Active Noise Control with

Automatic Adjustment of Control Parameters

1 2 1 2

TMS320 C6713 DSK (Active Noise ControlANC)

(FIR)(LMS) C (real-time)

30dB 40dB 25Hz50Hz24.34dB8.21dB 17dB 15dB

ANC C6713 DSK ANC

Abstract

The purpose of this paper is to conduct active noise control (ANC) experiment in duct and 3-D open sound space using the adaptive filter theory with digital signal processor (DSP) TMS320 C6713 DSK (DSP Starter Kit) , and perform ANC experiment with automatic adjustment of control parameters. We first research the ANC of sound fields for one- dimensional square duct and three-dimensional open space field. We develop the programs of two componential elements of the adaptive filter, filter structure (FIR) and adaptive algorithm (LMS), into program with C language. Then we use real-time DSP as the core of whole hardware structure and transform the continuous analog sound signals into discrete digital ones. Finally, we can get the required signals using the control algorithm. Except the noise reduction, we also take down control parameters. In one-dimensional duct sound field, pure tone signals have average 30dB noise reduction; dual sine signals have the highest 40dB noise reduction. In band noise signals, the individual average noise reduction are 24.34dB and 8.21dB with bandwidth 25Hz and 50Hz . In three-dimensional open space, pure tone signals have average 17dB noise reduction ; dual sine signals have over 15dB noise reduction.

Then we try to adjust two parameters with assembler for step-size and sampling frequency automatically. We can shorten time to attach the maximum control results instead of parameters adjustment in hand and results like this. Confirmed by the result, C6713 DSK can be used as the workbench for the initial programming simulation and experiment design of ANC commercialization.

(source)(path)(receiver)(Active Noise Control , ANC) Paul Lueg(1898-1979)

(secondary sound)(primary sound)180(fighting noise with noise)(acoustic feedback)(secondary path)(system identify)

[1-10]ANC(real time)(Digital Signal ProcessorDSP)80ANCANC

(Finite Impulse ResponseFIR)(Infinite Impulse ResponseIIR)[2]LMS

ANC(2006)TMS320 C6713[10-15]ANC ANC )z(H s y(n):[2,10]

)()()( nxnhnx s FXLMS

)()(x)(w)1(w nennn

FXNLMS

)()()(

)()( nenxnP

nwnwx

1

: 1.ANC2.

ANC3.ANC(FIR)(LMS)(Texas InstrumentsTI)DSKC6713DSK CCS 2.0C(real-time)(DSP)ANC

FXLMSANCANCANC

1

ANC 2 245 ( 13 ) 15 112 120 245 20; 16.5 1.75

2

2

ANCANC85851055

:

200Hz 1000Hz

1 ANC

ANC ANC ANC DSP ANC LMS 200Hz 400Hz 500Hz 1000Hz

N

[52]

: 200Hz400 Hz500Hz 1000Hz 6 : 200Hz500Hz 25Hz50Hz

1 ()

(Hz) (dB) 200Hz 49.49 400Hz 37.23 500Hz 28.96 1000Hz 32.57

2 ()()

3

(Hz) (dB) (Hz) (dB)

200Hz 46.28 25Hz 29.51 200Hz+400Hz

400Hz 34.54 200Hz

50Hz 11.31 200Hz 47.76 25Hz 19.17

200Hz+500Hz 500Hz 29.38 50Hz 5.11 200Hz 42.24

500Hz 1000Hz 30.33

200Hz+1000Hz 1000Hz 26.20 400Hz 26.95

400Hz+500Hz 500Hz 27.02 400Hz 25.96

400Hz+1000Hz 1000Hz 26.63 500Hz 26.32

500Hz+1000Hz 1000Hz 30.33

4

2 ANC

ANCDSPANC

: 200Hz400 Hz500Hz1000Hz200Hz3

3 () 4 ()

(Hz) (dB)

200Hz 12.76 400Hz 14.11 500Hz 15.42 1000Hz 25.86

(Hz) (dB) 400Hz 10.90

400Hz+500Hz 500Hz 17.72 400Hz 13.51

400Hz+1000Hz 1000Hz 21.12 500Hz 19.55

500Hz+1000Hz 1000Hz 21.81

5

6

3 ANC

TMS320 C6713 DSK

0.005 0.0001

: 200Hz400 Hz500Hz 1000Hz 125Hz250Hz625Hz

5 ()

(dB) 200Hz 0.0227 96kHz 35.46 400Hz 0.0084 96kHz 28.36 500Hz 0.0574 96kHz 26.43

1000Hz 0.0482 48kHz 28.95 125Hz 0.0208 16kHz 30.32 250Hz 0.0519 48kHz 25.75 625Hz 0.0807 96kHz 18.22

6 ()

(Hz) sf (dB)

200Hz 38.41 200Hz+400Hz

400Hz 0.0226 96kHz

19.37 200Hz 37.16

200Hz+500Hz 500Hz

0.0277 96kHz 19.59

200Hz 38.35 200Hz+1000Hz

1000Hz 0.0282 32kHz

21.68 400Hz 21.24

400Hz+500Hz 500Hz

0.0309 96kHz 20.98

400Hz 18.13 400Hz+1000Hz

1000Hz 0.0187 96kHz

26.58 500Hz 24.73

500Hz+1000Hz 1000Hz

0.0093 16kHz 20.83

125Hz 28.30 125Hz+250Hz

250Hz 0.0192 16kHz

17.49 125Hz 27.47

125Hz+625Hz 625Hz

0.0172 16kHz 16.22

250Hz 20.37 250Hz+625Hz

625Hz 0.0138 16kHz

16.99

ANC

1. ANC

2. ANC200Hz~1000Hz

20dB625dB200Hz500Hz25Hz50Hz29.51dB11.31dB19.17dB5.11dB

3. ANC200Hz~1000Hz3400Hz15dB

4. ANC

5.

6. ANC

C6713 DSKANC

1. 1000Hz

100Hz

2.

3.

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