Abstract: Techniques for mute pattern injection for a pulse-density modulation microphone are described. In one or more implementations, a pulse-density modulation (PDM) microphone includes a transducer that receives a pressure wave and produces an analog signal that represents the pressure wave, an analog-to-digital converter (ADC) that receives the analog signal from the transducer and converts the analog signal into a digital PDM signal. The PDM microphone also includes a pattern generator that generates a digital mute signal, a controller that outputs control signals, and a multiplexer that receives the control signals, the digital mute signal, and the digital PDM signal. The multiplexer transmits the digital mute signal or the digital PDM signal, responsive to the control signals.

Abstract: Ingress noise from subscriber equipment is mitigated or prevented from reaching a cable television (CATV) network. All upstream signals including ingress noise are initially transmitted to the CATV network whenever their instantaneous power exceeds a threshold which typically distinguishes ingress noise from a valid upstream signal. Whenever the instantaneous power is below the threshold, ingress noise is blocked from reaching the CATV network. A gas tube surge protection device is included to resist component destruction and malfunction arising from lightning strikes and other high voltage, high current surges.

Abstract: A dual-mode encoder. The encoder includes a logic device. The logic device includes a first input terminal for receiving a signal associated with an audio source, a second input terminal for receiving a mode instruction signal, and an output terminal for outputting an encoded signal. The logic device is configured to operate in a first mode by encoding the received associated signal according to a first protocol, and to operate in a second mode by encoding the received associated signal according to a second protocol.

Abstract: An IR receiver having a decision logic circuit for activating or deactivating a squelch. Activation or deactivation of the squelch is effected in dependence on a mean value of the frequency, a variance of the receiver intermediate frequency, a mean value of the audio amplitude, a variance of the audio amplitude and/or a signal strength of the receiver intermediate circuit frequency.

Abstract: In transmitting stream data to a recording unit through a network, there is a method to detect that a synchronous recording has been designated from an input unit to transmit mute data to a recording unit through the network for a first predetermined time period during which the streaming data is held in a data holding unit for the first predetermined time value. In the case where it is determined that the data that the data holding unit holds is held for a second predetermined time value, the inputted stream data is transmitted to the recording unit through the network. The recording unit is permitted to record, in the state where sound is not interrupted, and it is permitted to execute data recording, in which operating time of mechanical parts is required so that the operating state of the recording unit shifts to the recording state, and/or responses relating to the control of the recording unit are taken into consideration.

Abstract: A pulse density modulation, PDM, driver, outputs a PDM stream and can be switched to a control token. The switch takes place when the first integral of the PDM stream has a magnitude less than or equal to a first predetermined value and the second integral of the PDM stream has a magnitude less than or equal to a second predetermined value.

Abstract: In one embodiment, a method includes receiving an input signal in transmitter circuitry of a first semiconductor die and processing the input signal, sending the processed input signal to an isolation circuit of the die to generate a voltage isolated signal, and outputting the voltage isolated signal from the isolation circuit to a second semiconductor die coupled to the first semiconductor die via a bonding mechanism. Note that this second semiconductor die may not include isolation circuitry.

Abstract: Disclosed herein are exemplary techniques for power conservation in a wireless network. A wireless device identifies another wireless device suitable to act as a relay node. Uplink information is transmitted to the other wireless device, which is in turn relayed to an access point for transmission to its destination. Downlink information may be transmitted directly from the access point to the wireless device. The use of a relay node may reduce transmit power consumption as the relay node may be closer to, or support a higher transmit rate, than the access point with which the wireless device is associated.

Abstract: A squelch circuit and a communication apparatus used with the same that are able to generate a squelch signal even if a squelch period is short and an operation of a squelch detecting circuit is insufficient, the circuit having: a squelch detecting circuit detecting the existence of a signal on a communication line in response to a transmission signal or a received signal and generating a first squelch signal; and a squelch control circuit generating a squelch mask signal in response to the first squelch signal and a transmission control signal and generating a second squelch signal based on the squelch mask signal and the control signal. The first squelch signal is controlled by the transmission signal to generate the second squelch signal in which the lacked portion of the first squelch signal is temporally restructured.

Abstract: A shift register receives a quantization difference signal separated into a mantissa part and an exponent part and bit-develops the mantissa part. A shift arithmetic operation control circuit bit-shifts the bit-developed mantissa part in accordance with a value of the exponent part. An overflow detection bit is added to the MSB of the shift register and detects the overflow of the bit-shifted mantissa part. When the overflow of the mantissa part is detected, a selector replaces the bit-developed mantissa part with a predetermined upper limit value and outputs it as a prediction signal. When the overflow is not detected, the selector outputs the bit-developed mantissa part as a prediction signal. An ADPCM decoder having high audio quality is provided by simple processes and construction.

Abstract: A squelch circuit for operating at high speed and at high frequencies includes a squelch input unit, a low swing pre-amplifier and a sampling and decision circuit. The squelch input unit pre-processes the positive and negative signals of an input signal to generate four pre-processed signals that are paired and sent to the low swing pre-amplifier. The outputs of the low-swing pre-amplifier are then over-sampled by the sampling and decision circuit. Multi-phase clocks are used to control the over-sampling in the sampling and decision circuit. A logic circuit then determines if the state of the input signal based on multiple samples.

Abstract: A circuit is connected between a module and a pair of wires. The circuit includes a first connection line, a second connection line, radio frequency termination circuitry, a first transformer, a second transformer, a tapped inductance and a feedback cancellation filter. The first connection line is for connection to a first wire in the pair of wires. The second connection line is for connection to a second wire in the pair of wires. The radio frequency termination circuitry is connected between the first connection line and the second connection line. The first transformer has a first inductance and a second inductance. A first end of the first inductance is coupled to the first connection line. A first end of the second inductance is coupled to the second connection line. The second transformer includes a first inductance and a second inductance.

Abstract: The invention provides a digital broadcast receiver which comprises a tuner 1 for selecting the desired broadcasting station from among a plurality of broadcasting stations, a demodulator circuit 3 for decoding a plurality of bit frames constituting the digital broadcast of the selected station, and a control circuit 4 for controlling the operation of the tuner and the demodulator circuit. With one broadcasting station selected, the control circuit 4 stops decoding at least one of the bit frames, and searches for other broadcasting station or stations of satisfactory reception condition utilizing free time resulting from stopping decoding. Upon the reception condition becoming impaired, the station being received is changed over to the station of satisfactory reception condition by the control circuit 4.

Abstract: Provided is a device for improving voice signal in quality by discriminating a radio environment of a signal transmission path and detecting a click noise. The device for improving voice signal in quality calculates an average value for a short interval of a received ADPCM code, identifies from such average value the nature of a radio environment of a signal transmission path, and considers that a click noise is occurred when the average value exceeds a threshold value assigned radio environment. The present invention comprises a click noise detector (22) for outputting a click noise detecting signal, and a click noise suppressing circuit for suppressing the click noise by setting the velocity coefficient of an ADPCM decoder (21) as “0” for a frame in which a frame error detecting signal, which represents the detection of a frame error of the received ADPCM code, and a click noise detecting signal are both detected.

Abstract: A squelch circuit for operating at high speed and at high frequencies includes a squelch input unit, a low swing pre-amplifier and a sampling and decision circuit. The squelch input unit pre-processes the positive and negative signals of an input signal to generate four pre-processed signals that are paired and sent to the low swing pre-amplifier. The outputs of the low-swing pre-amplifier are then over-sampled by the sampling and decision circuit. Multi-phase clocks are used to control the over-sampling in the sampling and decision circuit. A logic circuit then determines if the state of the input signal based on multiple samples.

Abstract: An echo cancellation functionality taps a digital transmit signal from a transmit channel for processing through an adaptive filter of an echo channel to generate an echo cancellation signal. The adaptive filter has a transfer function substantially matching an echo transfer function which defines a relationship between the transmit signal and an unwanted echo component corrupting an analog receive signal. The echo cancellation signal is digital-to-analog converted to an analog signal and then subtracted from the analog receive signal to substantially cancel out the unwanted echo component. The echo cancellation functionality may be configured in a training mode to generate an error signal used to adaptively configure the adaptive filter transfer function to substantially match the echo transfer function. When in training mode, certain components of an adaptation loop which contribute to a feedback loop transfer function are selectively by-passed.

Abstract: The high-frequency component removing circuit is immediately started, and is not stopped unless the measurement value of the received electric intensity has maintained a value equal to or higher than the filter level for 1 sec after the high-frequency component removing circuit is started. Therefore, when the received electric intensity fluctuates around the filter level during a speech communication, the switching operation of repetitively starting and stopping the high-frequency component removing circuit is suppressed. As a result, the number of times of switching operations that repetitively start and stop the high-frequency component removing circuit is reduced, and the signal tone upon switching can be suppressed from mixing into the audio signal as noise in a speech communication. In addition, even when the received electric intensity fluctuates around the filter level, a speech communication environment that does not allow noise to easily mix can be obtained.

Abstract: The invention relates to an apparatus for processing a signal received via an information carrier. The apparatus comprises a receiving unit (2) for receiving a signal from the information carrier, an equalizer (8) for equalizing the signal thus received, and a signal processing device (12). The signal processing device (12) has a first signal path (14) including time delay means (22), a second signal path including differentiation means adapted to effect at least two differentiations with respect to time, a decision circuit (26), and a controllable switching element (38). The decision circuit (26) is adapted to transfer a control signal, the decision circuit being adapted to supply a control signal which depends upon the signals on the outputs (28, 32) of the first signal path (14) and the second signal path (16).

Abstract: Radio receivers for receiving DTV signals, in accordance with the Advanced Television System Committee (ATSC) standard, or analog TV, in accordance with the National Television Systems Committee (NTSC) standard, each use a single first detector for both types of signal. This single is followed with an intermediate-frequency amplifier providing amplification both for digital television signal and for the amplitude-modulated NTSC video carrier of an analog television signal. Preferably, the shared intermediate-frequency amplifier is a high-band intermediate-frequency amplifier having fixed gain and having its bandwidth determined using a surface-acoustic-wave filter with flat-amplitude midband response, steep-slope skirts, and linear phase throughout its passband.

Abstract: Audio communication apparatus which facilitates reduction of data network traffic. The communication apparatus distinguishes between voice activity and silence or background noise. Upon termination of voice activity the apparatus output the contents of it memory thus far for transmission over the data network. When voice activity is resumed after a period of inactivity, the transmission of voice data is resumed and an indication of the elapsed time between the previous voice samples and the current samples is also transmitted to a receiving terminal to allow correct timing of the output of the resumed transmission of the voice samples.

Abstract: A system and method of muting a voice signal in a wireless communication system when an "all zeros" condition of a digitized serial voice input signal is detected. The mute signal which is generated when a zeros condition occurs is provided to a voice processor to initiate a mute algorithm to mute the processing of incoming voice data during the sample time of the zeros condition.

Abstract: A cellular telephone communication protocol enables a communication link primarily for the transmission of voice and data. At predetermined intervals or on-demand data regarding location, an event, or a condition is sent by muting the voice audio and sending a data frame having a pre-determined sequence. Following the transmission of the location, event, or condition data transmission of voice and data is resumed. The communication link uses a half duplex, frequency shift, keying modulation technique.

Abstract: A device and method for controlling HF single side band radio squelch operation in which a serial tone burst indicates the start and end of a transmission and identifies an on-going transmission. Additionally, receivers in a power saving sleep mode can be activated by receipt of a set of serial tone bursts that have been transmitted with sufficient duration for the receiver to be assured the opportunity to detect them. During the subsequent transmission of information, single "keep-alive" serial tone bursts are transmitted at random time intervals. The end of a transmission is signalled by another set of serial tone bursts. The bursts are provided with the transmitted signal on its frequency and preserve signal bandwidth.

Abstract: A method for providing improved carrier based data operated squelch (CDOS) includes routines for recovering the carrier signal and for analyzing the received signal. The received signal is sampled at each transition point of the carrier signal as well as the halfway points between the transition points. In addition, extra samples are taken between these samples. Using the samples, a carrier locked loop routine recovers the carrier signal. A CDOS routine analyzes the extra samples to determine the presence of data. If two successive samples are different, this means that a transition has occurred. The CDOS routine analyzes these transitions to determine whether the input signal is encoded with data. If the CDOS routine determines that the input signal is encoded with data, a CDOS counter is incremented. As the input continues to look like data, the value by which the CDOS counter is incremented is increased. When the CDOS counter reaches a certain threshold, the CDOS mutes the output circuit.

Abstract: A signal quality detector (200) determines the quality of an incoming received data signal within a communication device (100). The audio output of the communication device is muted and unmuted according to the decision of the signal quality detector (200). The signal quality detector (200) allows the threshold length of an invalid bit period (210), along with the number of invalid bit periods detected (220), to be used to vary the decision sensitivity of the detector.

Abstract: An analog/digital receiver comprises a noise detecting circuit for checking whether a noise component, output from an analog signal detecting means, is not less than a specified value, and an RSSI detecting circuit for checking whether received signal strength, output from the receiver, is not less than a specified value. A discriminating circuit is included for making a determination as to whether the received input is an analog modulation signal or a digital modulation signal according to the result of the determination made by the noise detecting circuit as well as by the RSSI detecting circuit. A select switch selects the output from either the digital signal detecting circuit or the analog signal detecting circuit.

Abstract: A receiver 700 having an audio output device 326 is disclosed. The receiver 700 receives a carrier signal modulated with data, voice, or a combination of both. The receiver 700 includes a demodulator 708 for demodulating the received carrier signal. The demodulated audio signal 302 is coupled to a delay circuit 300 where it is delayed and coupled to a detector 318. The detector 318 detects the presence of data or voice in the demodulated audio signal 302 and mutes or unmutes the audio output device 326 respectively. The delay circuit 300 stops any portion of the data signal to reach the audio output device 326.

Abstract: A wireless communications receiver having an adaptive squelch system and operable in multiple states including a receiver (11) that provides a received signal when operating in a clear (unscrambled) state and when operating in a secure (scrambled) state; a squelch function (13) that generates an unsquelch signal when the received signal satisfies a quality level; and a controller (15) that sets the quality level to a predetermined level that corresponds to the receiver operating state.