Method of recording and reading audio information signals in digital form, and apparatus for performing same

• US 4,916,742 A
• Filed: 12/18/1987
• Issued: 04/10/1990
• Est. Priority Date: 04/24/1986
• Status: Expired due to Fees

• Current Assignee: Vsesojuzny Nauchno-Issledovatelsky Institut Radio-Veschatelnogo Priema I Akustiki Imeni Aspopova
• Original Assignee: Vsesojuzny Nauchno-Issledovatelsky Institut Radio-Veschatelnogo Priema I Akustiki Imeni Aspopova
• Inventors: Kolesnikov, Viktor M., Brailovsky, Gennady S., Bank, Mikhail U., Prygun, Viktor I., Lazer, Ilya M.
• Primary Examiner(s): Clark, David L.
• Assistant Examiner(s): Knepper, David D.
• Application Number:
  US07/171,007
• Time in Patent Office: 844 Days
• Field of Search: 381/29-35, 364/513.5, 369/25, 369/50
• US Class Current: 704/215
• CPC Class Codes: G11B 20/00007 Time or data compression or expansion audio compression based on psychoacoustics G10L19/00; data processing for reproducing audio data at different playback speeds G10L21/04; video compression H04N19/00; data compression per se H03M7/30
• CPC Class Codes: G11B 27/3027 used signal is digitally coded
• CPC Class Codes: H03M 7/30 Compression speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
• CPC Class Codes: H04B 14/046 Systems or methods for reducing noise or bandwidth

Abstract

The method of recording and reading audio information signals in digital form includes detecting, during time compression of digital signals, a chain of code values of the digital signal corresponding to a pause in the audio signal, measuring the duration of this chain of code values of the digital signal and shaping a pause identifier code and a pause duration code for subsequent recording with the digital signal. Furthermore, in the reading mode, time decompression of the digital signal includes detecting the pause identifier code and the pause duration code and using them to restore the duration of said chain of code values of the digital signal. To perform this method, the apparatus comprises a pause decoder (17), a pause identifier code shaper (18), a pause identifier code decoder (19), a condition (20) of pause duration count control signals and a pause duration counter (21).

Claims

1. A method of recording and reading audio information signals in digital form, comprising the steps of:

comparing the code values of the digital signal with a predetermined pause identifier code;

distorting the code value of the digital signal by altering one of the minor symbols of the code value of the digital signal if the result of the comparison coincides;

detecting a chain of code values corresponding to a pause in an audio signal;

measuring the duration of the chain of code values of the digital signal corresponding to the pause in the audio signal;

compressing the digital signal, which is performed by generating a pause identifier code and a pause duration code for their subsequent recording with the digital signal;

reading out of the digital signal;

detecting the pause identifier code and the pause duration code by which the time decompression is performed and using them for restoring the duration of the chain of code values of the digital signal corresponding to the pause in the audio signal.

2. A method of recording and reading audio information signals in digital form as claimed in claim 1 which includes converting a pause duration code into another pause duration code corresponding to a predetermined reproduction tempo.

3. A method of recording and reading audio information signals in digital form as claimed in claim 2, in which the conversion of a pause duration code into another predetermined pause duration code corresponding to a predetermined reproduction tempo is effected during reading out.

4. A method of recording and reading audio information signals in digital form, as claimed in claim 1 wherein, in case of occurrence in the digital signals of two successive pauses, recording of the duration code of the preceding pause is followed by the recording to the identifier code of the successive pause not earlier than after a time interval corresponding to the maximum duration of the pause code,

during reading out, prior to time decompression of the digital signals, the generation of the first pause is allowed only if its identifier code appears not earlier than after a time interval corresponding to the maximum duration of the pause duration code from the moment of the beginning of the reading out of the audio signal,

and if a pause identifier code appears during this time, the decoding of this pause identifier code is inhibited, and a new count of the time interval corresponding to the maximum duration of the pause duration code is initiated.

5. A method of recording and reading audio information signals in digital form as claimed in claim 4 which includes converting a pause duration code into another pause duration code corresponding to a predetermined reproduction tempo.

6. A method of recording and reading audio information signals in digital form as claimed in claim 5 in which the conversion of a pause duration code into another predetermined pause duration code corresponding to a predetermined reproduction tempo is effected during reading out.

7. A method of recording and reading audio information signals in digital form as claimed in any one of claims 1 to 4, which includes converting a pause duration code into another pause duration code corresponding to a predetermined reproduction tempo.

8. A method of recording and reading audio information signals in digital form as claimed in claim 7, in which the conversion of a pause duration code into another predetermined pause duration code corresponding to a predetermined reproduction tempo is effected during reading out.

9. An apparatus for recording and reading audio information signals in digital form, comprising a series connection of a data input unit, a storage and a data output unit, the data input unit having main data inputs and outputs, the control inputs, respectively, of the data input unit and of the data output unit and the timing input of the storage having connected thereto the corresponding outputs of the control unit, the main control inputs of the control unit and the main data outputs of the data output unit being, respectively, the "timing", "record", "stop" and "playback" control inputs and the data outputs of the apparatus also having data inputs;

a series connection of a pause decoder and a pause identifier code shaper; and

a series connection of a main pause identifier code decoder, a conditioner of pause duration count control signals and a pause duration counter, the additional data outputs of the data input unit being connected to the respective inputs of the pause decoder, and the outputs of the pause identifier code shaper and of the pause duration counter being connected, respectively to the corresponding additional data inputs of the data input unit, the additional data outputs of the data output unit being connected to the corresponding inputs of the main pause identifier code decoder, the outputs of the storage being additionally connected to the corresponding inputs of the conditioner of pause duration count control signals, the output of the pause decoder being additionally connected to an additional input of the control unit and to the corresponding input of the conditioner of pause duration count control signals having connected to one of the control inputs thereof an output "P" of the pause duration counter, other control inputs being "timing", "record" and "playback" control inputs of the apparatus, additional control inputs of the control unit (10) being connected to the corresponding outputs of the conditioner of pause duration count control signals, an input "C" of the pause duration counter and the corresponding inputs of the pause identifier code shaper being the "timing" and "record" control inputs of the apparatus;

a series connection of an audio signal code corrector and an additional pause identifier code decoder, the data inputs of the corrector being the data inputs of the apparatus, the outputs of the audio signal code corrector being connected to the corresponding data inputs of the data input unit, the inputs of the additional pause identifer code decoder being connected to additional data outputs of the data input unit, and the output thereof being connected to the control input of the audio signal code corrector.

10. An apparatus for recording and reading audio information signals in digital form as claimed in claim 9 which comprises a series connection of a reproduction tempo counter and an additional switching unit having its output connected to the input "C" of the pause duration counter, the respective control inputs of the additional switching unit being the "record", "playback", and "timing" control inputs of the apparatus, and other inputs of this additional switching unit being the "normal", "tempo `p` variation" and "tempo `n` variation" control inputs of the apparatus, the reproduction tempo counter having a count input "C".

11. An apparatus for recording and reading audio information signals in digital form as claimed in claim 10, in which the input "C" of the reproduction tempo counter is the "timing" control input of the apparatus.

12. An apparatus for recording and reading audio information signals in digital form as claimed in claim 10, which comprises a frequency generator having its output connected to the input "C" of the reproduction tempo counter.

13. An apparatus for recording and reading audio information signals in digital form as claimed in claim 9, which comprises a counter of binary words of the pause duration code;

a main switching unit;

a conditioner of a signal of binary words of the pause duration code;

a conditioner of a reset signal for the counter of binary words of the pause duration code and two AND gates, the outputs of the counter of binary words of the pause duration code being connected to other additional data inputs of the data input unit and to the corresponding inputs of the conditioner of pause duration count control signals, first inputs of the main switching unit being connected, respectively, with the outputs of the pause decoder and of the main pause identifer code decoder, and second inputs of the main switching unit being, respectively, the "timing" and "playback" control inputs of the apparatus, the output of the main switching unit being connected, respectively, with the first input of the conditioner of a signal of binary words of the pause duration code and with the input of the conditioner of a reset signal for the counter of binary words of the pause duration code, having their respective outputs connected with the input "C" and input "R" of the counter of binary words of the pause duration code, having its output "P" connected to the second input of the conditioner of a signal of binary words of the pause duration code, of which the third input is connected with one of the outputs of the control unit and with the first inputs of the respective AND gates, the second input (79) of the first AND gate being connected with the output of the pause decoder and the output of this AND gate being connected to the corresponding inputs of the pause identifier code shaper, of the control unit and of the conditioner of pause duration count control signals, the other input of the second AND gate being connected to one of the outputs of the control unit, and the output of this AND gate being connected to the control input of the data output unit.

14. An apparatus for recording and reading audio information signals in digital form as claimed in claim 13, which comprises a series connection of a reproduction tempo counter and an additional switching unit having its output connected to the input "C" of the pause duration counter, the respective control inputs of the additional switching unit being the "record", "playback", and "timing" control inputs of the apparatus, and other inputs of this additional switching unit being the "normal", "tempo `p` variation" and "tempo `n` variation" control inputs of the apparatus, the reproduction tempo counter having a count input "C".

15. An apparatus for recording and reading audio information signals in digital form as claimed in claim 14, in which the input "C" of the reproduction tempo counter is the "timing" control input of the apparatus.

16. An apparatus for recording and reading audio information signals in digital form as claimed in claim 14, which comprises a frequency generator having its output connected to the input "C" fo the reproduction tempo counter.

17. An apparatus for recording and reading audio information signals in digital form as claimed in either of the claim 9 or 13 which comprises a series connection of a reproduction tempo counter and an additional switching unit having its output connected to the input "C" of the pause duration counter, the respective control inputs of the additional switching unit being the "record", "playback", and "timing" control inputs of the apparatus, and other inputs of this additional switching unit being the "normal", "tempo `p` variation" and "tempo `n` variation" control inputs of the apparatus, the reproduction tempo counter having a count input "C".

18. An apparatus for recording and reading audio information signals in digital form as claimed in claim 17, in which the input "C" of the reproduction tempo counter is the "timing" control input of the apparatus.

19. An apparatus for recording and reading audio information signals in digital form as claimed in claim 17, which comprises a frequency generator having its output connected to the input "C" of the reproduction tempo counter.