Method and device for comparing signals to control transducers and transducer control system

• US 20030108208A1
• Filed: 12/23/2002
• Published: 06/12/2003
• Est. Priority Date: 02/17/2000
• Status: Abandoned Application

• Current Assignee: Orange S.A.
• Original Assignee: Orange S.A.
• Inventors: Thomas, Jean-philippe, Emerit, Marc
• Application Number:
  US10/203,856
• Publication Number:
  US 20030108208A1
• Time in Patent Office: Days
• US Class Current: 381/71.12
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F

Abstract

A method of comparison between pieces of information characterizing reference values and pieces of information characterizing current values of sound-reproducing systems of a system of (n) microphones m_i and (p) speakers hp_j for the control of said sound-reproducing systems characterized in that:

A: for each speaker hp_j,

at least one sound signal S is sent on the speaker hp_j,

for each microphone m_i, a piece of information hp_jm_i is retrieved, this piece of information characterizing the sound-reproducing system comprising the speaker hp_j and the microphone m_i,

B: a reference matrix Q_r is saved, this reference matrix being constituted by all the pieces of reference information hp_jm_i obtained following the sending of the sound signal S,

C: as soon as a comparison is to be made, the step A is run with a sound signal S′ to obtain current information on a matrix Q,

D: the matrices Q and Q_r are compared.

Claims

1. Method of comparison between pieces of information characterizing reference values and pieces of information characterizing current values of sound-reproducing systems of a system of (n) microphones m_i and (p) speakers hp_j for the control of said sound-reproducing systems characterized in that:

A;

for each speaker hp_j,

at least one sound signal S is sent on the speaker hp_j,

for each microphone m_i, a piece of information hp_jm_i is retrieved, this piece of information characterizing the sound-reproducing system comprising the speaker hp_j and the microphone m_i,

B;

a reference matrix Q_r is saved, this reference matrix being constituted by all the pieces of reference information hp_jm_i obtained following the sending of the sound signal S,

C;

as soon as a comparison is to be made, the step A is run with a sound signal S′

to obtain current information on a matrix Q,

D;

the matrices Q and Q_r are compared.

2. Method according to claim 1 characterized in that, when the pieces of information hp_jm_i of Q are not directly comparable with the pieces of information of Q_r, a processing operation, capable of converting them into information directly comparable with the information of the other matrix, is applied to the elements hp_jm_i from a Q or Q_r by choice, before the step D.

3. Method according to one of the claims 1 or 2 characterized in that the pieces of information hp_jm_i of Q_r and/or of Q are the spectral responses of each sub-system including a speaker hp_j and a microphone m_i.

4. Method according to claim 3, characterized in that the signals sent by the speakers hp_j are transmitted in a frequency band with a determined width, and in that said frequency band is made to slide in order to sweep through the desired spectrum of frequencies.

5. Method according to one of the claims 1 or 2, characterized in that the pieces of information hp_jm_i of Q_r and/or of Q are the impulse responses of each sub-system including a speaker hp_j and a microphone m_i.

6. Method according to one of the claims 1 or 2, characterized in that the pieces of information hp_jm_i of Q_r and/or of Q are the transfer functions of each sub-system including a speaker hp_j and a microphone m_i.

7. Method according to one of the claims 1 or 2, characterized in that the pieces of information hp_jm_i of Q_r and/or of Q are the gains between the microphones m_i and the speakers hp_j following the signals sent by the speakers hp_j.

8. Method according to one of the claims 1 to 7 characterized in that, from the matrices Q and Q_r,

the mean values respectively of the speakers hp_j, referenced HP_jQ and HP_jQr, are computed by computing:

1/p*Σ

_i hp_jm_i,

and when the value HP_jQ/HP_jQr is outside a predetermined speaker range FHP, the sound-reproducing system comprising the speaker hp_j is corrected by a divergence corresponding to HP_jQr/HP_jQ.

9. Method according to claim 8, characterized in that, in the sound-reproducing system comprising the speaker hp_j, the gain of speaker hp_j is corrected.

10. Method according to one of the claims 1 to 7, characterized in that, from the matrices Q and Q_r,

the mean values respectively of the microphones m_i, referenced M_iQ and M_iQr, are computed by computing:

1/n*Σ

_i hp_jm_i,

and when the value M_jQ/M_jQr is outside a predetermined microphone range FM, the sound-reproducing system comprising the microphone m_i is corrected by a divergence corresponding to M_iQr/M_iQ.

11. Method according to claim 10, characterized in that, in the sound-reproducing system comprising the microphone m_i, the gain of the microphone m_i is corrected.

12. Method according to one of the claims 1 to 11, characterized in that the pieces of information hp_jm_i of the matrices Q and Q_r to be compared represent delays between the sending of the sound signal by each speaker hp_j and the reception of said sound signal by the microphones m_i.

13. Method according to one of the claims 8 to 11, the pieces of information hp_jm_i of Qr and of Q being the impulse responses of each sub-system including a speaker hp_j and a microphone m_i, characterized in that the pieces of information hp_jm_i represent the signals that were received by the microphone m_i and have traveled the direct path between the speaker hp_j and the microphone m_i.

14. Method according to one of the claims 8 to 11, the pieces of information hp_jm_i of Qr and of Q being the impulse responses of each sub-system including a speaker hp_j and a microphone m_i, characterized in that the pieces of information hp_jm_i represent the signals that were received by the microphone m_i and have traveled the paths with one or more reflections between the speaker hp_j and the microphone m_i.

15. Method according to one of the claims 1 to 14, characterized in that the signal S′

is a silence signal and in that, from the matrices Q and Q_r, the mean values of the microphones m_i, referenced M_iQ and M_iQr, are computed respectively in computing;

1/n*Σ

_j hp_jm_i, to thus obtain the signal-to-noise ratio M_iQr/M_iQ of the microphones m_i.

16. Method according to one of the above claims, characterized in that the pieces of information hp_jm_i are processed remotely through a telecommunications or computer network.

17. Method according to one of the claims 1 to 15 characterized in that the signals S and S′

come from a remote room connected to a local room through a telecommunications network and wherein the pieces of information hp_jm_i are processed in the local room.

18. Method according to one of the claims 1 to 11, characterized in that the pieces of information hp_jm_i of Q_r and Q to be compared represent the echo and in that the signals S and S′

come from a remote room connected to a local room through a telecommunications network.

19. Method for the comparison of information characterizing sound-reproducing systems, at a point of a telecommunications network connecting remote rooms equipped with a system of n microphones m_i and p speakers hp_j, each room being connected to the point of the network by one or more transmission channels k, characterized in that the sound-reproducing systems r_ke_k′

comprise a transmission channel k and a transmission channel k′

resulting from one or more sound-reproducing systems hp_jm_i internal to each room processed according tone of the claims 1 to 18, and in that the elements of the matrices Q and Q_r represent pieces of information characterizing the sound-reproducing systems r_ke_k′

.

20. Method according to one of the above claims, characterized in that the signals S and/or S′

are constituted by a white noise or a pink noise or an USASI noise or a pseudo-random binary sequence.

21. Method according to one of the claims 1 to 20, characterized in that it consists in using the same signal S to obtain the matrices Q_r and Q.

22. Device for comparing pieces of information characterizing reference values and pieces of information characterizing current values of sound-reproducing systems of a system of n microphones m_i and p speakers hp_j for the control of the sound-reproducing system, characterized in that the control system comprises means for the measurement of the pieces of information hp_jm_i characterizing the sound-reproducing systems comprising a microphone m_i and a speaker hp_j, digital processing means to compare said pieces of information hp_jm_i and, connected to these digital processing means, means for saving the matrix Q_r constituted by all the pieces of information hp_jm_i.

23. Device according to claim 22, characterized in that the digital processing means comprise means for the comparison of the matrix Q_r and a matrix Q constituted by pieces of information hp_jm_i characterizing the current values.

24. Device according to claim 22 or 23, characterized in that the digital processing means comprise means to generate sound signals (S) on the speakers hp_j.

25. Device according to claim 24, characterized in that the sound signals (S) may be a white noise or a pink noise or an USASI noise or a pseudo-random binary sequence.

26. Device according to one of the claims 22 to 25, characterized in that the processing means comprise means to correct the sound-reproducing system comprising a speaker hp_j and a microphone m_i.

27. Device according to claim 26, characterized in that, in the sound-reproducing system comprising the speaker hp_j, the gain of the speaker hp_j is corrected.

28. Device according to claim 26, characterized in that, in the sound-reproducing system comprising the microphone m_i, the gain of the microphone m_i is corrected.

29. System for the control of sound-reproducing systems comprising several devices according to one of the claims 22 to 28, characterized in that the devices are distributed among several rooms and in that the control system comprises a high bit-rate telecommunications network connecting said rooms and means to centralize the management of the devices.

30. System according to claim 29, characterized in that the means to centralize the management of the devices are located at a point of the telecommunications network connecting the remote rooms, each room being connected to the point of the network by one or more transmission channels k, in that the sound-reproducing systems r_ke_k′

comprising a transmission channel k and a transmission channel k′

result from one or more sound-reproducing systems hp_jm_i internal to each room and in that it comprises means to correct the sound-reproducing systems r_ke_k′

.