SU1615789A1 - Method of shaping sine acoustic signals - Google Patents

Abstract

The invention relates to acoustics and can be used in studies of the propagation of acoustic waves in various media. An in-phase, rectangular-shaped electric pulses with a duty cycle of two, the acoustic signals are directed and concentrated in a given region of space. The use of certain ratios of operating frequencies, amplitudes and the total number of acoustic transducers provides for the expansion of the frequency range of the generated sinusoidal acoustic signals.

Description

The invention relates to acoustics and can be used in studies of the propagation of acoustic waves in various media.

The purpose of the invention is to expand the frequency range of the generated sinusoidal acoustic signals.

The method of generating acoustic signals of a sinusoidal shape is to use N acoustic transducers, which are simultaneously excited by rectangular electric pulses with a duty cycle of two. All acoustic signals are directed and concentrated in a given region of space. In order to obtain the required sinusoidal acoustic signal in a given area of space, the working frequencies, amplitudes and number of transducers must satisfy the following relations: fk (2k-1) .fi, t All

lAkl

2k-1

N fe-1

the polarity of the in-phase electrical pulses is chosen from the conditions

Ak Oh, if 2k-1 j; Ak Oh, if 2k-1 (2i - l); Ak 0, ecli2k-1 ji2k-1- (2i-1) .r. where k is the sequence number of the converter;

i is a natural number;

J is a prime number;

f is the frequency of the acoustic signal;

A is the amplitude of the acoustic signal;

fa is the upper limit frequency of the passband of the path for the formation and propagation of an acoustic signal.

Corresponding electrical acoustic signals are concentrated in a predetermined region of space with preservation of the initially predetermined ratio of the phases of the signals. As a result, the spurious harmonics contained in the original acoustic signals generated by rectangular pulses are compensated. This compensation is performed up to the 105th harmonic.

ON

..iji

SL

Xj

00

YU

formed as a result of a sinusoidal acoustic signal. When the ratio fe 105 fi is fulfilled, the distortion of the sinusoidal waveform is entirely determined by the degree of accuracy of the concentration of the original signals, i.e. accuracy of preservation of the initially specified phase ratio of signals.

Claims (1)

The proposed method allows the generation of acoustic signals of a sinusoidal shape in a wide frequency range in a given area of space. Claim method A method of forming a sinusoidal acoustic signals, according to which an acoustic transducer is excited by rectangular electric pulses with a duty cycle of two, characterized in that, in order to expand the frequency range of the acoustic signals, the N - 1 transducers and all acoustic signals are concentrated in a given region of space, while the operating frequencies, amplitudes and number of N transducers are stealing the relations fk (2k-1) .fi, Iam -iAlJ 2k-1 N t The ITa polarity of the common-mode electrical pulses is chosen from the conditions Ak Oh, if 2k -1 J, Ak Oh, if 2k-1 (21-1). D Ak Oh, ecli2k-1 ijm2k-1 (). F where k is the sequence number of the converter; f is the frequency of the acoustic signal; A is the amplitude of the acoustic signal; ffl is the cutoff frequency of the bandwidth of the path for the formation and propagation of the acoustic signal; j is a prime number; I is a natural number.