Abstract: A method for compensating for a change in back electric motive force in a transducer in a device, wherein the transducer is driven by an output signal output by an amplifier, and a back volume of the transducer is formed by an enclosure within the device. The method comprises: receiving an input signal; determining, based on a characteristic of the transducer that the transducer has moved from an equilibrium position within the device; and based on the determination, adjusting a gain applied to the input signal by the amplifier to generate the output signal.

Abstract: A method for compensating for a change in back electric motive force in a transducer in a device, wherein the transducer is driven by an output signal output by an amplifier, and a back volume of the transducer is formed by an enclosure within the device. The method comprises: receiving an input signal; determining, based on a characteristic of the transducer that the transducer has moved from an equilibrium position within the device; and based on the determination, adjusting a gain applied to the input signal by the amplifier to generate the output signal.

Abstract: A side tone generator which adjusts gain to compensate for echo effects is described. The side tone generator includes a gain unit which receives a voice signal and applies a gain to the voice signal to produce a side tone, and a summing unit which adds the side tone to a speech decoder signal. The side tone generator also includes a side tone gain adapter to adjust the gain added by the gain unit. The side tone gain adapter computes a default gain which would be applied in the absence of echo and multiplies the default gain by an echo correction factor based on the prevailing level of echo in order to determine the gain to be applied. In another embodiment, an echo canceller employs a filter which receives a filter input based on a speech decoder signal and produces a filter output reflecting an estimate of echo present in the speech decoder signal. The echo canceller also includes an output summing unit which subtracts the filter output from a voice signal to produce an echo canceller output.