A Precision Phase Angle Calibration Standard for Frequencies up to 50 kHz

Free-field calibration of the pressure sensitivity of microphones at frequencies up to 80 kHz

A PRECISION CALIBRATION SET-UP FOR AC MAGNETIC FLUX DENSITY MEASUREMENT IN THE RANGE OF 1 Hz TO 20 kHz

A precision generating and measurement system of AC magnetic flux density was developed by using a linear low-frequency AC magnetic field converter, a quartz Helmholtz coil, a voltage comparator, a multimeter, a standard resistor, and a computer with a program for automatic measurement. The expanded uncertainty (k=2) of the calibration system is less than 0.2 % over the frequency range of 1 Hz ...

Calibration of the pressure sensitivity of microphones by a free-field method at frequencies up to 80 khz.

A free-field (FF) substitution method for calibrating the pressure sensitivity of microphones at frequencies up to 80 kHz is demonstrated with both grazing and normal-incidence geometries. The substitution-based method, as opposed to a simultaneous method, avoids problems associated with the nonuniformity of the sound field and, as applied here, uses a 1/4-in. air-condenser pressure microphone ...

Vibration pattern of the organ of Corti up to 50 kHz: evidence for resonant electromechanical force.

Electromechanical force derived from the soma of the outer hair cell has long been postulated as the basis of the exquisite sensitivity of the cochlea. The problem with this postulate is that the electrical source and mechanical load for the electromechanical outer hair cell might be severely attenuated and phase-shifted by the electrical impedance of the cell and the mechanical impedance of th...

An Improved High-Precision Calibration Procedure For Reference Standard Hydrometers

This pape r describes a me thod of calibra ting hydromete rs whic h. a lthoug h no more accurate tha t the technique used he re tofore at the Na tiona l Burea u of S ta nd a rds, reduces calibration time from se ve ral days to a few hours. The p rocedure is based upon eas ily measured h yd rome ter we ight , s tem sca le geometry, and flotat ion leve l measurement s a t onl y one liquid density...