Abstract: In order to prevent generation of a trapezoidal signal waveform due to limitations on dynamic ranges in an echo canceller and an echo path as voice signal transmission paths, a voice signal processing circuit of the voice signal processing system processes a waveform such that its signal level falls within the narrowest dynamic range without causing an overshoot and waveform crack. Process of a signal waveform is selectively conducted only of a waveform of a voice signal whose signal level is high to be liable to have distortion. As to a voice signal whose signal level is low and originally within a dynamic range, the signal is transmitted without having its waveform processed.

Abstract: A communication system being made up of a two-wire/four-wire hybrid circuit, an echo canceller, and a control device and having functions of forming a plurality of communication paths and changing communication paths is provided which is capable of ensuring high speech quality by suppressing and canceling an echo occurring in telephone speech after establishment of path connection. The communication system also includes a training signal source to feed a training signal to the echo canceller, a switching circuit to do switching of a signal to be fed to the echo canceller between an ordinary signal and the training signal, and a control device to exert control on path connection and path changing and to feed the training signal to the switching circuit to make a training signal be fed from the training signal source to the echo canceller and to have the echo canceller converge its training operation.

Abstract: A communication system being made up of a two-wire/four-wire hybrid circuit, an echo canceller, and a control device and having functions of forming a plurality of communication paths and changing communication paths is provided which is capable of ensuring high speech quality by suppressing and canceling an echo occurring in telephone speech after establishment of path connection. The communication system also includes a training signal source to feed a training signal to the echo canceller, a switching circuit to do switching of a signal to be fed to the echo canceller between an ordinary signal and the training signal, and a control device to exert control on path connection and path changing and to feed the training signal to the switching circuit to make a training signal be fed from the training signal source to the echo canceller and to have the echo canceller converge its training operation.

Abstract: In order to prevent generation of a trapezoidal signal waveform due to limitations on dynamic ranges in an echo canceller and an echo path as voice signal transmission paths, a voice signal processing circuit of the voice signal processing system processes a waveform such that its signal level falls within the narrowest dynamic range without causing an overshoot and waveform crack. Process of a signal waveform is selectively conducted only of a waveform of a voice signal whose signal level is high to be liable to have distortion. As to a voice signal whose signal level is low and originally within a dynamic range, the signal is transmitted without having its waveform processed.

Abstract: In a vane pump, a bottom surface of a suction side low pressure passage is set to be below a bottom surface of a return passage of a flow control valve in a cross portion between the return passage and the low pressure passage.

Abstract: In a vane pump, a bottom surface of a suction side low pressure passage is set to be below a bottom surface of a return passage of a flow control valve in a cross portion between the return passage and the low pressure passage.

Abstract: A carriage guiding post in a transfer lifter, is a four-sided support post of an approximately square shape in cross section the support post having carriage guiding rail recesses provided in three of the four sides thereof, and a counter weight guiding rail track provided on the remaining side of the support post, the carriage guiding rail recesses and the counter weight guiding rail all extend continuously throughout the length of the support post, wherein the counter weight guiding rail track is a rib projecting from a central region of the side of the support post and extends lengthwise thereof, the rib having an approximately isosceles triangle shaped cross section.