JP2867417B2 - Passive sonar signal simulator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passive sonar signal simulator, and more particularly to a non-spike that generates a ship, which is necessary in training for improving the skill of an operator of the passive sonar device. The present invention relates to a passive sonar signal simulating apparatus for simulating a broadband acoustic signal.

[Conventional technology]

Conventionally, in this kind of passive sonar signal simulator, a broadband signal simulator that simulates a broadband having a band generated by a ship is a simple white noise generator.

[Problems to be solved by the invention]

Broadband signals of actual ships vary in level and frequency spectrum distribution depending on the operation of the ship,
In the conventional broadband signal simulation circuit described above,
Since the frequency spectrum distribution cannot be changed, there is a drawback that training according to the actual situation cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a passive sonar signal simulator which generates a broadband signal whose frequency spectrum distribution is simulated in correspondence with the actual broadband signal of an actual ship and eliminates the above-mentioned drawbacks, and which can be trained in accordance with the actual situation. Is to do.

[Means for solving the problem]

A passive sonar signal pseudo signal of the present invention is a spectrum distribution generating circuit that generates a spectrum distribution signal in a frequency domain expressing an arbitrary spectral distribution of an acoustic signal generated by a ship, a white noise generating circuit that generates white noise, A characteristic variable filter that receives the spectral distribution signal, variably imparts a frequency characteristic corresponding to the frequency characteristic, receives the white noise, and generates a passive sonar pseudo signal simulating the sound generated by the ship. It is composed.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a passive sonar signal simulator according to the present invention. The embodiment of FIG. 1 includes a spectrum distribution generating circuit 1 for generating a spectrum distribution signal in a frequency domain expressing an arbitrary spectral distribution of an acoustic signal generated by a ship, a white noise generating circuit 2 for generating white noise, A passive sonar simulating the sound generated by a ship in response to a spectrum distribution signal generated by a spectrum distribution generating circuit and variably assigned a frequency characteristic corresponding to the frequency characteristic thereof and receiving white noise output from the white noise generating circuit 2 A characteristic variable filter 3 for generating a pseudo signal.

 Next, the operation of the embodiment shown in FIG. 1 will be described.

The spectrum distribution generating circuit 1 sets a desired broadband signal of a ship to be simulated, and supplies the broadband signal to the characteristic variable filter 3 as a frequency domain spectrum distribution signal 101 by Fourier transform.

The characteristic variable filter 3 receives the input spectrum distribution signal.
An inverse Fourier transform circuit 31 for performing an inverse Fourier transform on 101 to obtain an impulse response signal 301;
And a finite impulse response filter 33 formed by using the filter coefficient 32 and driven by the white noise 21.

The spectrum distribution signal 101 is frequency domain data representing the frequency spectrum distribution of the broadband signal. The inverse Fourier transform circuit performs an inverse Fourier transform on the spectrum distribution signal 101 and outputs an impulse response signal 301 in the time domain. The impulse response signal 301 has a frequency characteristic equivalent to that of the spectrum distribution signal 101 and is equal to the impulse response of a special filter, based on the principle of the inverse Fourier transform.

The window function multiplying circuit 32 generates the impulse response signal 30
1 is multiplied by a window function such as a Hanning window function to perform cutout with ripple suppressed, and output a filter coefficient 302.

The above-described multiplication of the window function is a necessary process for suppressing the ripple of the frequency characteristic of the characteristic variable filter 3, and may be omitted when the ripple characteristic is not emphasized.

The finite impulse response type filter 33 is a finite impulse response type filter (FIR filter) formed by receiving the output of the window function multiplication circuit 32 as a filter coefficient corresponding to the sample point and forming it as a filter coefficient. It has a frequency response characteristic equal to 101. The white noise signal 201 is supplied to the finite impulse response filter 33, and as a result, a passive sonar pseudo signal 303 having a spectrum distribution corresponding to the frequency spectrum distribution of the broadband signal generated by the ship is generated.

In this case, the spectrum distribution given to the spectrum distribution signal 101 can be set arbitrarily, and thus a passive sonar pseudo signal having an arbitrary spectrum distribution can be obtained.

〔The invention's effect〕

As described above, the present invention changes the frequency spectrum distribution of a passive sonar pseudo signal to simulate an acoustic signal generated by a ship to a content according to the operation status of the ship, thereby producing a passive sonar signal based on the actual situation. Simulating is possible, and there is an effect that the training effect can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of one embodiment of a passive sonar signal simulation apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Spectrum distribution generation circuit, 2 ... White noise generation circuit, 3 ... Characteristic variable filter, 31 ... Inverse Fourier transform circuit, 32 ... Window function multiplication circuit, 33 ... Finite impulse response type filter.

Claims (1)

(57) [Claims] 1. A spectrum distribution generating circuit for generating a spectrum distribution signal in a frequency domain expressing an arbitrary spectrum distribution of an acoustic signal generated by a ship, a white noise generating circuit for generating white noise, and A characteristic variable filter that receives the white noise and generates a passive sonar pseudo signal simulating the sound generated by the ship by receiving the white noise variably. Passive sonar signal simulator.