| Patent application number | Description | Published |
|---|
| 20090136020 | METHOD AND APPARATUS FOR ECHO CANCELLATION - A method and apparatus for echo cancellation is disclosed. The apparatus includes an echo compensator and a double talk detector. The echo compensator compensates for associated feedback echo by filtering an echo component from a receiver input signal. The double talk detector provides a control signal based on comparisons of a receiver output signal to a threshold signal and to a transmit signal. The echo compensator also selectively updates filter parameters based on the control signal. | 05-28-2009 |
| 20090141869 | APPARATUS AND METHOD FOR COMPARING SIGNAL STRENGTH IN A SPEAKERPHONE SYSTEM - A method and system for comparing signal strength in a speakerphone system is disclosed. The system is configured to operate in a half-duplex mode, where the direction of communication is determined by comparing signals based on the transmit input signal and the receive input signal. The system estimates and compares the transmit data signal strength and the receive data signal strength. The system then controls a transmit switch and a receive switch to selectively enable transmission based on the comparison. The system also reconfigures the estimation components based on the comparison of the estimated signal strengths. In one implementation, the system estimates the signal envelopes for the inputs and the envelopes of the noise components of the inputs. The system uses the estimates to calculate the data component of the input signals by subtracting the noise envelope from the total signal. A controller compares the strength signals to determine the current state of the system. If one signal is stronger than the other, the controller switches to that state and blocks the weaker signal. The system uses the states to configure the system components. | 06-04-2009 |
| 20090303980 | APPARATUS AND METHOD FOR ERROR CONCEALMENT FOR A DIGITAL WIRELESS PHONE - A method and system to conceal transmission errors in a digital wireless system is disclosed. The system is used in the uplink or the downlink of a cordless or wireless TDMA system. When there are unused data slots available, the system allocates redundant slots in a data frame to a single mobile unit. The receiving device calculates a quality of slot (QoS) score for each slot that it receives data for. After the QoS score is calculated, the system calculates a Quality of Audio Segment (QoAS) score for each individual segment. It does so by comparing the individual audio segments that were received. Segments that are identical are assigned a positive score, while segments that differ get no score. The QoAS for each segment is added to the QoS for the slot the segment was transmitted in to generate the total score. The system then chooses the segment with the highest total score. If the total score is above a specified threshold, the system outputs the segment to the next component. Otherwise, it outputs a mute segment. | 12-10-2009 |
| 20090304131 | LOW COST NOISE FLOOR REDUCTION - A method and system to reduce the noise floor of a communications system is disclosed. The system may be incorporated into any device that provides binary samples from a datastream, such as a cordless telephone system. The system is configured to determine a number of bits of the binary samples that are affected by noise. The system is then able to remove the noise by setting those bits to a fixed value. The fixed value may depend on whether the sample is positive or negative. The value to set may be chosen so that the least significant bits of each sample come as close as possible to 0 for that particular numerical representation system. The system can be integrated with other known signal processing methods. | 12-10-2009 |
| 20100041357 | METHOD AND APPARATUS FOR AUTOMATIC FREQUENCY CORRECTION - A method and apparatus for automatic frequency correction in a demodulation circuit. The apparatus includes a demodulator, a frequency offset estimator, a frequency controller, and an oscillator. The oscillator provides a receiver clock signal which the demodulator employs to demodulate a modulated signal. The frequency offset estimator estimates an offset between a carrier wave frequency of the modulated signal and a frequency of the receiver clock signal. The frequency controller provides a frequency control signal to the oscillator for adjusting the frequency of the receiver clock. While the estimated offset is outside of an adjustment range, the frequency controller maintains the frequency control signal at its previous value. The frequency controller also adjusts the adjustment range based on past error signal values. | 02-18-2010 |
| 20100119055 | SYSTEMS AND METHODS FOR HALF-DUPLEX SPEAKERPHONES AND OTHER TWO-WAY COMMUNICATION DEVICES - An apparatus to enable half-duplexing capabilities in a two-way communication device is disclosed. The apparatus estimates the signal power and background noise of a first input signal and a second input signal during approximately the same period. The apparatus further provides at least one control signal based on the result of one or more determinations. These determinations may include whether the estimated signal power of at least one of the first and second input signals exceeds a threshold value; whether the estimated signal power of the first input signal exceeds the sum of a first threshold value and the estimated background noise of the first input signal; and whether the estimated signal power of the second input signal exceeds the sum of a second threshold value and the estimated background noise of the second input signal. Other embodiments for use with two-way communication devices and related methods are also disclosed. | 05-13-2010 |
| 20100130149 | INTEGRATED SQUELCH CIRCUIT WITH PROGRAMMABLE ENGAGEMENT THRESHOLD - A method, system, and apparatus for squelching a signal in telecommunications systems. The apparatus includes a filter, two power detectors, a divider, two comparators, a logic gate, and a gain control block. The apparatus receives an input signal, and the power of the signal is detected. The input signal is also filtered to pass only the noise portion of the signal, and the power of the filtered signal is detected. A ratio between the filtered signal power and the input signal power is determined. A first comparator receives the filtered signal power and a second comparator receives the ratio of the filtered signal power and the input signal power. The logic gate receives the outputs from the first and second comparators. The gain control block receives as inputs the logic gate's output and the input signal to the apparatus. The gain control block may attenuate the input signal based on the logic gate's output. The gain control block generates the output signal of the apparatus. | 05-27-2010 |
| 20110261975 | LOW COST NOISE FLOOR REDUCTION - A method and system to reduce the noise floor of a communications system is disclosed. The system may be incorporated into any device that provides binary samples from a datastream, such as a cordless telephone system. The system is configured to determine a number of bits of the binary samples that are affected by noise. The system is then able to remove the noise by setting those bits to a fixed value. The fixed value may depend on whether the sample is positive or negative. The value to set may be chosen so that the least significant bits of each sample come as close as possible to 0 for that particular numerical representation system. The system can be integrated with other known signal processing methods. | 10-27-2011 |
