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THE INSTITUTE OF ELECTRONICS, IEICE Technical Report INFORMATION AND COMMUNICATION ENGINEERS
This article is a technical report without peer review, and its polished and/or extended version may be published elsewhere.
Copyright ©2015 by IEICE
120-8551 5 E-mail: { 13kmc05@ms kaneda@c}.dendai.ac.jp
SN
DA LPF
A Study of nonlinear error in the impulse response measurement
using swept sine signal
Noritaka SATO and Yutaka KANEDA
Graduate School of Engineering, Tokyo Denki University, 5 Senju-asahi-cho, Adachi-ku, Tokyo 120-8551, Japan E-mail: { 14kmc13@ms kaneda@c }.dendai.ac.jp
Abstract The impulse response is an important characteristic for determining the frequency characteristic or reverberation time of acoustic systems. When an impulse response is measured using an excitation signal with a high sound pressure level to improve the SN ratio, nonlinear distortion occurs. The nonlinear distortion appears as a well-known harmonic distortion when a swept sine signal is used as an excitation signal. However, unexplained error components sometimes appear. In this report, we examined these error components. We found that the error components are intermodulation distortions caused by the swept sine signal and the reversely aliased signal of the LPF of a DA converter, or are the intermodulation distortions caused by the swept sine signal and the weak noise of the power supply. On the basis of these results, we proposed methods to reduce these errors and confirmed their effectiveness. Key words impulse response measurement, measurement error, nonlinear distortion, harmonic distortion, intermodulation distortion 1.
SN
(SS: Swept Sine)
TSP [1]Log-SS( TSP
ESS: Exponentialy Sept Sine) [2]
SN
(1m 100dB
)
2.
Fig.1( )
S
Copyright ©201 by IEICE 5This article is a technical report without peer review, and its polished and/or extended version may be published elsewhere.
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H1/S
S S HS H
1/S H Fig.2 TSP Fig.3 Log-SS
TSP (Fig.2(a))TSP (Fig.2(b):
)(Fig.2(c)) Fig.3
(a)(b)(c) 3.
Fig.4
( ) Log-SS
Fig.5, 6
Fig.5 TSP(a) (b)
Fig.6(a)(b)Log-SS
Fig.5(a) TSP
Fig.5(b)
() Fig.5(a) n (n=2,3,4 )
n ( 2 3)
Fig.5(b)Fig.6(a)(b)
Log-SSFig.6(b)
fs/2(fs )
AD
H 1/SS S H HFig.1
Fig.2 TSP
(a) (b) (c)
Fig.3 Log-SS
(a) (b) (c)
DA AD
PCFig.4
(a)
(b)
Fig.5 TSP (a) (b)
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[3] DA(
) Fig.6(b)
TSP Log-SS
Fig.5, 6
4. 4.1.
AD DA(LPF) fs/2(fs: )
AD DALPF fs/2fs/2 [4] Fig.7 LPF ADDA fs/2 f1
fs/2 fs f1 DAfs/2
Fig.8 fs=48kHz DA TSP 96kHz
TSPfs/2 fs/2
DATSP DA f1
fs f1 2f1 fs
fs f1
[3][4] 4.2.
Fig.7,8 0.9*fs/2 fs/2 fs/2 1.1*fs/2
DA 0.9*fs/2
LPFADAD
LPF
Fig.9 TSPFig.9(a)(b) Fig.10DA LPF ADLPF LPF
Fig.6 Log-SS(a) (b)
(a)
(b)
Fig.7 DA AD LPF ( 1 fs/2 )
Fig.8 TSP
fs/2
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Fig.10
Fig.8 26kHzDA LPF 26kHz
5. 5.1.
Fig.11 Log-SS
Fig.12(a)
Fig.13Log-SS
TSP
Fig.14(a)(b)TSP
Fig.13 Log-SSFig.15
( ( 20 )TSP )
(a)
(b)
Fig.10 TSP
Fig.12 Log-SS
Fig.13 Log-SS
Fig.11 Log-SS
(b)
(a)
Fig.9 TSP
Fig.14 TSP
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Fig.15 0.05TSP
2.2kHz/s Fig.14(a)100Hz
100Hz
TSP
( )
TSP 2
(Fig.16(a))
Fig.16(b) TSP-70 dB
50 Hz
TSP
100 Hz 5.2.
Fig.17Fig.18 Fig.17
Fig.18 Fig.17
Fig.19 Fig.17 Fig.17Fig.19 Log-SS
DFT
Fig.20 120HzFig.20 120Hz
Fig.16
Fig.18 Fig.17
Fig.17
Fig.19 Fig.17
Fig.15 TSP
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( :240Hz,360Hz,..)
50Hz100Hz
2 240Hz220Hz( 120Hz 100Hz) 260Hz( 3
360Hz 100Hz) 50Hz 100Hz
120Hz50Hz 100Hz
5.3.
PC PC USB(AD/DA)
BOSE101MM(45W)
Fig.21 Log-SS
Fig.21 Fig.11Fig.17
Fig.21
6.
DA/AD LPF
JSPS 15H02728
[1] Y. Suzuki, F. Asano, H. Y. Kim, and T. Sone,”An Optimum
computer-generated pulse signal suitable for the measurement of very long impulse responses,” J. Acoust. Soc. Am. 97, 2,1119-1123, 1995.
[2] , ” SNTSP ”,
, 3-P-18, 2000. [3] , , , “TSP
PC AD/DA ”, , 3-Q-13, 2006.
[4] , , , “AD/DA”,
, 1-P4-2, 2014.
Fig.20 120Hz
Fig.21 Log-SS
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