Signal processing apparatus and mobile radio communication terminal

• US 20010041976A1
• Filed: 05/10/2001
• Published: 11/15/2001
• Est. Priority Date: 05/10/2000
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Miseki, Kimio, Taniguchi, Takayuki, Tsukahara, Yuriko
• Application Number:
  US09/852,235
• Publication Number:
  US 20010041976A1
• Time in Patent Office: Days
• US Class Current: 704/226
• CPC Class Codes: G10L 19/18 Vocoders using multiple modes
• CPC Class Codes: G10L 21/0208 Noise filtering

Abstract

In a signal processing apparatus, a speech coder includes, as three sections for coding speech data by different algorithm, an Algorithm-A coding section, an Algorithm-B coding section and an Algorithm-C coding section. A noise suppressor includes, as three sections for suppressing background noise by different algorithm, an Algorithm-X noise suppress section, an Algorithm-Y noise suppress section and an Algorithm-Z noise suppress section. A suppress algorithm switching control section controls switching on the basis of information from a coding algorithm switching control section such that an optimal one of the noise suppress sections may function in association with the coding section activated in the speech coder.

Claims

1. A signal processing apparatus comprising:

a noise suppressor having a plurality of different noise suppression characteristics, suppressing background noise contained in a speech signal;

a speech encoder having a plurality of different coding algorithm, encoding the suppressed speech signal by using one of said different coding algorithm; and

wherein said noise suppressor selects one noise suppression characteristic in accordance with the used coding algorithm at the speech encoder.

6. The signal processing apparatus according to

claim 1

, wherein the noise suppressor comprising a parameter setting means for setting a parameter so as to select an optimal noise suppression characteristic, sand parameters varies the noise suppression characteristics.

7. The signal processing apparatus according to

claim 1

, wherein said parameters are set in accordance with the used coding algorithm at the speech encoder.

2. A signal processing apparatus comprising:

a noise suppressor having a plurality of different noise suppression characteristics, suppressing background noise contained in a speech signal;

a speech encoder having a plurality of different coding rates, encoding the suppressed speech signal by using one of said different coding rates; and

wherein said noise suppressor selects one noise suppression characteristic in accordance with the used coding rate at the speech encoder.

3. The signal processing apparatus according to

claim 2

, wherein the noise suppressor comprising a frequency divider dividing the speech signal into several speech signals, each of the speech signals having a different frequency band, said noise suppressor only suppressing background noise contained in the speech signal having a predetermined frequency band if the speech encoder selects a predetermined coding rate for encoding the speech signal.

4. The signal processing apparatus according to

claim 2

, wherein the noise suppressor comprising a frequency divider dividing the speech signal into several speech signals, each of the speech signals having a different frequency band, said noise suppressor stops suppressing background noise contained in the speech signal having a predetermined frequency band if the speech encoder selects a predetermined coding rate for encoding the speech signal.

5. The signal processing apparatus according to

claim 2

, wherein the noise suppressor stops suppressing background noise contained in the speech signal if the speech encoder selects a predetermined coding rate for encoding the speech signal.

8. The signal processing apparatus according to

claim 2

, wherein the noise suppressor comprising a parameter setting means for setting a parameter so as to select an optimal noise suppression characteristic, sand parameters varies the noise suppression characteristics.

9. The signal processing apparatus according to

claim 2

, wherein said parameters are set in accordance with the used coding algorithm at the speech encoder.

10. A signal processing apparatus comprising:

a speech decoder having a plurality of different decoding algorithm, decoding the encoded speech signal by using one of said different decoding algorithm;

a noise suppressor having a plurality of different noise suppression characteristics, suppressing noise component contained in the decoded speech signal; and

wherein said noise suppressor selects one noise suppression characteristics in accordance with the used decoding algorithm at the speech encoder.

15. The signal processing apparatus according to

claim 10

, wherein the noise suppressor comprising a parameter setting means for setting a parameter so as to select an optimal noise suppression characteristic, said parameters varies the noise suppression characteristics.

16. The signal processing apparatus according to

claim 10

, wherein said parameter is set in accordance with the used coding algorithm at the speech encoder.

11. A signal processing apparatus comprising:

a speech decoder having a plurality of different decoding rates, decoding the encoded speech signal by using one of said different coding rates;

a noise suppressor having a plurality of different noise suppression characteristics, suppressing noise component contained in the decoded speech signal; and

wherein said noise suppressor selects one noise suppression characteristic in accordance with the used rate at the speech encoder.

12. The signal processing apparatus according to

claim 11

, wherein the noise suppressor only suppressing the noise component contained in the decoded signal having a predetermined frequency band if the speech decoder selects a predetermined rate for decoding the encoded speech signal.

13. The signal processing apparatus according to

claim 11

, wherein the noise suppressor stops suppressing the noise component contained in the decoded speech signal having a predetermined frequency band if the speech decoder selects a predetermined rate for decoding the encoded speech signal.

14. The signal processing apparatus according to

claim 11

, wherein the noise suppressor stops suppressing background noise contained in the decoded speech signal if the speech decoder selects a predetermined ratio for decoding the encoded speech signal.

17. The signal processing apparatus according to

claim 11

, wherein the noise suppressor comprising a parameter setting means for setting a parameter so as to select an optimal noise suppression characteristic, said parameters varies the noise suppression characteristics.

18. The signal processing apparatus according to

claim 11

, wherein said parameter is set in accordance with the used rate at the speech encoder.

19. A signal processing apparatus for use in a device in which a hands-free function is selectively usable, the apparatus comprising:

a noise suppressor having at least two different noise suppression characteristics, suppressing background noise contained in a speech signal; and

said noise suppressor having a switch which selects a suitable suppression characteristic from the different noise suppression characteristics in accordance with the use of the hands-free function.

20. The signal processing apparatus according to

claim 19

, wherein the noise suppressor comprising a parameter setting means for setting a parameter so as to select an optimal noise suppression characteristic, said parameters varies the noise suppression characteristics.

21. The signal processing apparatus according to

claim 20

, wherein said parameter is set in accordance with the use of the hands-free function.

22. A mobile radio communication terminal having a signal processing apparatus, said signal processing apparatus comprising:

a noise suppressor having a plurality of different noise suppression characteristics, suppressing background noise contained in a speech signal;

a speech encoder having a plurality of different coding algorithm, encoding the suppressed speech signal by using one of said different coding algorithm; and

wherein said noise suppressor selects one noise suppression characteristics in accordance with the used coding algorithm at the speech encoder.

23. A mobile radio communication terminal having a signal processing apparatus, said signal processing apparatus comprising:

a noise suppressor having a plurality of different noise suppression characteristics, suppressing background noise contained in a speech signal;

a speech encoder having a plurality of different coding rates, encoding the suppressed speech signal by using one of said different coding rates; and

wherein said noise suppressor selects one noise suppression characteristics in accordance with the used coding rate at the speech encoder.

24. A signal processing apparatus comprising:

a noise suppressor having a plurality of different noise suppression characteristics, suppressing background noise contained in a speech signal, where the number of said noise suppression characteristics is Q (Q;

a positive integer);

a speech encoder having a plurality of different coding algorithm, encoding the suppressed speech signal by using one of said different coding algorithm, where the number of said coding algorithm is P (P;

a positive integer); and

wherein said noise suppressor selects one noise suppression characteristic in accordance with the used coding algorithm at the speech encoder, the following relationship is established;

P≧

Q>

1.

25. A signal processing apparatus comprising:

a noise suppressor having a plurality of different noise suppression characteristics, suppressing background noise contained in a speech signal, where the number of said noise suppression characteristics is Q (Q;

a positive integer);

a speech encoder having a plurality of different coding rates, encoding the suppressed speech signal by using one of said different coding rates, where the number of said coding rates is R (R;

a positive integer); and

wherein said noise suppressor selects one noise suppression characteristic in accordance with the used coding rate at the speech encoder, the following relationship is established;

R≧

Q>

1.

26. A signal processing apparatus comprising:

a noise suppressor having a plurality of different noise suppression characteristics, suppressing background noise contained in a speech signal, said noise suppression characteristics is varied in accordance with a parameter set by a parameter setting means;

a speech encoder having a plurality of different coding algorithm, encoding the suppressed speech signal by using one of said different coding algorithm, where the number of said coding algorithm is P (P;

a positive integer); and

wherein said parameter setting means set a suitable parameter so as to select an optimal noise suppression characteristic in accordance with the used coding algorithm at the speech encoder, where the number of said parameter is S (S;

a positive integer), the following relationship is established;

R≧

S>

1.

27. A signal processing apparatus comprising:

a noise suppressor having a plurality of different noise suppression characteristics, suppressing background noise contained in a speech signal, said noise suppression characteristics is varied in accordance with a parameter set by a parameter setting means;

a speech encoder having a plurality of different coding rates, encoding the suppressed speech signal by using one of said different coding rates, where the number of said coding rates is R (R;

a positive integer); and

wherein said parameter setting means set a suitable parameter so as to select an optimal noise suppression characteristic in accordance with the used coding rate at the speech encoder, where the number of said parameter is S (S;

a positive integer), the following relationship is established;

R≧

≧

S>

1.