التفاصيل البيبلوغرافية
| العنوان: |
DIRECTIONAL SOUND SYSTEM |
| Document Number: |
20120148053 |
| تاريخ النشر: |
June 14, 2012 |
| Appl. No: |
13/391000 |
| Application Filed: |
August 25, 2010 |
| مستخلص: |
A directional sound system is disclosed. The directional sound system (400) comprises a plurality of equalization stages (404, 406) configured to equalize an input signal; and a transducer stage (412) configured to transmit the equalized input signal; wherein the plurality of equalization stages (404, 406) comprises a first equalization stage (404) configured to employ an approximated model of the transducer stage (412) and a second equalization stage (406) configured to compensate for differences between the approximated model of the transducer stage (412) and an actual model of the transducer stage (412). |
| Inventors: |
Tan, Ee Leng (Singapore, SG); Gan, Woon Seng (Singapore, SG) |
| Claim: |
1. A directional sound system comprising: a plurality of equalization stages configured to equalize an input signal; and a transducer stage configured to transmit the equalized input signal; wherein the plurality of equalization stages comprises a first equalization stage configured to employ an approximated model of the transducer stage and a second equalization stage configured to compensate for differences between the approximated model of the transducer stage and an actual model of the transducer stage. |
| Claim: |
2. A directional sound system according to claim 1, further comprising a modulation stage configured to modulate the equalized input signal from the first equalization stage prior to the second equalization stage, wherein the modulation stage employs a modulation technique which uses a pre-distortion term with a variable order. |
| Claim: |
3. A directional sound system according to claim 2, wherein the modulation technique comprises: modulating an input to the modulation technique with a first carrier signal to produce a main signal; multiplying the pre-distortion term with a second carrier signal orthogonal to the first carrier signal to produce a compensation signal; and summing the main signal and the compensation signal to generate an output of the modulation technique. |
| Claim: |
4. A directional sound system according to claim 2, wherein the first equalization stage is further configured to compensate for one or more expected changes in the input signal after demodulation and to compensate for the frequency and phase response of the transducer stage, wherein the first equalization stage is configured to compensate for an expected 12 dB/octave slope change in the input signal after demodulation. |
| Claim: |
5. (canceled) |
| Claim: |
6. A directional sound system according to claim 2, wherein the second equalization stage comprises at least one adaptive filter, wherein in use the at least one adaptive filter is trained with a least mean square algorithm using a difference between a first signal and a second signal; wherein the first signal is obtainable by double integrating the input signal and processing the double integrated signal through an inverse of the actual model of the transducer stage and the second signal is obtainable using the equalized input signal from the first equalization stage. |
| Claim: |
7. (canceled) |
| Claim: |
8. A directional sound system according to claim 2, wherein the directional sound system further comprises an amplification stage for amplifying the equalized input signal prior to the transducer stage. |
| Claim: |
9. A directional sound system according to claim 2, wherein the transducer stage comprises an ultrasonic transducer, and the order of the pre-distortion term for the modulation technique is selected based on a bandwidth of the input signal and a bandwidth of the ultrasonic transducer, wherein a frequency response of the ultrasonic transducer is non-symmetrical and the second equalization stage is further configured to compensate for the non-symmetrical frequency response of the ultrasonic transducer. |
| Claim: |
10. (canceled) |
| Claim: |
11. A directional sound system according to claim 2, wherein the input signal is able to be split into a plurality of frequency regions and each frequency region of the input signal is able to be processed independently through the modulation stage, wherein the input signal is able to be split into a plurality of frequency regions using a plurality of filters in a filter bank and the modulation stage comprises a plurality of modulators with each modulator operably connected to each filter in the filter bank; and wherein at least one modulator is configured to employ the modulation technique with the order of the pre-distortion term for each of the at least one modulator selected based on a bandwidth of the filter operably connected to the modulator, wherein each frequency region of the input signal is able to be processed independently through the first and second equalization stages, wherein the transducer stage comprises a plurality of ultrasonic transducers, each ultrasonic transducer operably connected to a filter of the filter bank and a modulator of the modulation stage; and wherein at least one modulator is configured to employ the modulation technique with the order of the pre-distortion term for each of the at least one modulator selected based on a bandwidth of the filter operably connected to the modulator and a bandwidth of the ultrasonic transducer operably connected to the modulator. |
| Claim: |
12.-14. (canceled) |
| Claim: |
15. A directional sound system according to claim 2, wherein the modulation stage comprises a first modulation stage and the directional sound system further comprises: a second modulation stage configured to further modulate the equalized input signal prior to the transducer stage wherein a carrier frequency of the further modulated equalized input signal is dependent on a first carrier frequency in the first modulation stage and a second carrier frequency in the second modulation stage. |
| Claim: |
16. A directional sound system according to claim 15, wherein the input signal is able to be split into a plurality of frequency regions and each frequency region of the input signal is able to be processed independently through the first and second modulation stages. |
| Claim: |
17. A method for processing an input signal to a directional sound system, the method comprising: repeatedly equalizing the input signal; and transmitting the equalized input signal; wherein a first equalization of the input signal is performed using an approximated model of the transmission and a second equalization of the input signal comprises compensating for the differences between the approximated model of the transmission and an actual model of the transmission. |
| Claim: |
18. A method according to claim 17, wherein the method further comprises modulating the equalized input signal from the first equalization prior to the second equalization by employing a modulation technique which uses a pre-distortion term with a variable order. |
| Claim: |
19. A method according to claim 18, wherein the modulation technique comprises: modulating an input to the modulation technique with a first carrier signal to produce a main signal; multiplying the pre-distortion term with a second carrier signal orthogonal to the first carrier signal to produce a compensation signal; and summing the main signal and the compensation signal to generate an output of the modulation technique. |
| Claim: |
20. A method according to claim 18, wherein the transmission is characterized by a frequency and phase response and wherein repeatedly equalizing the input signal further comprises: compensating for one or more expected changes in the input signal after demodulation; and compensating for the frequency and phase response of the transmission, wherein compensating for one or more expected changes in the input signal after demodulation further comprises compensating for an expected 12 dB/octave slope change in the input signal after demodulation. |
| Claim: |
21. (canceled) |
| Claim: |
22. A method according to claim 18, wherein compensating for the differences between the approximated model of the transmission and the actual model of the transmission is performed adaptively, wherein the adaptive compensation for the differences between the approximated model of the transmission and the actual model of the transmission is performed with a least mean square algorithm using a difference between a first signal and a second signal; wherein the first signal is obtained by double integrating the input signal and processing the double integrated signal through an inverse of the actual model of the transmission and the second signal is obtained using the equalized input signal from the first equalization. |
| Claim: |
23. (canceled) |
| Claim: |
24. A method according to claim 18, further comprising amplifying the equalized input signal prior to the transmission. |
| Claim: |
25. A method according to claim 18, wherein the equalized input signal is transmitted using an ultrasonic transducer and the order of the pre-distortion term for the modulation technique is selected based on a bandwidth of the input signal and a bandwidth of the ultrasonic transducer, wherein a frequency response of the ultrasonic transducer is non-symmetrical and the method further comprises compensating for the non-symmetrical frequency response of the ultrasonic transducer. |
| Claim: |
26. (canceled) |
| Claim: |
27. A method according to claim 18, further comprising splitting the input signal into a plurality of frequency regions prior to repeatedly equalizing the input signal, wherein modulating the equalized input signal further comprises modulating the equalized input signal for each frequency region of the input signal independently, wherein modulating the equalized input signal further comprises modulating the equalized input signal for each frequency region of the input signal independently; wherein the input signal is split into a plurality of frequency regions using a plurality of filters in a filter bank and for at least one frequency region, the modulation technique is employed with the order of the pre-distortion term selected based on a bandwidth of the respective filter of the filter bank. |
| Claim: |
28.-29. (canceled) |
| Claim: |
30. A method according to claim 27, wherein the modulated equalized signal for each frequency region is transmitted using an ultrasonic transducer; and for at least one frequency region, the modulation technique is employed with the order of the pre-distortion term selected based on a bandwidth of the respective filter of the filter bank and a bandwidth of the respective ultrasonic transducer. |
| Claim: |
31. A method according to claim 18, further comprising further modulating the modulated equalized input signal prior to transmitting the equalized input signal wherein a carrier frequency of the further modulated equalized input signal is dependent on a first carrier frequency of the initial modulation and a second carrier frequency of the further modulation; wherein each frequency region of the input signal is processed independently in at least one equalization of the input signal. |
| Claim: |
32. (canceled) |
| Current U.S. Class: |
381/1 |
| Current International Class: |
04 |
| رقم الانضمام: |
edspap.20120148053 |
| قاعدة البيانات: |
USPTO Patent Applications |