JPH0264488A - Underwater sound dummy signal generator - Google Patents

Abstract

PURPOSE:To obtain a dummy signal having a frequence expanse of every kind by simple constitution by altering the random number value indicated to a random number converter and the value of the generation frequency thereof. CONSTITUTION:A random number generator 11 generates random numbers Rm uniformly to input the same to a random number converter 12 which in turn generates random numbers An according to the random number value indicated from the outside and the generation frequency characteristics thereof on the basis of the control of a random number conversion controller 13. A synthesizer 14 adds the center frequency (f) indicated from the outside to the random numbers An of the random number converter 12. Subsequently, a sine wave generator 15 generates a sine wave of frequency according to the indication of the synthesizer 14. By this method, a dummy signal having a frequency expanse of every kind is obtained by simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an underwater acoustic simulating signal generating device that is a simulating device that simulates a spike signal generated by an underwater sound source.

[Conventional technology]

Conventionally, in this type of underwater acoustic simulation signal generator, the frequency spectrum of a normal underwater acoustic signal is not a fixed single frequency, but is composed of a group of harmonics with a frequency spread characteristic. It simulates individual spike signals with spreading characteristics.

Therefore, as shown in FIG. 4, the conventional underwater acoustic simulation signal generator includes a digital noise generator 41, a digital filter 42, a sample rate converter 43, a digital sine wave generator 44, and a digital amplitude modulator. By changing the characteristics of the digital filter 42, spike signals having various frequency spread characteristics are simulated.

According to this conventional underwater acoustic simulation signal generator, the frequency spread is small compared to the center frequency of the spike signal to be simulated, so the noise generator 41 generates only low frequencies, and the digital filter 42 generates only low frequencies. This is a narrow band low frequency filter that can have specific characteristics according to instructions from the outside in order to simulate the frequency spread characteristics that vary depending on the sound source.

In this way, the digital filter 42 has a low frequency input noise and a low frequency narrow band filter characteristic, so that noise generation and filtering are performed by low frequency sampling. On the other hand, digital sine wave generator 4
Since the center frequency of the signal generated at 4 is high, the sampling is at a high frequency. For this reason, the digital amplitude modulator 4
5, to modulate the high frequency sampled sine wave with the low frequency sampled noise,
Sampling consistency is required. For this reason, the sample rate converter 43 resamples the noise from the digital filter 42 at a high frequency, and performs filtering again so that no extra signal is generated due to sampling.

[Problem to be solved by the invention]

The above-described conventional underwater acoustic simulation signal generation device requires a complicated configuration including a narrow band digital filter and sample rate conversion, and has the disadvantage that the device as a whole becomes large-scale.

An object of the present invention is to provide an underwater acoustic simulation signal generator that eliminates such conventional drawbacks.

[Means to solve the problem]

The present invention provides an underwater acoustic simulating signal generator that simulates a spike signal generated by a sound source that exists underwater, which includes a random number generator that generates random numbers, and a random number that is input from the random number generator and that receives instructions from the outside. a random number converter that generates random numbers according to random numbers and their generation frequency characteristics; a random number conversion controller that controls this random number converter; and a value of the center frequency of a spike signal instructed from the outside and the output of the random number converter. A sine wave generator is characterized in that it is comprised of a synthesizer that synthesizes the signals, and a sine wave generator that generates a sine wave according to the indicated value of the generated frequency that is the output of the synthesizer.

〔Example〕

FIG. 1 is a block diagram of one embodiment of the present invention. This underwater acoustic simulation signal generator includes a random number generator 11, a random number converter 12 which receives a random number as input and generates a random number in accordance with an externally instructed random value and its generation frequency characteristics, and a random number converter 12 which controls the random number converter 12. It is composed of a conversion controller 13, a synthesizer 14 that synthesizes the value of the center frequency of the spike signal instructed from the outside and the output of the random number converter 12, and a sine wave generator 15 that generates an arbitrary frequency. There is.

The random number generator 11 generates random numbers R+++ (m=t, 2.
...M) occurs in a - manner.

The random number converter 12 converts the value of A7 to 87% (n=1°2, .
..., N, ΣB, = 100), the range between the minimum value and the maximum value of random number R1 is 81 to BN.
When the random number R1 assigned to B7 is input, the value of A7 is output.

When simulating a spike signal having a center frequency f and statistical modulus of various frequencies as shown in FIG. is Afi, and the sum of its levels is 1
Individual A, normalized to 00%.

The level of is calculated as Bn%. Here, it is assumed that the reciprocal of the conversion period of the random number is sufficiently small compared to the frequency spread.

The synthesizer 14 receives a center frequency value f instructed from the outside,
The random number A7 which is the output of the random number converter 12 is added.

The sine wave generator 15 simulates a spike signal having the frequency spread shown in FIG. 2 by generating a sine wave according to the instruction value of the generation frequency that is the output of the synthesizer 14.

Next, the operation of this embodiment will be explained.

The random number generator 11 uniformly generates a random number R,%, and inputs this to the random number generator 12. The random number generator 12 generates a random number A7 under the control of the random number conversion controller 13 in accordance with the random number and its generation frequency characteristics instructed from the outside.

The synthesizer 14 adds the center frequency value f instructed from the outside and the random number A7 which is the output of the random number converter 12.

The sine wave generator 15 simulates a spike signal having the frequency spread shown in FIG. 2 by generating a sine wave according to the instruction value of the generation frequency that is the output of the synthesizer I4.

〔Effect of the invention〕

As described above, the present invention has the effect of being able to simulate spike signals having various frequency spreads by changing the random number value instructed to the random number converter and the value of its occurrence frequency.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a diagram showing an example of the spectrum of an acoustic signal to be simulated, Fig. 3 is a diagram showing the output of the random number conversion controller, and Fig. 4 is a conventional device. FIG. 11...Random number generator 12...Random number converter 13...Random number conversion controller I4...Synthesizer 15...Sine wave generator 41...・・Digital noise generator 42・ 43・ 44・ 45・

Claims (1)

[Claims] (1) An underwater acoustic simulating signal generator that simulates spike signals generated by a sound source that exists underwater has a random number generator that generates random numbers, and a random number from this random number generator that is used as input and that receives instructions from the outside. A random number converter that generates random numbers according to random numbers and their generation frequency characteristics, a random number conversion controller that controls this random number converter, and a value of the center frequency of a spike signal instructed from the outside and the output of the random number converter. 1. An underwater acoustic simulation signal generating device comprising: a synthesizer for synthesizing; and a sine wave generator for generating a sine wave according to an instruction value of a generated frequency which is an output of the synthesizer.