Report on Research Activities of KRISS CCAUV

Transcription

1 Report on Research Activities of KRISS CCAUV Division of Physical Metrology Center for Fluid Flow & Korea Research Institute of Standards and Science

2 KRISS - CCAUV Dr. H. S. Kwon hyusang@kriss.re.kr (Air, Water) Dr. S. J. Suh sjs@kriss.re.kr (Air) Dr. W. H. Cho chowanho@kriss.re.kr (Air) Dr. S. S. Jung jss@kriss.re.kr (Air, Hearing) Mr. J. G. Suh sjg@kriss.re.kr (Air, Water) Dr. K. Baik kbaik@kriss.re.kr (Water) Dr. W. S Cheung wansup@kriss.re.kr Vibration (Angular) Dr. Y. B. Lee lyb@kriss.re.kr Vibration (Linear, Seismic) Mr. B. S. Jeon jbs@kriss.re.kr Vibration (Linear, Angular) Improvement of Free-field Sen. Calibration Development of Post Processing Method Low-pass filtering for stabilizing impulse response Extended low frequency limit of calibration below 2 khz. Audiometer calibration system Air conduction audiometer Frequency range : 125 Hz 8000 Hz Hearing level, Linearity, Harmonic distortion, etc. Hydrophone calibration system Free-field reciprocity calibration (under establishment). DAQ: Digitizer PXI Ultrasonic power measurement system & Others Ultrasound Lab. moved to: Centre for Medical Metrology. Fabrication/Calibration of transfer standard transducer(nimt) Voltage response measurement of thermal voltage converter. Evaluation of newly developed ultrasonic absorbing material. Measurement/calibration system for Linear vibration Measurement/calibration system for Angular vibration Interferometer for low frequency phase measurement. Developing transfer standards for comparison calibration. DAQ: Digitizer 100 MS/s, 14 bits. Angle-prism based laser interferometer. Low frequency shaker system for calibration. 2 Hybrid calibration system for linear & angular vibration.

3 Calibration result of LS2 mic. Sensitivity (db) Sensitivity (db) Sensitivity (db) Chebyshev Tukey Rectangular Sensitivity (db) Highlights on Free-field Reciprocity Calibration Development of Post Processing Method (Published on JASA 2013) Applying low-pass filtering for stabilizing impulse response Low frequency limit of calibration can be extended below 2 khz without fitting LPF Steady state response Filtered FRF ifft Impulse response (Filtered) Simulation result with equivalent circuit model Theoratical value Rectangular Tukey Chebyshev Direct path IR (Filtered) Time gating FFT Direct path FRF (Filtered) Inverse LPF Direct path response Minimizing ripple Rectangular -30 Tukey -31 Chebshev Pressure sensitivity -32 with free-field correction A -28 Rectangular -29 Tukey -30 Chebshev -31 Pressure sensitivity -32 with free-field correction Rectangular Tukey -30 Chebshev Pressure sensitivity -33 with free-field -34 correction M1 M2 M3 3

4 Highlights on Free-field Reciprocity Calibration System Renewal Introducing the automation system DFM-B&K free-field reciprocity calibration system Signal processing procedure will be compared with KRISS method Position controller PC B&K NEXUS (Modified) Switch Box Preamp. (B&K 2673) CH. 2 AUX PC LAN IEEE B&K PULSE 3560-C CH. 1 Generator B&K 5998 d=100 mm Microphone (B&K 4180) Transmitter (B&K ZE0796) Pressure Probe (Testo ) RH Probe (Testo ) TESTO 400 Monitoring device 4

5 Sensitivity (db) Correction value (db) Highlights on Free-field Reciprocity Calibration Bilateral Comparison with NIM No Calibration laboratory Artifact Start date Finish date KRISS B&K 4180 S/N Larson Davis 824 S/N 824A August August 2012 NIM B&K 4180 S/N KRISS B&K 4180 S/N NIM B&K 4180 S/N Larson Davis 824 S/N 824A0974 KRISS B&K 4180 S/N Larson Davis 824 S/N 824A0974 NIM B&K 4180 S/N September October November October October November 2012 Mid. December LS2 Microphone (B&K 4180) Sound level meter (Larson Davis 824) KRISS NIM KRISS NIM

6 CN of env. matrix Investigation of Environmental Condition (WS2p) Estimation of correction factor using data collect at the uncontrolled condition (Internoise 2013) Collection method Using the comparison method Data collection period 1~2 years about 1~2 month step Estimation of correction factor Without reference condition data M P T RH p, mea 1 Using mean value as reference condition data M M P T RH M CP CT C p, ref RH C C C p, mea p, ref T P RH Without ref. mic. data With ref. mic. data A B C D E-1 E-2 F G-1 G-2 Microphone 6

7 Investigation of Environmental Condition (WS2p) Estimation of correction factor using data collect at the uncontrolled condition (Internoise 2013) Estimated correction factor More reasonable factor obtained with reference condition 7

8 Highlights on Angular vibration Recent activities: Completed the 1 st comparison in angular vibration (with PTB): CCAUV.V-S1 Reviewed a draft version of Draft A of CCAUV.V-S1 Developing transfer standards for angular vibration comparison calibration Ultra-precision rotary encoders Upgrade the frequency calibration range: Angle-prism based laser interferometer Frequency range: 0.4 Hz ~ 1 khz Angular displacement: 30 Developing 2 nd generation system for primary linear/angular vibration calibration: New differential plane mirror interferometer (DPMI) system New dynamic displacement measurement module (16-bit-ADC + FPGA) for DPMI Targeted to integrate linear and angular calibration systems into one unit 8

9 Thank you!