EP0421259A2
Expired / Lapsed
EP
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Digital signal encoding apparatus
Assignee: Sony Corp
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Filing: 1990-09-26
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Granted: —
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Expires: 2010-09-26
Abstract
Abstract The invention provides a digital signal encoding apparatus in which input digital signals are divided (13) into a plurality of frequency bands so that the bandwidth of each frequency band will be the higher the higher the frequency band, the allowable noise level is set for each frequency band on the basis of the energy value (14) of each frequency band, and components of each frequency band are quantized (24) with the number of bits consistent with the level difference between the energy of each frequency band and the preset allowable noise level. The output information volume following the quantization (24) is detected and the number of bits of allocation for quantization is corrected (28, 29; 27, 31) in dependence upon the error between the detection output and a target value (3) to render the information volume constant over a predetermined time period to enable bit rate adjustment or bit packing with lesser signal deterioration by a simplified construction.
Inventors
- 👤 Masayuki Nishiguchi
- 👤 Yoshihito Fujiwara
- 👤 Tomoko Umezawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 05:16
CPC Classifications
H; H03; H03M; H03M7/00; H04; H04B; H04B1/00; H04B1/66; H04B1/665
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
143 words
A digital signal encoding apparatus comprising noise level setting means (13-22) for dividing input digital signals into a plurality of frequency bands so that the bandwidth of each frequency band will be the broader the higher the frequency band, said noise level setting means setting the allowable noise level of each frequency band on the basis of the energy of each frequency band, and quantization means (24) for quantizing components of each frequency band with a number of bits consistent with the level difference between the energy of each frequency band and that of the output of said level setting means, wherein the improvement resides in that the volume of an output information of said quantization means (24) is detected (25-28) and the volume of information over a predetermined time interval is made constant (16, 29) as a function of the detection output.
Claim 2
Dependent Claim
143 words
A digital signal encoding apparatus comprising noise level setting means (13-22) for dividing input digital signals into a plurality of frequency bands so that the bandwidth of each frequency band will be the broader the higher the frequency band, said noise level setting means setting the allowable noise level of each frequency band on the basis of the energy of each frequency band, and quantization means (24) for quantizing components of each frequency band with a number of bits consistent with the level difference between the energy of each frequency band and that of the output of said level setting means, wherein the improvement resides in that the volume of an output information of said quantization means (24) is detected (25-28) and the volume of information over a predetermined time interval is made constant (16, 29) as a function of the detection output.
Claim 3
Dependent Claim
69 words
The signal encoding apparatus according to claim 1, wherein said noise level setting means includes noise level computing means (14, 15, 17) for computing the allowable noise level for each frequency band, minimum audible curve setting means (22) for setting a minimum audible curve in dependence upon the frequency, and synthesis means (18) for synthesizing outputs of said noise level computing means and said minimum audible curve setting means.
Claim 4
Dependent Claim
54 words
The signal encoding apparatus according to claim 1 or 2, wherein the volume of output information of said quantization means (24) is detected and said noise level computing means (14, 15, 16, 17) is controlled as a function of the detection output to render the volume of information constant over a predetermined time interval
Claim 5
Dependent Claim
62 words
The signal encoding apparatus according to anyone of claims 1 to 3, wherein the number of bits of allocation of said quantization means (24) is corrected (28, 29) in dependence upon an error between a target value (3) and the detection output of output information volume of said quantization means (24) to render the information volume constant over a predetermined time interval.
Claim 6
Dependent Claim
70 words
The signal encoding apparatus according to anyone of claims 1 to 3, wherein the number of bits of allocation of said quantization means is corrected (31) on the basis of an error between a target value (3) and the detection output of output information volume of said quantization means (24) and the energy of each frequency band (14, 33, 39) to render the information volume over a predetermired time interval.
Claim 7
Dependent Claim
138 words
A digital signal encoding apparatus comprising noise level setting means (13-22) for dividing input digital signals into a plurality of frequency bands so that the bandwidth of each frequency band will be the broader the higher the frequency band, said noise level setting means setting the allowable noise level of each frequency band on the basis of the energy of each frequency band, and quantization means (24) for quantizing components of each frequency band with a number of bits consistent with the level difference between the energy of each frequency band and that of the output of said level setting means, wherein the improvement resides in that said noise level setting means (13-22) are adapted for setting the allowable noise level so as to be higher for the same energy level towards the side of a higher frequency.
Claim 8
Dependent Claim
138 words
A digital signal encoding apparatus comprising noise level setting means (13-22) for dividing input digital signals into a plurality of frequency bands so that the bandwidth of each frequency band will be the broader the higher the frequency band, said noise level setting means setting the allowable noise level of each frequency band on the basis of the energy of each frequency band, and quantization means (24) for quantizing components of each frequency band with a number of bits consistent with the level difference between the energy of each frequency band and that of the output of said level setting means, wherein the improvement resides in that said noise level setting means (13-22) are adapted for setting the allowable noise level so as to be higher for the same energy level towards the side of a higher frequency.
References Cited (Backward Citations)
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