Acoustic Duct
Acoustical Material Measurement System
 | |
| |
|
Overview of Acoustic Ducts
Acoustic Duct is designed to measure the characteristics of acoustical material such as sound absorber and sound barrier. The two-microphone random-excitation technique is adopted to separate the incident and the reflected-wave spectra in a duct.
Not only generating the White or the pink noise but also measuring the signals and calculation of acquired data are provided by the personal computer without any other FFT Analyser. The developed software is suitable for the Windows 98 and the NT operating systems.
Main Function of Acoustic Ducts
|
Real Time FFT |
|
Signal Generation |
|
Real Time Octave Analysis |
|
Auto-, Cross-Spectrum Measurement |
|
Calculation of Absorption Ratio |
|
Calculation of Transmission Loss |
|
Microphone Calibration |
|
Database |
Specifications of Acoustic Duct
|
Computer |
|||
|
Processor |
733MHz or higher |
||
|
Co-processor |
Compulsory |
||
|
RAM |
128MB or higher |
||
|
VGA card |
32M or higher |
||
|
Operating system |
Windows 98 or NT |
||
|
Printer |
HP deskjet |
||
|
Unit for display |
19" color monitor |
||
|
Hard disk |
20GB |
||
|
Hardware System for Measurement |
|||
|
Duct for measurement |
|
||
|
Frequency range |
Name of duct |
Dia (mm) |
Length (mm) |
|
Measuring
at low frequency range |
Signal generating 1EA |
102.5 |
640 |
|
Fixing insulation material 2EA |
108 |
20, 30, 50, 100 |
|
|
Calibrating 1EA |
102.5 |
400 |
|
|
Fixing absorption material 2EA |
102.5 |
50, 100 |
|
|
Measuring at high frequency range [500Hz ~ 6300Hz] |
Signal generating 1EA |
30 |
320 |
|
Fixing insulation material 2EA |
35 |
20, 30, 50, 100 |
|
|
Calibrating 1EA |
30 |
15 |
|
|
Fixing absorption material 2EA |
30 |
50, 100 |
|
|
Power supply & Amplifier |
|
||
|
Power supply |
Signal
output CH 1EA |
||
|
Signal input CH 4EA |
|||
|
DC coupling 12V & 0.1A |
|||
|
Amplifier |
Amplification
of current |
||
|
Microphone |
|
||
|
Diameter |
1/4 [inch] |
||
|
Frequency range |
20Hz
- 15kHz : ±3dB |
||
|
Sensitivity |
50mV/Pa ± 5% |
||
|
Max SPL |
124dB |
||
|
Temperature range |
-10 ~ 50 °C |
||
|
Output socket |
BNC jack |
||
|
Noise |
lin (20Hz ~ 20kHz) |
||
|
Data acquisition unit |
|
||
|
Sampling rate |
300k / total & 75k / Channel |
||
|
Resolution |
16bit |
||
|
Gain control |
Control by Programming (1/10/100/1000) |
||
|
Signal input type |
Signal ended (Must be installed on earth) |
||
|
A/D & D/A |
16 Channel & 2 Channel |
||
|
Calibration |
Self - Calibration |
||
|
Unit for calibration |
|
||
|
Testing sample for calibration |
Low frequency & High frequency |
||
|
Dummy microphones |
4EA |
||
|
Others units |
|
||
|
BNC cable |
(2.5m 2set & 1.5m 1set) |
||
|
Signal generator |
sine wave, swept sine wave, white-noise, pink-noise...etc |
||
|
Speaker 2ea |
For low frequency & high frequency |
||
|
Environmental System |
measuring system of temperature & humidity |
||
|
System for cutting of material |
Main system & cutting blade |
||
|
System for measuring density and size of material |
|||
|
|
|
||
|
Software for Measurement |
|||
|
Real time data analysis |
|
||
|
FFT module |
Time data => Freq data |
||
|
FRF module |
Data for calibration |
||
|
Auto-spectrum |
Averaged freq data |
||
|
Cross-spectrum |
Data included with amplitude & phase |
||
|
Frequency response function |
Data for calibration |
||
|
Input data display module |
|
||
|
Auto-spectrum |
2 channel & 4 channel |
||
|
Cross-spectrum |
Real & imaginary |
||
|
Result data display module |
|
||
|
Absorption ratio |
0.0 ~ 1.0 (default range) controlled by user |
||
|
Transmission loss |
0dB ~ 60dB (default range) controlled by user |
||
|
Normalized impedance |
Real & imaginary |
||
|
Frequency response function |
Amplitude & phase |
||
|
Indexed of performance of material |
Absorption coefficient |
||
|
Calibration module |
Axis display module |
||
|
Absorption coefficient |
1/1, 1/3.....1/n Octave band |
||
|
Transmission loss |
Narrow band |
||
|
Normalized impedance |
Linear scale |
||
|
Reflection coefficient |
Log scale |
||
