RU1835614C - Method of determining electroacoustic transducer parameters - Google Patents

Description

The invention relates to instrumentation and can be used to determine the parameters of electro-acoustic transducers during their development and manufacture.

An object of the invention is to increase the accuracy of the determination of the parameters of an electro-acoustic transducer.

To achieve this goal in a method for determining the parameters of an electro-acoustic transducer, which consists in rigidly securing a controlled electro-acoustic transducer on the working surface of the vibrostand, mechanically exciting the vibro-stand working surface by applying a harmonic voltage to it of a given frequency f and amplitude U, and measuring the vibrational velocity of the working surface of the vibro-stand Vn at a given

frequency and calculation of the mechanical impedance of the monitored electro-acoustic transducer, before rigidly mounting the monitored electro-acoustic transducer on the working surface of the vibrostand, additionally mechanically excite the working surface of the vibrostand by supplying it with a voltage of a given frequency f and amplitude U, and the value of the vibrational working speed is measured in series

vibro-stand surfaces in idling V and when loaded with a tared load Vm. and the mechanical impedance of the controlled electro-acoustic transducer at a given frequency is determined from the expression

00 Сл)

with about

J wm ()

7 -

,

$ -. -)

de w 2 l: f - circular frequency;

m is the mass of the calibrated cargo.

The mechanical resistance of an electro-acoustic transducer, by definition, is the ratio of the force acting on the element of the working surface of the transducer to the speed of movement of this element. A direct determination of the mechanical resistance of the transducer is very difficult and, in some cases, impossible. In order to measure the exciting force and vibrational velocity on the working surface of the transducer. But fixing any sensors on the working surface of the transducer distorts the shape and amplitude of oscillations of this transducer surface. During mechanical excitation of the controlled transducer on a vibrating stand, provided that it is rigidly fixed. The mechanical impedance of a loaded vibrating stand will be determined by the mechanical impedance of the monitored transducer. By knowing the value of the internal resistance of the vibrating stand, it is possible to rather easily and with any degree of accuracy determine the mechanical impedance of the controlled transducer at a given frequency. In this case, the vibrosted should be excited at a given frequency f by a harmonic electric voltage with a constant amplitude U.

The drawing shows a structural diagram of a device that implements the method.

A method for determining the mechanical impedance of an electro-acoustic transducer is carried out as follows.

Using a generator of electrical signals 1, a vibration stand 2 mechanically excites a controlled electro-acoustic transducer 3 by a harmonic voltage of constant amplitude at a given frequency. Using a vibration sensor 4, mounted on the working surface of the vibrostand, and a vibration measuring unit 5, the value of the vibrational velocity / p of the working surface of the vibrostand loaded with a controlled transducer is measured, then the value of the vibrational velocity of the working surface of the vibrostand Vm loaded with a calibrated load t is measured, and the value of the vibrational speed V of the working surface

and

Yes, in the mode of his idle head. Mechanical impedance of a controlled electro-acoustic transducer

determined by the formula:

10

Z

(-1)

Ј

fifteen

twenty

25

thirty

35

40

45

fifty

Claims (1)

Due to the absence of distortion in the shape and amplitude of oscillations of the working surface of the transducer when measuring the exciting force and vibrational velocity of this surface, an increase in the accuracy of determining the parameters of the electro-acoustic transducer is achieved. SUMMARY OF THE INVENTION A method for determining the parameters of an electro-acoustic transducer, which consists in rigidly securing a controlled electro-acoustic transducer on the working surface of the vibrostand, mechanically exciting the vibro-stand working surface by applying harmonic voltage to it of a given frequency f and amplitude U, measuring the vibrational velocity of the working surface of the vibrostand Vn at a given frequency and calculating mechanical impedance controlled electro-acoustic transducer l, characterized in that, in order to improve accuracy, before rigidly mounting the monitored electro-acoustic transducer on the working surface of the vibrostand, the working surface of the vibrostand is additionally mechanically energized by applying voltage of a given frequency f and amplitude U to it and the vibrational velocity of the working surface of the vibrostand is successively measured in idle modes V and when loading it with a tared load Vr, and the mechanical impedance of the controlled electro-acoustic conversion ers at a given frequency is determined from the expressions, 9- jo, m (-1) and Ј-. where O) 2 l f - circular frequency; t-, mass of tared cargo.