Disclosed is an echo canceller (10) including: a false echo calculator (32) that acquires current and previous filter-coefficient groups used by an adaptive filtering unit (20), and that calculates plural false echo signals by performing a filtering operation using each of the current and previous filter-coefficient groups on a sequence of reception signals (x(n)); a voice-transmission signal buffer that outputs a previous voice-transmission signal (y(n1)); an evaluation value calculator (34) that calculates plural evaluated values of an echo cancellation quantity by using the previous voice-transmission signal; a filter selector (36) that selects a new filter-coefficient group on the basis of the plural evaluated values of the echo cancellation quantity; a foreground filter (39) that performs a filtering operation using the new filter-coefficient group on the sequence of reception signals (x(n)) to generate an estimated echo component; and a subtractor (25) that subtracts the estimated echo component from a voice-transmission signal to generate a residual signal (e(n)).

A multiport FDX data transceiver having (i) digital transmit and receive chains shared by the multiple ports thereof and (ii) a multi-stage echo-cancellation circuit capable of canceling the echo of the transmitted signal that is coupled back into the receive chain through the analog front end of the transceiver. In an example embodiment, the echo-cancellation circuit comprises two stages. The first stage operates to remove a dominant echo signal corresponding to the output signal that is being broadcast on the multiple ports of the transceiver. The second stage operates to remove a residual echo signal typically caused by differences in the pertinent characteristics of the circuits associated with the different ports of the transceiver. In some embodiments, the multi-stage echo-cancellation circuit can be used for training a single-stage echo-cancellation circuit that may be unable to sufficiently quickly converge on an optimal set of filter coefficients on its own.

A cloud based echo canceller is set forth for recreating an estimate of a lost packet or data at a server without requiring redundant data over the network or freezing operation of the echo canceller. In an exemplary embodiment, the echo cancelling function is not located in a single device, but is shared between the end-point and a cloud service, where the function of the end-point is to provide a time synchronized copy of the signal from the end-point loudspeaker and the signal received by the end-point microphone. Consequently, the high CPU intensive operations can be offloaded to a server such as a cloud server. In addition, several users can share the echo canceller, thereby reducing the cost of the overall function. According to an additional aspect, a further synchronization block is provided, in the form of a packet estimator, to compensate for packet or data loss in the send direction.

A carrier frequency offset (CFO) estimation device includes an echo cancelling unit, performing echo cancellation on an input signal to generate an echo-cancelled signal; and a CFO estimating unit, performing CFO estimation on the echo-cancelled signal to generate an estimated CFO.

A method, a device, and a non-transitory storage medium are described in which a full duplex system may use information from a user of the device as a basis to configure parameters of a dynamic range controller system. The parameters may include high pass filter values, compression values, and masking values. The full duplex system may use a pre-distortion filter for generating an estimated echo feedback reference signal. For generating the estimated echo feedback reference signal, the pre-distortion filter uses an echo coupled reference signal via microphone path as a reference signal, and an echo feedback reference signal via speaker feedback path as the input. An echo canceller of the full duplex system may use the estimated echo feedback reference signal, which takes echo path distortion into consideration, for cancelling both linear and non-linear echo.

There is provided a transmission device including: a transmission unit that has a function of transmitting a transmission signal with a reduced influence of reflection noise in transmission data after data transition on the basis of the transmission data.

A cloud based echo canceller is set forth for recreating an estimate of a lost packet or data at a server without requiring redundant data over the network or freezing operation of the echo canceller. In an exemplary embodiment, the echo cancelling function is not located in a single device, but is shared between the end-point and a cloud service, where the function of the end-point is to provide a time synchronized copy of the signal from the end-point loudspeaker and the signal received by the end-point microphone. Consequently, the high CPU intensive operations can be offloaded to a server such as a cloud server. In addition, several users can share the echo canceller, thereby reducing the cost of the overall function. According to an additional aspect, a further synchronization block is provided, in the form of a packet estimator, to compensate for packet or data loss in the send direction.

Updating filter coefficients during echo cancellation is disclosed. In some embodiments, a communication device may include a processor configured to operate a background filter configured as an adaptive filter, operate a foreground filter configured as a fixed filter; and update the foreground filter with coefficients from the background filter responsive to monitoring a history of both a near-end signal energy and an estimated far-end signal energy for a pre-determined time window in which conditions of each of the near-end signal energy and the estimated far-end signal energy are satisfied.

An electronic device, an echo signal cancelling method thereof and a non-transitory computer readable recording medium is provided. The electronic device according to an exemplary embodiment includes a speaker configured to output a sound corresponding to a reference signal, a microphone configured to generate a microphone signal by obtaining a received sound, and a filter configured to cancel an echo signal of the reference signal from the microphone signal. In addition, the filter includes a first filter configured to estimate an echo signal of the reference signal and cancel the estimated echo signal from the microphone signal, and a second filter configured to generate an adaptive gain to cancel a residual echo from the microphone signal in which the estimated echo signal is canceled, and generate an output signal by using the generated adaptive gain and the microphone signal in which the estimated echo signal is canceled.

A method, a device, and a non-transitory storage medium are described in which a full duplex system may use information from a user of the device as a basis to configure parameters of a dynamic range controller system. The parameters may include high pass filter values, compression values, and masking values. The full duplex system may use a pre-distortion filter for generating an estimated echo feedback reference signal. For generating the estimated echo feedback reference signal, the pre-distortion filter uses an echo coupled reference signal via microphone path as a reference signal, and an echo feedback reference signal via speaker feedback path as the input. An echo canceller of the full duplex system may use the estimated echo feedback reference signal, which takes echo path distortion into consideration, for cancelling both linear and non-linear echo.