Wireless microphone system

• US 6,327,563 B1
• Filed: 10/26/1999
• Issued: 12/04/2001
• Est. Priority Date: 11/27/1998
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Takagi, Yoshiaki
• Primary Examiner(s): Dorvil, Richemond
• Assistant Examiner(s): Nolan, Daniel A.
• Application Number:
  US09/426,751
• Time in Patent Office: 770 Days
• Field of Search: 704/232, 704/201, 704/205, 704/211, 704/234, 704/230, 704/270
• US Class Current: 704/230
• CPC Class Codes: G10L 19/0208 Subband vocoders
• CPC Class Codes: H04B 1/667 using a division in frequency subbands for TV signals H04N19/63

Abstract

In a audio signal coding apparatus, a band separating filter separates a digital audio signal into M bands of audio data. A quantizing circuit quantizes M bands of the audio data. A data grouping circuit groups M bands of the audio data to output N bands of the audio data in accordance with frequency resolution of the human being. M and N being natural numbers more than one, M>N. In an audio signal decoding apparatus, a receiving circuit receives the bit stream including audio data which are grouped into N bands from M bands of audio data which is generated from an audio signal A coded data separating circuit separates N bands of audio data to M bands of the audio data. A de-quantizing circuit for de-quantizes M bands of the audio data. A combining circuit combines M bands of the audio data into an output audio signal. A wireless microphone system using the audio signal coding apparatus and the audio signal decoding apparatus is also disclosed. A method of coding audio data and a method of decoding the audio data are also disclosed.

Claims

1. A wireless microphone comprising:

a microphone for receiving a sound to generate a sound signal;

an aid converter for a/d-converting said sound signal into audio data;

compressing means for compressing said audio data in accordance with frequency resolution of the human being to generate compressed audio data, said compressing means including;

band separating means for separating said audio data into M bands of audio data;

quantizing means for quantizing M bands of said audio data, and

data grouping means for grouping M bands of said audio data to output N bands of said audio data as said compressed audio data in accordance with frequency resolution of the human being, M and N being natural numbers more than one, M>

N; and

transmitting means for transmitting said compressed audio data, wherein said M and N bands each include the same amount of data.

2. A wireless microphone comprising:

a microphone for receiving a sound to generate a sound signal;

an a/d converter for a/d-converting said sound signal into audio data;

band separating means for separating said audio data into M bands of audio data;

bit assignment determining means for determining bit assignment and generating M bands of bit assignment data in accordance with M bands of said audio data, respectively;

magnification determining means for detecting M bands of maximum levels of M bands of said audio data and determining M bands of magnification data in accordance with M bands of said maximum levels, respectively;

data grouping means for grouping M bands of said magnifications into N bands of said magnification data and grouping M bands of said bit assignment data into N bands of said assignment data to output N bands of said magnification data and N bands of said assignment data;

combining means for combining M bands of said audio data into N bands of audio data;

normalizing means for normalizing N bands of said audio data from said band separating means in accordance with N bands of said magnification data; and

quantizing means for quantizing N bands of said audio data in accordance with N bands of said bit assignment data to output said quantized N bands of said audio data, M and N being natural numbers more than one, M>

N.

3. A wireless microphone comprising:

a microphone for receiving a sound to generate a sound signal;

an a/d converter for a/d-converting said sound signal into an audio data;

band separating means for separating a digital audio signal into M bands of audio data;

magnification determining means for detecting M bands of maximum levels of M bands of said audio data and determining M bands of magnification data in accordance with M band of said maximum levels, respectively;

normalizing means for normalizing M bands of said audio data from said band separating means in accordance with M bands of magnification data, respectively;

bit assignment determining means for determining bit assignment and generating M bands of bit assignment data in accordance with M bands of said audio data, respectively;

quantizing means for quantizing M bands of said audio data in accordance with M bands of said bit assignment data to output M bands of said quantized audio data, respectively; and

data grouping means for grouping M bands of said magnification data into N bands of magnification data and grouping M bands of said bit assignment data into N bands of assignment data to output N bands of said magnification data and N bands of said assignment data, M and N being natural numbers more than one, M>

N.