Data processing: speech signal processing – linguistics – language – Speech signal processing – For storage or transmission
Reexamination Certificate
1999-10-26
2001-12-04
Dorvil, Richemond (Department: 2641)
Data processing: speech signal processing, linguistics, language
Speech signal processing
For storage or transmission
C704S201000, C704S270000
Reexamination Certificate
active
06327563
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an audio signal coding apparatus, a wireless microphone using the audio signal coding apparatus, an audio signal decoding apparatus, and a wireless microphone system using the audio signal coding apparatus and the audio signal decoding apparatus.
2. Description of the Prior Art
An audio signal coding apparatus for coding an audio signal to output a compressed audio signal, a wireless microphone transmitting a sound signal, and a wireless microphone system including a wireless microphone and a receiver for receiving the transmitted sound signal from the wireless microphone, and an audio signal decoding apparatus for decoding the compressed audio signal are known.
SUMMARY OF THE INVENTION
The aim of the present invention is to provide a superior audio signal coding apparatus, a superior wireless microphone, a superior wireless microphone system, and a superior audio signal decoding apparatus.
According to the present invention, a first audio signal coding apparatus is provided, which includes: a band separating filter for separating a digital audio signal into M bands of audio data; a quantizing circuit for quantizing M bands of the audio data; and a data grouping circuit for grouping M bands of the audio data to output N bands of the audio data. M and N are natural numbers more than one and M>N.
The first audio signal coding apparatus may further include: a magnification determining circuit for detecting maximum levels of M bands of the audio data and determining M bands of magnifications in accordance with M bands of the maximum levels; a normalizing circuit for normalizing M bands of the audio data from the band separating filter in accordance with M bands of the magnifications and supplying normalized M bands of the audio data to the quantizing circuit; a bit assignment determining circuit for determining bit assignment of M bands of the audio data in accordance with M bands of the audio data to generate M bands of bit assignment data supplied to the quantizing circuit, wherein the quantizing circuit quantizes M bands of the audio data in accordance with the bit assignment of M bands of the audio data, the data grouping circuit groups M bands of the audio data, the magnifications, and the bit assignment data into N bands of audio data, magnifications, and bit assignment data. The first audio signal coding apparatus may further include a bit stream forming circuit for generating and outputting a bit stream from N bands of the audio data, the magnifications, and the bit assignment data from the grouping circuit.
According to this invention, there is provided a first audio signal decoding apparatus including: a receiving circuit for receiving a bit stream including audio data which are grouped into N bands from M bands of audio data which is generated from an audio signal, M and N being natural numbers more than one, M>N; a coded data separating circuit for separating N bands of the audio data to M bands of the audio data; a de-quantizing circuit for de-quantizing M bands of the audio data; and a combining circuit for combining M bands of the audio data into an output audio signal.
According to this invention, there is provided a first wireless microphone which includes: a microphone for receiving a sound to generate a sound signal; an a/d converter for a/d-converting the sound signal into audio data; a compressing circuit for compressing the audio data in accordance with frequency resolution of the human being to generate compressed audio data; and a transmitting circuit for transmitting the compressed audio data.
In the first wireless microphone, the compressing circuit may include: a band separating filter for separating audio data into M bands of audio data; a quantizing circuit for quantizing M bands of the audio data; and a data grouping circuit for grouping M bands of the audio data to output N bands of the audio data as the compressed audio data in accordance with frequency resolution of the human being. M and N are natural numbers more than one, M>N.
According to this invention, there is provided a wireless microphone system which includes: a microphone unit including: a microphone for receiving a sound to generate a sound signal; an a/d converter for a/d-converting the sound signal into audio data; a compressing circuit for compressing the audio data in accordance with frequency resolution of the human being to generate compressed audio data; and a transmitting circuit for transmitting the compressed audio data; and a receiving unit including: a receiving circuit for receiving the compressed audio data transmitted by the transmitting circuit; and an expanding circuit for expanding the compressed audio data from the receiving circuit in accordance with the frequency resolution to output expanded audio data.
According to this invention, there is provided a second audio signal coding apparatus which includes: a band separating filter for separating a digital audio signal into M bands of audio data; a bit assignment determining circuit for determining bit assignment and generating M bands of bit assignment data in accordance with M bands of the audio data; a magnification determining circuit for detecting M bands of maximum levels of M bands of the audio data and determining M bands of magnification data in accordance with M bands of the maximum levels; a data grouping circuit for grouping M bands of the magnification data into N bands of magnification data and grouping M bands of the bit assignment data into N bands of assignment data to output N bands of magnification data and N bands of assignment data; a combining circuit for combining M bands of the audio data into N bands of audio data; a normalizing circuit for normalizing N bands of the audio data from the band separating circuit in accordance with N bands of magnification data; and a quantizing circuit for quantizing N bands of the audio data in accordance with N bands of the bit assignment data to output the quantized N bands of the audio data. M and N are natural numbers more than one, M>N.
According to this invention, there is provided a second wireless microphone which includes: a microphone for receiving a sound to generate a sound signal; an a/d converter for a/d-converting the sound signal into audio data; a band separating circuit for separating the audio data into M bands of audio data; a bit assignment determining circuit for determining bit assignment and generating M bands of bit assignment data in accordance with M bands of the audio data; a magnification determining circuit for detecting M bands of maximum levels of M bands of the audio data and determining M bands of magnification data in accordance with M bands of the maximum levels, respectively; a data grouping circuit for grouping M bands of the magnification data into N bands of magnification data and grouping M bands of the bit assignment data into N bands of assignment data to output N bands of magnification data and N bands of assignment data; a combining circuit for combining M bands of the audio data into N bands of audio data; a normalizing circuit for normalizing N bands of the audio data from the band separating circuit in accordance with N bands of magnification data; and a quantizing circuit for quantizing N bands of the audio data in accordance with N bands of the bit assignment data to output the quantized N bands of the audio data. M and N are natural numbers more than one, M>N.
According to this invention, there is provided a third audio signal coding apparatus which includes: a band separating filter for separating a digital audio signal into M bands of audio data; a magnification determining circuit for detecting maximum levels of M bands of the audio data and determining M bands of magnification data in accordance with M bands of the maximum levels; a normalizing circuit for normalizing M bands of the audio data from the band separating filter in accordance with M bands of magnification data; a bit assignment determining circuit for
Dorvil Richemond
Matsushita Electric - Industrial Co., Ltd.
Nolan Daniel A.
Woo Louis
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