Multi-filter-set active adaptive control system

• US 5,557,682 A
• Filed: 07/12/1994
• Issued: 09/17/1996
• Est. Priority Date: 07/12/1994
• Status: Expired due to Term

• Current Assignee: Digisonix Incorporated
• Original Assignee: Digisonix Incorporated
• Inventors: Kuhn, Scott D., Warner, Jay V., Delfosse, Kent F.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): HARVEY, MINSUN OH
• Application Number:
  US08/273,919
• Time in Patent Office: 798 Days
• Field of Search: 381/72, 381/71, 381/94
• US Class Current: 381/71.11
• CPC Class Codes: G10K 11/17817 between the output signals and the error signals, i.e. secondary path
• CPC Class Codes: G10K 11/17819 between the output signals and the reference signals, e.g. to prevent howling
• CPC Class Codes: G10K 11/17854 the filter being an adaptive filter
• CPC Class Codes: G10K 11/17881 the reference signal being an acoustic signal, e.g. recorded with a microphone
• CPC Class Codes: G10K 2210/3012 Algorithms
• CPC Class Codes: G10K 2210/3019 Cross-terms between multiple in's and out's
• CPC Class Codes: G10K 2210/3027 Feedforward
• CPC Class Codes: G10K 2210/3031 Hardware, e.g. architecture

Abstract

A multi-filter-set active adaptive control system includes a plurality of output transducer arrays introducing control signals to combine with a system input signal to yield a system output signal. A plurality of error transducers sense the system output signal and provide a plurality of error signals to a plurality of sets of adaptive filters. A plurality of sets of D/A converters are provided at the outputs of the adaptive filters outputting correction signals therethrough. A plurality of sets of A/D converters are provided at the filter inputs and error inputs of the adaptive filters. Various filter sets and combinations are provided.

Claims

1. A multi-filter-set active adaptive control system comprising:

a plurality of output transducer arrays introducing control signals to combine with a system input signal to yield a system output signal, each array comprising at least one output transducer;

a plurality of error transducers sensing said system output signal and providing a plurality of error signals;

a plurality of sets of adaptive filters, each set residing on a separate digital signal processor and comprising at least one adaptive filter;

a plurality of sets of D/A converters, one set for each output transducer array, each set comprising at least one D/A converter;

a plurality of sets of A/D converters, each adaptive filter having a plurality of error inputs, each error input receiving a respective error signal through a respective A/D converter from a respective error transducer,

wherein at least one error signal from an error transducer is transmitted to at least two A/D converters, each of the two A/D converters being in a separate set of A/D converters.

2. The invention according to claim 1 further comprising a plurality of sets of C filters, one set for each set of adaptive filters each set of C filters comprising a plurality of C filters, at least one C filter for each error transducers, each C filter of each set having an output combined with the output of a respective A/D converter of a respective set of A/D converters.

3. The invention according to claim 1 further comprising:

a reference input transducer array sensing said system input signal, said array comprising at least one reference input transducer providing at least one reference signal;

a plurality of reference A/D converters, one for each of said adaptive filters, each adaptive filter having an input receiving a reference signal through a respective reference A/D converter,

wherein the reference signal is transmitted to at least two A/D converters, each of the two A/D converters being in a separate set.

4. The invention according to claim 1 wherein said adaptive filter sets comprise:

a plurality of sets of A filters, each set having an A filter for each reference input transducer, and a plurality of sets of B filters, each set having a B filter for each output transducer array, each A filter having an output summed at a summer with the outputs of the remaining A filters of its respective set and with the outputs of the B filters of its respective set, the output of said summer providing said correction signal; and

a plurality of sets of feedback A/D converters, one set for each output transducer array, each set comprising at least one feedback A/D converter.

5. The invention according to claim 4 wherein the number of feedback A/D converters in each set is one less than the number of output transducer arrays, and each set of B filters has a first B filter with an input from the summer of its respective A filter set prior to passing through its respective D/A converter, and wherein each of the remaining B filters of each set has an input from a respective A/D converter receiving a correction signal from the summer of another A filter set after passing through its respective D/A converter, such that each input to each of said remaining B filters first passes through said D/A converter of said other A filter set and then passes through said feedback A/D converter of the respective said remaining B filter.

6. The invention according to claim 1 wherein said adaptive filter sets comprise:

a plurality of sets of A filters, each set having an A filter for each reference input transducer, and a plurality of sets of B filters, each set having a B filter for each output transducer array, and comprising a first set of summers, one for each output transducer array, each summer summing the outputs of the A filters of a respective set, said plurality of sets of D/A converters comprising a first set of D/A converters, one for each summer of said first set of summers, a second set of summers, one for each summer of said first set of summers, a second set of D/A converters, one for each summer of said second set of summers, a third set of summers, one for each D/A converter of said second set of D/A converters, a plurality of sets of feedback A/D converters, one set for each output transducer array.

7. The invention according to claim 6 wherein each set of feedback A/D converters comprises a plurality of feedback A/D converters, one for each B filter of its respective set, the number of feedback A/D converters in each set being equal to the number of output transducer arrays, each summer of said second set of summers summing the outputs of the respective D/A converters of said first set of D/A converters and the outputs of the respective D/A converters of said second set of D/A converters and supplying the resultant sum to the respective output transducer array, each summer of said third set of summers summing the outputs of the respective set of B filters and supplying the resultant sum through the respective D/A converter of said second set of D/A converters to the respective summer of said second set of summers, each B filter having an input through the respective feedback A/D converter of the respective set of feedback A/D converters from the respective summer of said second set of summers.

8. A multi-filter-set active adaptive control system comprising:

a plurality of output transducer arrays introducing control signals to combine with a system input signal to yield a system output signal, each array comprising at least one input transducer;

a plurality of error transducers sensing said system output signal and providing a plurality of error signals;

a plurality of adaptive A filters, one for each of said output transducer arrays, each A filter residing on a separate digital signal processor;

a plurality of D/A converters, one for each output transducer array, each A filter outputting a correction signal through its respective D/A converter to its respective output transducer array to introduce said control signal;

a plurality of sets of A/D converters, one set for each of said A filters, each set comprising a plurality of A/D converters, one for each of said error transducers, each A filter having a plurality of error inputs, one for each A/D converter of its respective set, each error input receiving a respective error signal through its respective A/D converter from its respective error transducer.

9. The invention according to claim 8 comprising a plurality of sets of C filters, one set for each A filter, each set comprising a plurality of C filters, one for each of said error transducers, each set of C filters having an input from the input to the respective A filter, each C filter of each set having an output combined with the output of a respective A/D converter of the respective set of A/D converters, each C filter modeling the transfer function from its respective output transducer to its respective error transducer.

10. The invention according to claim 8 comprising:

a reference input transducer sensing said system input signal and providing a reference signal;

a plurality of reference A/D converters, one for each of said A filters, each A filter having an input receiving said reference signal through its respective reference A/D converter from said reference input transducer.

11. The invention according to claim 8 comprising a plurality of sets of adaptive B filters, one set for each A filter, each set comprising a plurality of B filters, one for each output transducer array, each A filter having an output summed at a summer with the outputs of the B filters of its respective set, the output of said summer providing said correction signal, a plurality of sets of feedback A/D converters, one set for each A filter, the number of feedback A/D converters in each set being one less than the number of output transducer arrays, each set of B filters having a first B filter with an input from the summer of its respective A filter prior to passing through its respective D/A converter, the remaining B filters of each set having an input from a respective feedback A/D converter receiving a correction signal from the summer of another of said A filters after passing through its respective D/A converter, such that each input to each of said remaining B filters first passes through said D/A converter of said other A filter and then passes through said feedback A/D converter of the respective said remaining B filter.

12. The invention according to claim 8 comprising a plurality of sets of adaptive B filters, one set for each A filter, each set comprising a plurality of B filters, one for each output transducer, and comprising a first set of summers, one for each output transducer, said plurality of D/A converters comprising a first set of D/A converters, one for each summer of said first set of summers, and further comprising a second set of summers, one for each summer of said first set of summers, a second set of D/A converters, one for each summer of said first set of summers, a plurality of sets of feedback A/D converters, one set for each A filter, each set comprising a plurality of A/D converters, one for each B filter of its respective set, the number of feedback A/D converters in each set being equal to the number of output transducers, each summer of said first set summing the output of the respective D/A converter of said first set and the output of the respective D/A converter of said second set and supplying the resultant sum to the respective output transducer, each summer of said second set summing the outputs of the respective set of B filters and supplying the resultant sum through the respective D/A converter of said second set of D/A converters to the respective summer of said first set of summers, each B filter having an input through the respective feedback A/D converter of the respective set of feedback A/D converters from the respective summer of said first set of summers.

13. A multi-filter-set active adaptive control system comprising:

first and second output transducer arrays introducing control signals to combine with a system input signal to yield a system output signal, each array comprising at least one output transducer;

a reference input transducer sensing said system input signal and providing a reference signal;

first and second adaptive A filters;

first, second, third and fourth adaptive B filters;

the first adaptive A filter and the first and second adaptive B filters residing on a first digital signal processor;

the second adaptive A filter and the third and fourth adaptive B filters residing on a second digital signal processor;

first and second summers, said first summer summing the output of said first A filter and the outputs of said first and second B filters, said second summer summing the output of said second A filter and the outputs of said third and fourth B filters;

first and second D/A converters, said first D/A converter supplying the output of said first summer to said first output transducer, said second D/A converter supplying the output of said second summer to said second output transducer;

first, second, third and fourth A/D converters, said first A/D converter supplying said reference signal to the input of said first A filter, said second A/D converter supplying said reference signal to the input of said second A filter, said third A/D converter supplying the output of said second D/A converter to the input of said second B filter, said fourth A/D converter supplying the output of said first D/A converter to the input of said fourth B filter, the input to said first B filter being supplied from the output of said first summer, the input to said third B filter being supplied from the output of said second summer.

14. The invention according to claim 13 comprising:

a second reference input transducer sensing said system input signal and providing a second reference signal;

third and fourth adaptive A filters;

fifth and sixth A/D converters,

said fifth A/D converter supplying said second reference signal to the input of said third A filter,

said sixth A/D converter supplying said second reference signal to the input of said fourth A filter, the outputs of said first and third A filters being summed and supplied with the summation of the outputs of said first and second B filters through said first D/A converter to said first output transducer array, the outputs of said second and fourth A filters being summed and supplied with the summation of the outputs of said third and fourth B filters through said second D/A converter to said second output transducer array.

15. A multi-filter-set active adaptive control system comprising:

first and second output transducer arrays introducing control signals to combine with a system input signal to yield a system output signal, each array comprising at least one output transducer;

a reference input transducer sensing said system input signal and providing a reference signal;

first and second adaptive A filters, the first adaptive A filter residing on a first digital signal processor, and the second adaptive A filter residing on a second digital signal processor;

first, second, third and fourth adaptive B filters, the first and second adaptive B filters residing on a third digital signal processor, and the third and fourth adaptive B filters residing on a fourth digital signal processor;

first, second, third and fourth summers;

first, second, third and fourth D/A converters;

first, second, third, fourth, fifth and sixth A/D converters;

said first summer summing the outputs of said first and third D/A converters and supplying the resultant sum to said first output transducer array;

said second summer summing the outputs of said second and fourth D/A converters and supplying the resultant sum to said second output transducer array;

said third summer summing the outputs of said first and second B filters and supplying the resultant sum through said third D/A converter to said first summer;

said fourth summer summing the outputs of said third and fourth B filters and supplying the resultant sum through said fourth D/A converter to said second summer;

said first A/D converter supplying said reference signal to the input of said first A filter;

the output of said first A filter being supplied through said first D/A converter to said first summer;

said second A/D converter supplying said reference signal to the input of said second A filter;

the output of said second A filter being supplied through said second D/A converter to said second summer;

said third A/D converter supplying the output of said second summer to the input of said first B filter;

said fourth A/D converter supplying the output of said first summer to the input of said second B filter;

said fifth A/D converter supplying the output of said first summer to the input of said third B filter;

said sixth A/D converter supplying the output of said second summer to the input of said fourth B filter.

16. The invention according to claim 15 comprising;

a second reference input transducer sensing said system input signal and providing a second reference signal;

third and fourth adaptive A filters;

seventh and eighth A/D converters, said seventh A/D converter supplying said second reference signal to said third A filter, said eighth A/D converter supplying said second reference signal to said fourth A filter;

fifth and sixth summers, said fifth summer summing the outputs of said first and third A filters and supplying the resultant sum through said first D/A converter to said first summer, said sixth summer summing the outputs of said second and fourth A filters and supplying the resultant sum through said second D/A converter to said second summer.

17. A multi-filter-set active adaptive control system comprising:

an output transducer introducing control signals to combine with a system input to yield a system output signal;

an error transducer sensing the output signal and providing an error signal;

an adaptive digital A filter residing on a first digital signal processor and transmitting a digital output;

a first D/A converter that receives a signal comprised at least in part by the A filter digital output and outputs a first analog signal;

an analog summer that receives the first analog signal and a second analog signal and outputs a correction signal that is transmitted to the output transducer and to an A/D converter;

an adaptive digital B filter that receives digital input from the A/D converter and transmits a digital output, the adaptive B filter residing on a second digital signal processor; and

a second D/A converter that receives a signal comprised at least in part by the B filter digital output and outputs the second analog signal.

18. In an active acoustic attenuation system having a system output, the system comprising:

one or more output transducers each outputting a secondary input that combines with the system input to yield the system output;

a plurality of error transducers sensing the system output, each error transducer outputting an analog error signal; and

multiple digital filter sets that collectively generate one or more correction signals to drive the one or more output transducers, each digital filter set having at least one adaptive digital filter and at least one A/D converter, the one or more adaptive digital filters of each digital filter set residing on a separate digital signal processor from the one or more adaptive digital filters of the other one or more digital filter sets;

wherein each digital filter set includes at least one A/D converter that receives the same analog error signal as one of the A/D converters in another digital filter set.

19. In an active acoustic attenuation system having a system input and a system output, the system comprising:

one or more output transducers each outputting a secondary input that combines with the system input to yield the system output;

a plurality of input transducers sensing the system input, each input transducer outputting an analog reference signal; and

multiple digital filters sets that collectively generate one or more correction signals to drive the one or more output transducers, each digital filter set having at least one adaptive digital filter and a set of A/D converters, the one or more adaptive digital filters of each digital filter set residing on a separate digital signal processor from the one or more adaptive digital filters of the other one or more digital filter sets;

wherein the digital filter set includes at least one A/D converter that receives the same analog reference signal as one of the A/D converters in another digital filter set.

20. In an active acoustic attenuation system having one or more output transducers each outputting a secondary input that combines with a system input to yield a system output, the improvement comprising:

multiple digital filter sets that collectively generate one or more correction signals to drive the one or more output transducers, each digital filter set having;

at least one adaptive digital filter having a digital output, the one or more adaptive digital filters of each digital filter set residing on a separate digital signal processor from the one or more adaptive digital filters of the other one or more digital filter sets;

a D/A converter that receives a digital signal comprised at least in part from the digital output from said adaptive digital filter, the D/A converter transmitting an analog signal from the digital filter set; and

an A/D converter that receives an analog signal from at least one of the other multiple digital filter sets.

21. The invention according to claim 20 wherein the analog signal from the digital filter set is one of the correction signals which drives the one or more output transducers.