Abstract
The device described here basically measures the radiation impedance of a thin circular membrane. The membrane is excited by a push-pull electrostatic drive, and its velocity is determined by a carrier capacitance measurement method. The force applied divides between the air on both sides and the membrane itself. One side is terminated in a reflectionless chamber, and the unknown is presented to the other side. The ratio of potentials proportional to force and velocity give total impedance from which the unknown can be determined. When pressure is measured by a microphone, specific impedance is measured and compensation for the membrane and terminated side is not necessary. However, the separation of the membrane and microphone results in a phase error. The characteristics and limitations of the device are presented and some measurements given. Some application to room acoustics and sound-reproducing systems are suggested. [Supported in part by the Office of Naval Research.]
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
