Methods of efficiently recording and reproducing an audio signal in a memory using hierarchical encoding
First Claim
1. An apparatus for recording a signal in a memory and for reproducing the signal, comprising:
- an analog-to-digital converter for converting said signal to first digitized data;
a hierarchical encoder, for encoding said first digitized data to generate a plurality of successive hierarchical levels of data corresponding to the data including a lowest hierarchical level of data for reproduction of the signal with relatively low fidelity, and including at least one other higher hierarchical level of data, each successive higher hierarchical level representing additional data for successively relatively greater fidelity, and for writing said hierarchical levels of data into said memory;
a memory address generator coupled to said hierarchical encoder, for generating memory addresses so that, upon determining that said memory has reached maximum storage capacity, recording can continue by overwriting a highest hierarchical level of data previously recorded in said memory with new data of hierarchical levels lower than the overwritten highest hierarchical level;
a hierarchy code generator coupled to said memory address generator, for recording in said memory, a code indicative of a number of hierarchical levels of data currently recorded therein;
a hierarchy code reader coupled to said memory, for reading said recorded code;
a hierarchical decoder coupled to said memory, for reading a number of hierarchical levels of data designated by said code and for decoding the read data to generate second digitized data; and
a digital-to-analog converter coupled to receive said second digitized data from said hierarchical decoder, for converting said second digitized data to a signal.
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Abstract
An audio signal is recorded in a semiconductor memory in a plurality of hierarchical levels, with the lowest level sufficing for reproduction with a certain reduced degree of fidelity. Successfully higher hierarchical levels provide successively greater fidelity when reproduced. When the memory has been determined to have reached maximum capacity, recording continues by overwriting the highest hierarchical level of data currently stored in the memory with lower hierarchical levels of new data. A code is recorded in the memory, indicating the number of hierarchical levels recorded therein, for subsequent reproduction. The audio signal can furthermore be recorded in variable-length frames and reproduced at high speed by reading every N-th frame, N being a positive integer, or by reading only frames having at least a certain minimum length.
102 Citations
17 Claims
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1. An apparatus for recording a signal in a memory and for reproducing the signal, comprising:
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an analog-to-digital converter for converting said signal to first digitized data; a hierarchical encoder, for encoding said first digitized data to generate a plurality of successive hierarchical levels of data corresponding to the data including a lowest hierarchical level of data for reproduction of the signal with relatively low fidelity, and including at least one other higher hierarchical level of data, each successive higher hierarchical level representing additional data for successively relatively greater fidelity, and for writing said hierarchical levels of data into said memory; a memory address generator coupled to said hierarchical encoder, for generating memory addresses so that, upon determining that said memory has reached maximum storage capacity, recording can continue by overwriting a highest hierarchical level of data previously recorded in said memory with new data of hierarchical levels lower than the overwritten highest hierarchical level; a hierarchy code generator coupled to said memory address generator, for recording in said memory, a code indicative of a number of hierarchical levels of data currently recorded therein; a hierarchy code reader coupled to said memory, for reading said recorded code; a hierarchical decoder coupled to said memory, for reading a number of hierarchical levels of data designated by said code and for decoding the read data to generate second digitized data; and a digital-to-analog converter coupled to receive said second digitized data from said hierarchical decoder, for converting said second digitized data to a signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for recording a signal in a memory, comprising:
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an analog-to-digital converter for converting said signal to digitized data; a hierarchical encoder, for encoding said digitized data to generate a plurality of successive hierarchical levels of data corresponding to the signal including a lowest hierarchical level of data for reproduction of the signal with relatively low fidelity, and including at least one other higher hierarchical level of data, each successive higher hierarchical level representing additional data for successively relatively greater fidelity; a buffer memory coupled to said hierarchical encoder, for storing the hierarchical levels of data generated by said hierarchical encoder; a memory address generator coupled to said buffer memory, for generating memory addresses at which said hierarchical levels of data are stored; a data size calculator coupled to said memory address generator, for calculating an amount of data stored in said buffer memory; a hierarchical level selector coupled to said data size calculator, for determining a number of hierarchical levels of data capable of being stored in said memory, and for copying the number of hierarchical levels of data thus determined from said buffer memory to said memory; and a hierarchy code generator coupled to said hierarchical level selector, for recording in said memory a code indicative of a number of hierarchical levels of data recorded therein. - View Dependent Claims (8, 9, 10)
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11. An apparatus for recording data in a memory, comprising:
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an encoder for encoding the data by generating a plurality of successive hierarchical levels of data corresponding to the signal including a first hierarchical level of data representing data reproducible at a relatively low fidelity and including at least one other hierarchical level of data higher than the first hierarchical level, each successively higher hierarchical level of data representing data reproducible at a successively relatively greater fidelity; and a controller for controlling said encoder to record said hierarchical levels of encoded data in the memory and, upon determining that the memory has reached maximum storage capacity, for controlling the encoder to overwrite a highest hierarchical level of previously recorded encoded data in the memory with new encoded data of hierarchical levels lower than the previously recorded highest hierarchical level of encoded data. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification