Audio signal storing apparatus having a function for converting speech speed

• US 5,717,818 A
• Filed: 09/09/1994
• Issued: 02/10/1998
• Est. Priority Date: 08/18/1992
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Morikawa, Juichi, Takamiya, Tadashi, Nejime, Yoshito, Hataoka, Nobuo, Kumagai, Yukio, Kawauchi, Yasunori
• Primary Examiner(s): Tung, Kee M.
• Application Number:
  US08/301,994
• Time in Patent Office: 1,250 Days
• Field of Search: 395/2.2, 395/2.23, 395/2.24, 395/2.17, 395/2.67, 395/2.8, 395/2.76, 395/2.87, 395/2.16, 381/34-40, 381/51, 381/68.2, 381/68, 381/23.1, 381/68.4
• US Class Current: 704/211
• CPC Class Codes: G10L 21/04 Time compression or expansion
• CPC Class Codes: H04R 1/005 using digitally weighted transducing elements
• CPC Class Codes: H04R 25/70 Adaptation of deaf aid to hearing loss, e.g. initial electronic fitting

Abstract

The speed of an input speech is changed without any change of the pitch of the input speech. Raw data of a speech are stored so that the speed of the speech can be modulated continuously on the basis of the raw data of the speech. In the speech speed conversion method, a speech speed conversion process for the input speech is carried out in a period designated when speech speed conversion is needed, which the speech speed conversion is not carried out in the other period. Further, in the speech speed conversion apparatus having a unit for inputting a speech, a speech speed conversion unit for changing the speed of the input speech, and a unit for supplying the output of the speech speed conversion unit as an output speech to listener'"'"'s ears, the apparatus further includes a speech speed conversion switch, and a unit for outputting a speech while changing the speech speed of the input speech in a period in which the speech speed conversion switch is turned on, but for outputting a speech without any change of the input speech in the other period in which the speech speed conversion switch is turned off.

Claims

1. An audio signal storing apparatus having a function for converting speech speed, comprising:

audio signal input means for taking in an audio signal;

a memory for storing said audio signal;

an audio signal processing means for executing one of the following processing modes;

a through mode for storing the audio signal into said memory while the audio signal is read out from said memory without changing the audio signal speed,

a repeat mode for reading out the audio signal stored in said memory in the past and for outputting the past audio signal read out from said memory without changing the audio signal speed, and

a speech speed changing mode for executing a speech speed changing process for the audio signal read out from said memory;

switch means for causing said audio signal processing means to execute as said speech speed changing process one of said three processing modes of said audio signal processing means; and

output means for outputting an output of said audio signal processing means as an audio signal.

2. An apparatus according to claim 1, further comprising:

means for controlling at least an audio signal derived from an audio/video apparatus coupled to said audio signal storing apparatus.

3. An apparatus according to claim 1, wherein, when said repeat mode is selected by said switch means, said audio signal is read out from a position where the audio signal had been recorded in the past by a predetermined time and outputted the read out audio signal.

4. An apparatus according to claim 1, wherein there are at least two speech speeds of an output audio signal in said repeat mode among a speed same as the input speed, a slow speed lower than the input speed, a fast speed higher than the input speed, and a gradually accelerated speed.

5. An apparatus according to claim 1, further comprising:

a catch-up mode for adjusting a quantity of a time lag from the input audio signal in real time so as to catch up with the real time audio signal when the time lag is caused by the repeat mode or the speech speed changing mode.

6. An apparatus according to claim 5, wherein said catch-up mode starts during execution of said repeat mode or said speech speed changing mode, and is changed to said through mode when the output audio signal catches up to the real time input audio signal.

7. An apparatus according to claim 6, wherein a message signal is outputted when the output audio signal catches up to the real time input audio signal.

8. An apparatus according to claim 5, wherein each of said means forming said apparatus is disposed on a surface of a body of said apparatus or at an inside location of said body, said apparatus has, as said switch means, a repeat switch for instructing said repeat mode, a speech speed change mode switch for instructing said speech speed change mode, and a reset switch for cancelling speech speed change mode and transferring to said through mode, said switches being disposed at a easy-to-use place on a periphery of a side of said body.

9. An apparatus according to claim 8, wherein said audio signal input means is disposed on a top portion of said body so as to prevent said audio signal input means from directly touching clothes when said apparatus body is put into a pocket while in use.

10. An apparatus according to claim 5, wherein, when said reset switch is turned on during said catch-up mode, the catch up mode is transferred to said through mode.

11. An apparatus according to claim 5, wherein said catchup mode is started during execution of said repeat mode or said speech speed changing mode, and is transferred to said through mode when the audio signal is reproduced by the repeat mode indication time point.

12. An apparatus according to claim 1, further comprising:

means for hearing said audio signal from said output means through a binaural headphone.

13. An apparatus according to claim 1, wherein each of said switches is formed with a switch which has a feeling of soft touch so that said audio signal input means does not pick up a click noise of the switch.

14. An apparatus according to claim 1, wherein each of said means forming said apparatus are disposed on a surface of a body of said apparatus or at an inside location of said body, and said apparatus further comprises a rustling prevention means for preventing said audio signal input means from directly touching clothes when said apparatus body is put into a pocket while in use.

15. An apparatus according to claim 1, wherein each of said means forming said apparatus is disposed on a surface of a body of said apparatus or at an inside location of said body, and said apparatus further comprises a display means which is provided at a predetermined position of said apparatus to thereby visually indicate a quantity of time lag from the real time produced by execution of said repeat mode or said speech speed changing mode.

16. An apparatus according to claim 15, wherein a ring buffer is used as said memory means, and said apparatus further comprises means for managing a lag time by a counter which indicates a time lag on said ring counter, a result of said managing means being displayed by said display means.

17. An apparatus according to claim 1, wherein said audio signal processing means further executes a standby mode, wherein a clock cycle for executing the process is decreased and the same process as in the through mode is executed.

18. An apparatus according to claim 1, further comprising:

an electric source switch of an apparatus body operated at three stages consisting of an ON stage, and OFF stage and an ON-OFF intermediate stage, and

an electric power supply means operated in an analog through mode in which analog input-output systems are short-circuited so as to be directly connected to each other to thereby stop electric power supply to a digital processing system between said analog input-output systems when said electric source switch is in the intermediate stage.

19. A telephone line switching system having said speech speed changing means as defined in claim 1.

20. An apparatus according to claim 1, wherein, in said through mode, the audio signal read out from said memory is outputted without changing not only the audio signal speed but also other characteristics of said audio signal.

21. An apparatus according to claim 1, wherein said audio signal processing means is controlled in such a manner that an intermittent sound is outputted until the audio signal stored in said memory in the past is read out from said repeat mode selected by said switch means.

22. An apparatus according to claim 1, wherein each of said means forming said apparatus is disposed on a surface of a body of said apparatus or at an inside of said body, said apparatus has, as said switch means, a repeat switch for instructing said repeat mode, a speech speed change mode switch for instructing said speech speed change mode, and a reset switch for cancelling said speech speed change mode and for transferring to said through mode, said switches being disposed at a easy-to-use place on a periphery of a side of said body.

23. An apparatus according to claim 22, wherein said switches have respective surface forms different in tactility so as to be identified without seeing.

24. An audio signal storing apparatus having a function for converting speech speed, comprising:

a microphone for converting an acoustic signal into an electric signal;

a first analog amplifier for amplifying an output of said microphone;

a first low-pass filter for removing high-frequency components from an output of said analog amplifier;

an A/D converter for converting an output of said analog amplifier into a digital signal;

a memory means for storing input speech data and data obtained as a result of signal processing;

a digital signal processor for reading out data from said memory means and for carrying out digital signal processing to execute a speech speed changing process for the acoustic signal in accordance with an external speech speed conversion instruction;

means for controlling said speech speed changing process executed by said digital signal processor;

means for changing a parameter of said speech speed changing process;

selecting means for receiving said speech speed conversion instruction and causing said digital signal processor to execute as said speech speed changing process one of the following processings;

a first processing for storing input speech data into said memory means while the speech data are read out from said memory means, and for outputting the speech data read out from said memory means without changing the speech speed,

a second processing for reading out the speech data stored in said memory means in the past and for outputting the past speech data read out from said memory means without changing the speech speed, and

a third processing for executing said speech speed changing process for the speech data read out from said memory means;

a D/A converter for converting digital speech data outputted from said digital signal processor into an analog speech signal;

a second low-pass filter for removing high-frequency components from outputs of said D/A converter;

a second analog amplifier for amplifying an output of said second low-pass filter; and

a head-phone for converting an output of said second analog amplifier into an acoustic signal and for supplying the acoustic signal to ears of a user.

25. An apparatus according to claim 24, wherein said third processing is provided as a software executed by said digital signal processor having an input terminal for receiving an interruption request signal from the outside, so that an instruction for selection of one mode among said first to third processings by said selecting means is provided to said digital signal processor via the input terminal receiving said interruption request.

26. An audio signal storing apparatus having a function for converting speech speed, comprising:

audio signal input means for taking in an audio signal;

a ring buffer for storing said audio signal;

an audio signal processing means for executing one of the following processing modes;

a through mode for storing audio signal into said ring buffer while the audio signal is read out from said ring buffer and for outputting the audio signal read our from said ring buffer without changing the audio signal speed,

a repeat mode for reading out the audio signal stored in said ring buffer in the past and for outputting the past audio signal read our from said ring buffer without changing the audio signal speed, and

a speech speed changing mode for executing a speech speed changing process for the audio signal read out from said ring buffer;

wherein, in said speech speed changing mode, average power of said audio signal is calculated in each input frame unit, said speech speed changing process being executed only in a case where said average power is higher than a predetermined threshold value, and the audio signal of frame unit being directly outputted in a case where said average power is lower than said predetermined threshold value,

said speech speed changing mode being executed as a pipeline process by each frame unit with use of a plurality of input frame buffers in such a manner that for data of every frame a pitch extraction process is applied to a leading portion of the frame to detect a pitch of the leading portion, data of a length of one pitch thus detected is transferred to output buffers, data of a length of two pitches is multiplied by a window function which changes from 0 to 1 and by a window function which changes from 1 to 0, respective data obtained by the multiplications by the window functions are added together to thereby generate a reproduced wave pattern having a time length of two pitches, the reproduced wave pattern being inserted in the rear of the preliminary transferred data of the length of one pitch, a pitch detection process is again carried out while spearheaded by a position preliminary subjected to the pitch extraction process to thereby perform pitch detection at said position, and data of the length of n pitches (n is an integer) based on the pitch length obtained by the final pitch detection to the output buffers;

a switch for causing said audio signal processing means to execute as said speech speed changing process one of said processing modes of the audio signal processing means; and

output means for outputting an output of said audio signal processing means as an audio signal.

27. An apparatus according to claim 26, wherein said ring buffer stores the audio signal by each frame unit.

28. An apparatus according to claim 26, wherein determining of waveform expansion/reduction processes in said speech speed changing process is made by referring to results of comparison between power of frame and a threshold value which is externally adjustable.

29. An apparatus according to claim 26, wherein a second threshold value is provided in the comparison process for comparing said average power with the predetermined threshold value so that when a frame having lower average power than said second threshold value is continued for a longer time than a predetermined time threshold, data in the frame having lower average power than the second threshold value and continued for a longer time than said time threshold are forbidden to be transferred to the output buffers.

30. A speech speed conversion apparatus for receiving an input speech and for changing output time without changing a pitch of said input speech, comprising:

a portable case having a speech input microphone disposed on a surface of the case, an output control switch, and a speech output terminal, said case being as small as a palm;

said case includes;

compressing means coupled to said input microphone for digitally compressing said input speech in each predetermined length, said compressing of the input speech being deleting of data bit, wherein a speech power is smaller than a first threshold value and the period is longer than a predetermined time length,

a memory for storing the compressed speech data in an order of time series,

decompressing means for reading out the compressed speech data of the predetermined length from said memory and for releasing said compressed speech data from the compression,

speech speed converting means for outputting the decoded speech data in response to an instruction from said output control switch and for converting the speed of said speech data in such a manner that the decompressed speech data, in a period where the power of speech data is larger than a second threshold value, is maintained in constant pitch and the time axis is extended longer than the input time of said period; and

output means for supplying an output from said speech speed converting means to said speech output terminal.

31. An audio signal storing apparatus having a function for converting speech speed, comprising:

audio signal input means for taking in an audio signal;

a memory for digitizing said audio signal and storing the digitized audio signal in accordance with a writing pointer;

an audio signal processing means for executing one of the following processing modes for the audio signal read out from a reading pointer position of said memory;

a through mode for outputting a read-out audio signal from said memory in such a manner that a reading pointer position is same as a writing pointer position,

a repeat mode for outputting the audio signal read out from said memory by setting the reading pointer position which is returned back by a predetermined time from the writing pointer, and

a speech speed changing mode for outputting the audio signal by executing a speech speed changing process for the audio signal read out from said memory in such a manner that the reading pointer position is gradually delayed from the writing pointer;

switch for causing said audio signal processing means to execute as said speech speed changing process one of said three processing modes of said audio signal processing means; and

output means for converting the output of said audio signal processing means to an analog signal and outputting said analog signal as an audio signal.

32. An apparatus according to claim 31, wherein the reading pointer position and the writing pointer position are same with each other at a start point of said speech speed changing mode.

33. An apparatus according to claim 31, wherein the reading pointer position is delayed in time from the writing pointer position at a start point of said speech speed changing mode.

34. An apparatus according to claim 31, wherein a time span between the reading pointer position and the writing pointer position is constant in said repeat mode.