Abstract: A cyclic capillary electrophoresis device includes a capillary channel that forms a closed loop. The capillary channel comprises an inner half facing toward a space enclosed by the loop, where the inner half having an inner wall of first charge density, and an outer half facing away from the space enclosed by the loop, where the outer half having an inner wall surface of second charge density. A difference between the first and the second charge densities exists or can be turned on. The difference is configured to create a smaller average electroosmotic flow velocity in the inner half than in the outer half.

Abstract: A terminal for transmitting a voice signal, comprising: a transmitter having a first transmission module arranged to transmit signals over a packet-switched data network and a second transmission module arranged to transmit signals over a circuit-switched telephony network; a microphone for generating a voice signal; and signal processing apparatus configured to generate a first signal and a second signal from the voice signal, each representing information from the voice signal over a same portion of time. The signal processing apparatus is further configured to supply the first signal to the first transmission module for transmission to a receiver via the packet-switched data network, and to supply the second signal to the second transmission module for transmission to the receiver via the circuit-switched telephony network. There is also provided a terminal for receiving such signals and reconstructing the voice signal, and corresponding methods and program products.

Abstract: A method and system for modifying an audio signal, the method comprising: receiving the audio signal at signal processing means; analysing the received audio signal to identify characteristic signal components in the audio signal; determining that another signal is input to the signal processing means, the input signal resulting from an activity which generates noise in the audio signal; and selectively applying an adjusted gain to the audio signal based on the determination that the input signal is input to the signal processing means, wherein the adjusted gain is generated in dependence upon the signal strength of the identified signal components.

Abstract: An echo component of a first signal received at an audio input device is removed. A second signal is output from an audio output device. The echo component in the first signal is the result of the second signal traversing an echo path. The characteristics of the first and second signals are compared, and if the first signal only comprises the echo, an estimate of the echo path is determined by comparing the first and second signals. The echo path estimate is applied to the first signal to determine an equalized first signal, which is is compared with the second signal to determine an estimate of the echo component. The echo component from the first signal is removed in dependence on the estimate of the echo component.

Abstract: A method of estimating noise in data containing voice information and noise includes receiving the data as a sequence of input values; transforming the data by applying a first non linear mapping to the input values wherein the derivative function of the mapping decreases in magnitude as the input values increase in magnitude smoothing the transformed data; and transforming the smoothed transformed data by applying a second non linear mapping that is opposite to the first non linear mapping, to determine an estimate of the noise in the inputted data.

Abstract: A method and computing system for suppressing noise in an audio signal, comprising: receiving the audio signal at signal processing means; determining that another signal is input to the signal processing means, the input signal resulting from an activity which generates noise in the audio signal; and selectively suppressing noise in the audio signal in dependence on the determination that the input signal is input to the signal processing means to thereby suppress the generated noise in the audio signal.

Abstract: Method, apparatus and computer program product for processing an input stereophonic audio signal to thereby generate a converted stereophonic audio signal representing the input stereophonic audio signal, the input stereophonic audio signal comprising a left input audio signal and a right input audio signal, and the converted stereophonic audio signal comprising a first converted audio signal and a second converted audio signal. The first converted audio signal is generated based on the sum of the left input audio signal and the right input audio signal. The second converted audio signal is generated based on the difference between a first function of the left input audio signal and a second function of the right input audio signal. The first and second functions are adjustable to thereby adjust at least one characteristic of the converted stereophonic audio signal.

Abstract: A method and apparatus for transmitting an audio signal over a communication channel comprising encoding the audio signal with an encoder 204 using a first sampling rate, filtering the audio signal using a first cut off frequency, the first cut off frequency being chosen in dependence upon the first sampling rate, and transmitting the encoded and filtered audio signal over the communication channel. The presence of a condition in which the sampling rate of the encoder 204 is to be switched to a second sampling rate at a switching time is determined and if the condition has been determined to be present, the cut off frequency used in the filtering step is gradually changed from the first cut off frequency to a second cut off frequency, the second cut off frequency being chosen in dependence upon the second sampling rate, such that the audio bandwidth of the transmitted signal changes gradually when the sampling rate is switched to the second sampling rate.

Abstract: A method for reducing ringing in a signal output from a filter comprising inputting a signal into a filter; filtering a first portion of the input signal to generate a filtered portion of the output signal; analyzing the filtered portion of the output signal; detecting if ringing is present in the filtered portion of the output signal based on said analysis; and adjusting the filter characteristics to reduce ringing in a subsequent filtered portion of the output signal if it is determined that ringing is present.

Abstract: A method of processing an audio signal transmitted from a remote transmitter and received at a local receiver of an acoustic system, includes at the receiver receiving with the audio signal an indication of remote transmitter gain, determining an overall system gain of the acoustic system from the remote transmitter gain and a local receiver gain and selectively applying a system gain reduction step to the audio signal if it is determined that the overall system gain exceeds a threshold.

Abstract: Method, apparatus and computer program product for processing an input stereophonic audio signal to thereby generate a converted stereophonic audio signal representing the input stereophonic audio signal, the input stereophonic audio signal comprising a left input audio signal and a right input audio signal, and the converted stereophonic audio signal comprising a first converted audio signal and a second converted audio signal. The first converted audio signal is generated based on the sum of the left input audio signal and the right input audio signal. The second converted audio signal is generated based on the difference between a first function of the left input audio signal and a second function of the right input audio signal. The first and second functions are adjustable to thereby adjust at least one characteristic of the converted stereophonic audio signal.

Abstract: The invention provides a method of controlling transmission of packets from a transmitter to a receiver via a channel, and a corresponding transmitter and receiver. The method comprises: transmitting packets from a queue, each packet having a packet size based on data in the packet; determining a transmission time for each packet, based on a transmission clock; determining a reception time of each packet, based on a reception clock; supplying to an estimation function successive sets of observations including in each set transmission time, reception time and packet size, the estimate function being arranged to provide an estimate of bandwidth for the channel using the relationship between the bandwidth, the amount of data in the queue, packet size and the delay between transmitting successive packets from the queue; and using the estimated bandwidth to control transmission of packets.

Abstract: Method, user terminal, communication system and computer program product for processing audio data for transmission over a network in a communication session between the user terminal and a further user terminal. Samples of audio data which have a sampling frequency and which provide a digital representation of an analog audio signal are transmitted to the further user terminal in the communication session. During the communication session, an estimate of processing resources available for processing audio data in the communication session is repeatedly determined, and the sampling frequency is dynamically adjusted during the communication session based on the determined estimate of available processing resources.

Abstract: An echo component of a first signal received at an audio input device is removed. A second signal is output from an audio output device. The echo component in the first signal is the result of the second signal traversing an echo path. The characteristics of the first and second signals are compared, and if the first signal only comprises the echo, an estimate of the echo path is determined by comparing the first and second signals. The echo path estimate is applied to the first signal to determine an equalised first signal, which is is compared with the second signal to determine an estimate of the echo component. The echo component from the first signal is removed in dependence on the estimate of the echo component.

Abstract: A method for reducing ringing in a signal output from a filter comprising inputting a signal into a filter; filtering a first portion of the input signal to generate a filtered portion of the output signal; analyzing the filtered portion of the output signal; detecting if ringing is present in the filtered portion of the output signal based on said analysis; and adjusting the filter characteristics to reduce ringing in a subsequent filtered portion of the output signal if it is determined that ringing is present.

Abstract: A method for reducing ringing in a signal output from a filter comprising inputting a signal into a filter; filtering a first portion of the input signal to generate a filtered portion of the output signal; analyzing the filtered portion of the output signal; detecting if ringing is present in the filtered portion of the output signal based on said analysis; and adjusting the filter characteristics to reduce ringing in a subsequent filtered portion of the output signal if it is determined that ringing is present.

Abstract: In an embodiment, a method for removing an echo component is a first signal received at an audio input device includes outputting a second signal from an audio output device, receiving at the audio input device the first signal wherein the echo component in the first signal is the result of the second signal traversing an echo path; detecting if the first signal only comprises the echo component; determining an estimate indicative of the echo path by comparing the first signal and the second signal when it is detected that the first signal only comprises echo; applying the estimate indicative of the echo path to the first signal to determine an equalised first signal; comparing the equalised first signal with the second signal to determine an estimate indicative of the echo component; and removing the echo component from the first signal in dependence on the estimate indicative of the echo component; wherein the step of detecting if the first signal only comprises the echo component comprises comparing a char

Abstract: A method for removing an echo component in a first signal received at an audio input device, said method comprising the steps of outputting a second signal from an audio output device, receiving at the audio input device the first signal wherein the echo component in the first signal is the result of the second signal traversing an echo path having a frequency response which defines the relationship between the echo component and the second signal; determining an echo path model indicating an estimate of the frequency response of the echo path; removing an estimate of the echo component from the first signal using the echo path model; detecting if the first signal is overloaded; and wherein if it is detected that the first signal is overloaded the step of determining an echo path model comprises determining an overload echo path model such that the estimate of the frequency response indicated by the overload echo path model is only allowed to increase over time regardless of whether the frequency response of

Abstract: A terminal for transmitting a voice signal, comprising: a transmitter having a first transmission module arranged to transmit signals over a packet-switched data network and a second transmission module arranged to transmit signals over a circuit-switched telephony network; a microphone for generating a voice signal; and signal processing apparatus configured to generate a first signal and a second signal from the voice signal, each representing information from the voice signal over a same portion of time. The signal processing apparatus is further configured to supply the first signal to the first transmission module for transmission to a receiver via the packet-switched data network, and to supply the second signal to the second transmission module for transmission to the receiver via the circuit-switched telephony network. There is also provided a terminal for receiving such signals and reconstructing the voice signal, and corresponding methods and program products.

Abstract: A method and apparatus for transmitting an audio signal over a communication channel comprising encoding the audio signal with an encoder 204 using a first sampling rate, filtering the audio signal using a first cut off frequency, the first cut off frequency being chosen in dependence upon the first sampling rate, and transmitting the encoded and filtered audio signal over the communication channel. The presence of a condition in which the sampling rate of the encoder 204 is to be switched to a second sampling rate at a switching time is determined and if the condition has been determined to be present, the cut off frequency used in the filtering step is gradually changed from the first cut off frequency to a second cut off frequency, the second cut off frequency being chosen in dependence upon the second sampling rate, such that the audio bandwidth of the transmitted signal changes gradually when the sampling rate is switched to the second sampling rate.