Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Ichiro Kawashima

Kosuke Nishio

Toshikazu Wakabayashi

Harumasa Kajita

Tetsuo Kariya

Satoshi Nakanami

Toyokazu Yanagimichi

Masami Tanaka

Shuji Miyasaka

Yoshiaki Sawada

Shinji Kojima

Seigo Suguta

Hiroyuki Goto

Naoki Shindou

A communication terminal includes a decoder which decodes an input bitstream received from another communication terminal, to generate an output audio signal and outputs the generated output audio signal to a speaker; and an echo canceller which obtains an input audio signal representing sound captured by a microphone placed in a space to which the speaker outputs the sound, and removes, for respective subbands, an echo component included in the obtained input audio signal and corresponding to the output audio signal, to generate an audio signal for transmission. An encoder codes the audio signal for transmission to generate an output bitstream and transmits the generated output bitstream to another communication terminal; and a control unit controls, for the respective subbands, echo cancellation processing according to a reproduction band of at least one of the output audio signal and the audio signal for transmission.

Communication terminal and communication method

An audio mixing/reproducing device includes an audio decoder () configured to decode an encoded audio input signal, an audio mixer () configured to mix an audio signal output from the audio decoder () with a non-encoded external audio input signal, and an audio encoder () configured to encode an audio signal output from the audio mixer () to generate an encoded audio output signal, and in addition, a switch () configured to generate a switch signal for controlling operations of each of the audio decoder () and the audio encoder () in response to a switch activation signal. The audio decoder () and the audio encoder () each support a plurality of encoding schemes, and the switch (), when switching the encoding scheme of the audio decoder () from a first encoding scheme to a second encoding scheme, controls the audio decoder () and the audio encoder () so that the encoding scheme of the audio encoder () is switched from the first encoding scheme to the second encoding scheme as in the audio decoder ().

Audio mixing/reproducing device

A general-purpose processor expands and transmits to a volatile memory compressed program data and compressed parameter data stored in a nonvolatile memory. The DSP processor reads the expanded program data and the expanded parameter data into a program memory and the data memory of the DSP processor, respectively, and then, decodes compressed digital data or encodes expanded digital data.

Encoding/decoding device for compressing or expanding digital data

When underflow of a sub-Q data table occurs, a sub-Q data processing section does not read and output sub-Q data but outputs only audio data. Moreover, to achieve consistency between audio data and the sub-Q data in terms of buffer management, an input processing section includes respective counters for managing respective input data amounts of the audio data and the sub-Q data. Then, the input processing section executes management so that overflow and underflow of the sub-Q data table are suppressed as much as possible and a switch changes an IEC output mode at a time of audio processing and a time of dubbing. Thus, sound deterioration, and error recording in equipment to which the audio player is connected, and the like can be prevented.

Audio player

A key signal conversion device for use in a CATV television system in which more than one different scrambling process is performed, the conversion device receiving one of a scrambled high-frequency signal in a television system and a sound intermediate frequency signal in the television system, extracting a key signal for unscrambling the scrambling in the television system and adding the key signal to a nonscrambled television signal which is to be subsequently scrambled by a process other than a process used to scramble the received signal, the key signal conversion device including: a first detecting circuit, for receiving the one of a scrambled television signal and a sound intermediate frequency signal, and for detecting one of a synchronizing signal of the television signal and a synchronizing signal superimposed on the sound intermediate frequency signal; a gate circuit, for receiving the one of a scrambled television signal and a sound intermediate-frequency signal, and for extracting the key signal therefrom using the synchronizing signal detected by the first detecting circuit; a second detecting circuit, for receiving the nonscrambled television signal, and for detecting a synchronizing signal thereof; and an inserting circuit for superimposing the key signal on the nonscrambled television signal in a predetermined horizontal interval in the vertical blanking interval of the nonscrambled television signal by the gate circuit using the signal detected by the second detecting circuit.

Key signal conversion device for CATV system

A cable television system includes a transmitter and at least one receiver. In the transmitter, sync information is suppressed in amplitude to execute scrambling, and a sync width information signal and key data are superimposed on a television signal during a vertical blanking period. The sync width information signal has a burst form and a predetermined width, and represents whether sync information is present or absent. The key data represents contents of the scrambling. In the receiver, the sync width information signal is recovered, and a sync width information pulse corresponding to the sync width information signal is generated. A reference signal is generated on the basis of an edge of the sync width information pulse. The key data is extracted from the scrambled video information in response to the reference signal. Pseudo sync signals are generated in response to an edge of the sync width information pulse. The sync information of the scrambled video information is increased in amplitude in response to the extracted key data at timings determined by the pseudo sync signals.

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Osaka, Japan

Ichiro Kawashima