quality of the communication channel. With this method, the step size value is changed by adjusting the nominal step size value, the penalty point value, or both the nominal step size value and the penalty point value.

Abstract: Echo is canceled in a communication device including at least one microphone and a loudspeaker. Signals directed to the loudspeaker are filtered through at least one first filter. The filtered signals are subtracted from signals received by the microphone. At least one second filter filters the subtracted results to produce a signal corresponding to speech signals received by the microphone. At least one third filter filters the subtracted results to produce a signal corresponding to echo from the loudspeaker. The output from the third filter is subtracted from the output from the second filter to produce an echo-canceled signal. The device may include a number of microphones, and the first, second, and third filters may each include a number of filters equal to the number of microphones. The outputs from the second filter may be added, the outputs from the third filter may be added, and the sum of the outputs from the third filter may be subtracted from the sum of the outputs of the second filter.

Abstract: An echo cancellation system measures an average delivery rate of a reference data signal and an average capture rate of an input data signal. From the measured data rates, the system converts the reference data signal to a domain of the input data signal. An echo canceler cancels an echo that may be present in the input data signal based upon the converted reference data signal.

Abstract: An apparatus and method for echo cancellation is presented. The echo canceller comprises an adaptive filter that tracks the impulse response of the echo path and produces an estimate of the echo. Filter adaptation is controlled by a controller based on the rate of the far-end speech signal, the rate of the near-end signal, an acoustic loss measure, and a double talk hangover indicator. The controller may also comprise a step size adaptation unit for determining the adaptation step size of the adaptive filter. In addition, the controller may comprise a noise replacement unit, which controls replacement of the echo residual signal with comfort noise to ensure echo is completely rejected when only the far-end speaker is talking.

Abstract: Speech enhancement is provided in dual microphone noise reduction systems by including spectral subtraction algorithms using linear convolution, causal filtering and/or spectrum dependent exponential averaging of the spectral subtraction gain function. According to exemplary embodiments, when a far-mouth microphone is used in conjunction with a near-mouth microphone, it is possible to handle non-stationary background noise as long as the noise spectrum can continuously be estimated from a single block of input samples. The far-mouth microphone, in addition to picking up the background noise, also picks up the speaker's voice, albeit at a lower level than the near-mouth microphone. To enhance the noise estimate, a spectral subtraction stage is used to suppress the speech in the far-mouth microphone signal. To be able to enhance the noise estimate, a rough speech estimate is formed with another spectral subtraction stage from the near-mouth signal.

Abstract: An arrangement for cancelling an echo returning to a first mobile station (MS1) from a second mobile station (MS2). The arrangement comprises tandem free operation (TFO) and an acoustic echo canceller (AEC) to which criteria have been defined, upon fulfillment of which the echo canceller replaces an uplink speech signal of the second mobile station (MS2) by comfort noise (CN) in a second coding format. In accordance with the invention, the echo canceller (AEC) generates additional information (AI) if the tandem free operation (TFO) is active and if criteria for replacing the speech signal with the comfort noise are fulfilled at the same time. In response to said additional information (AI), a first transcoder (TRAU1) encodes the speech signal to be transmitted to the first mobile station (MS1) by using the comfort noise (CN) that is generated by the echo canceller (AEC) and that is in the second coding format.

Abstract: A mobile phone or other personal communication device includes resources applying measures of an individual's hearing profile, personal choice profile, and induced hearing loss profile, separately or in combination, to build the basis of sound enhancement. A personal communication device thus comprises a transmitter/receiver coupled to a communication medium for transmitted receiving audio signals, control circuitry that controls transmission, reception and processing of call and audio signals, a speaker, and a microphone. The control circuitry includes logic applying one or more of a hearing profile of the user, a user preference related hearing, and environmental noise factors in processing the audio signals. The control circuitry may includes instruction memory and an instruction execution processor such as a digital signal processor.

Abstract: The present invention relates to an audio-visual communication device (SB) and an associated method. Said audio-visual communication device has two reception paths, one video (VRP_B) and one audio (ARP_B), said paths being suitable for receiving a video signal (VS) and an audio signal (AS), respectively, originating from a second audio-visual communication device (SA). Said device is characterized in that it comprises means of return control (CNTRL) suitable for adapting an image frequency (FR) of said video signal (VS) as a function of a noise signal.

Abstract: When a microcomputer of an electronic control unit determines that an ACC switch undergoes OFF-ON shift, the mobile telephone is controlled to shift the power supply state from the power supply OFF to the power supply ON. If the time passing after the ACC switch undergoes the OFF-ON shift is within a certain period of time, the mobile telephone is controlled to maintain the power supply OFF state. Therefore, even when the ACC switch is turned on and off repeatedly, it is prevented that the power supply of the mobile telephone is turned on and off repeatedly in connection with the repetition of the ON/OFF of the ACC switch.

Abstract: A cellular phone cradle device for receiving a cellular phone which is detachably connected to a plug-in receptacle on the dashboard or console of a vehicle. The cellular phone cradle device includes a base cradle member having a receiving compartment for receiving a cellular phone. The base cradle member also includes interfacing electrical ports for connecting to the electrical ports of the cellular phone. A plug-in adapter is included which is detachably connected to a plug-in receptacle of a vehicle for providing power to the base cradle member and the plug-in adapter has an interior electrical connector port. A flexible extension coupling is included which is hollow and has an internal channel for receiving at least one electrical connector wire extending therethrough for electrical connection to the interior electrical connector port of the plug-in adapter, and for electrical connection to the base cradle member.

Abstract: A way of reducing undesirable audio signals is provided. A portable device is provided that comprises a sensor to sense an audio signal and a control unit that is communicatively coupled to the sensor. The control unit is provided to receive a first audio signal from a storage unit and to generate a second audio signal based on at least a portion of the sensed audio signal to reduce an undesirable audio signal. The control unit is further provided to combine the first audio signal and the second audio signal and to provide the combined signal through a speaker.

Abstract: The present invention provides a portable, pocket sized speakerphone device adaptable for use with a cellular telephone, and a method for making such a device. The device reduces howling, including echoing and feedback, sufficiently to enable use of the device as a telephone speakerphone. To reduce howling, one or more of the following may be utilized: attenuation circuitry; sound insulation means; positioning the loudspeaker and the microphone of the device such that the outlet of the loudspeaker for emitting sound from the loudspeaker faces in the same direction as the outlet of the microphone for receiving sound into the microphone, and such that a line extending between the outlet of the loudspeaker and the outlet of the microphone would form a right angle with a line extending in the direction of the outlet of the loudspeaker and the outlet of the microphone face.

Abstract: In one embodiment, a mobile station such as a dual-mode, AMPS and CDMA, handset communicates with an AMPS base station in a wireless communication system. The mobile station includes an acoustic echo canceller, which can detect acoustic echo, for example, feedback from the handset speaker to the handset microphone, during communication between the mobile station and the base station, and cancel or eliminate the acoustic echo. The mobile station also includes a network echo suppressor coupled to the acoustic echo canceller. For example, the network echo suppressor can read a parameter set by the acoustic echo canceller. The network echo suppressor attenuates or mutes a network echo caused by portions of the communication returning to the mobile station from the base station after a network propagation delay. Coupling the network echo suppressor to the acoustic echo canceller ensures proper interaction between the network echo suppressor and acoustic echo canceller.

Abstract: Methods and apparatus for providing speech enhancement in noise reduction systems include spectral subtraction algorithms using linear convolution, causal filtering and/or spectrum dependent exponential averaging of the spectral subtraction gain function. According to exemplary embodiments, successive blocks of a spectral subtraction gain function are averaged based on a discrepancy between an estimate of a spectral density of a noisy speech signal and an averaged estimate of a spectral density of a noise component of the noisy speech signal. The successive gain function blocks are averaged, for example, using controlled exponential averaging. Control is provided, for example, by making a memory of the exponential averaging inversely proportional to the discrepancy. Alternatively, the averaging memory can be made to increase in direct proportion with decreases in the discrepancy, while exponentially decaying with increases in the discrepancy to prevent audible voice shadows.

Abstract: A speakerphone arbitration method is used to eliminate the effects of echo in imperfect telephone circuits. The method assumes that speech energy received at the speaker phone is an echo, unless the speech energy has characteristics that indicate it is not echo, such as the duration of the speech energy, and the time at which the speech energy is received relative to the time when the user of the speakerphone finishes speaking, or pauses while speaking. The method also may allow arbitration if the speech energy is more energetic than a typical echo, regardless of the duration or time when it is received.

Abstract: Radio-frequency (RF) apparatus includes receiver analog circuitry that receives an RF signal and provides at least one digital signal to receiver digital circuitry that functions in cooperation with the receiver analog circuitry. The receiver analog circuitry and the receiver digital circuitry are partitioned so that interference effects between the receiver analog circuitry and the receiver digital circuitry tend to be reduced.

Abstract: A digital cellular telephone circuit contains a GPS (Global Positioning System) location circuit, which generates a location code indication signal transmitted to a cellular signal processing station communication server at a local cell base station, when a transmission (telephone call) is placed or received by a cellular user. A program on the server interrogates appropriate ones of various stored databases which contain location information for cell transmission inhibit. Monitoring and control software in the communications server compares the cellular telephone's GPS location against the stored databases of transmission inhibit locations. Such inhibit locations may include GPS highways locations, restricted commerce GPS locations, restricted activity selection, and others. If location or activity transmission inhibit data is found, the control software looks for the presence of an override signal bit. A rejection tone or message may be sent when calls are rejected.