Digital circuit transmission device
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorYoshihisa Harada
Life of this patent
Estimating the term…
Abstract
A digital line transmission unit can carry out switching between speech codecs during the same call to achieve balance between making effective use of a line and a high sound quality without bringing about a feeling of discomfort in a user by the switching. It includes in an encoder a first speech codec 7 with a high sound quality and a high bit rate, a second speech codec 8 with a reasonable sound quality but a low bit rate. It carries out switching between these speech codecs in response to the control information an operation monitoring controller 4 obtains by making a decision as to the traffic volume of the bearer line 111. The switching between the speech codecs is made during a speech pause a speech burst detector 31 in a signal detector 3 detects in an input speech signal.
Claims18
A digital line transmission unit for carrying out compression encoding, said digital line transmission unit, comprising:
- an encoder/decoder including
- a first speech encoding unit configured to encode and decode a speech signal,
- a second speech encoding unit configured to encode and decode the speech signal, and
- a non-speech encoding unit configured to encode and decode a non-speech signal;
- a signal discriminator including
- a speech burst detector configured to detect whether an input signal to said encoder/decoder is a speech burst or speech pause, and
- a speech/non-speech signal discriminator for configured to determine whether the input signal is a speech signal or non-speech signal;
- a signal multiplexing/demultiplexing section configured to multiplex outputs of said first encoding unit, said second speech encoding unit, and said non-speech encoding unit;
- an operation monitoring controller configured to output a switch control signal upon determining a change in a state of congestion of a digital line;
- and
- a switching unit configured to switch the input signal between said first, second, and non-speech encoding units,
- upon indication of a change in the state of congestion of the digital line, the switching occurring during a detected speech pause and after terminating encoding of the input signal.
A digital line transmission unit, comprising:
- a plurality of encoders that differ in an encoding scheme or in a bit rate of encoding;
- an interface configured to supply outputs of said encoders to a line;
- a controller configured to output a switch control signal upon determining a change in a state of congestion of the line;
- a speech pause duration measuring section configured to measure a speech pause duration of an input signal to the plurality of encoders;
- and
- a switching unit configured to switch the input signal between said plurality of encoders upon indication of a change in the state of congestion of the line, the switching occurring during a detected speech pause and after terminating encoding of the speech signal when the speech pause duration measured by the speech pause duration measuring section is longer than a preset time period.
Dependencies are inferred from the claim text.