JPH02309279A - Receiving system of sonar apparatus - Google Patents

Abstract

PURPOSE:To lessen the number of channels by a system wherein an automatic gain control of an amplifier amplifying a reception signal of each receiving system before the reception signal of each receiver is synthesized in the same phase by a delay circuit network is conducted in accordance with the level of the reception signal inputted to a delay circuit and thereafter the phase of each receiving system is synthesized in the same phase through the delay circuit network. CONSTITUTION:Reception signals from receivers 1 to 3 are detected by amplifying parts of outputs of variable gain amplification circuits 14 to 16 by amplification detection circuits 20 to 22 respectively. Thereafter the maximum output signal in each channel is detected by analog gate circuits 23 to 25, impedance conversion and amplification are conducted in a direct-current amplification circuit 26 of high input impedance, a time constant being suitable for the property of the signal is set by a time constant circuit 27, and thereby the gain of the variable gain amplification circuits 14 to 16 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sound receiving system for a sonar device that emits sound waves into water and uses the reflected waves to detect a target.

[Conventional technology]

The configuration of the automatic gain control circuit in the reception system of a conventional sonar device is such that the reception signal from the receiver is once amplified by an amplifier circuit, and the reception signal output of each receiver is synthesized in the same phase by a delay circuit network. Automatic gain control was performed on the received output of each receiver. Therefore, as the number of output channels of the above-mentioned delay circuit increases, the number of channels on which automatic gain control is performed also increases, making it difficult to match the characteristics of each channel, and increasing the number of parts used, making the configuration complex. There was a drawback.

In addition, since the range of change in the input level of the delay circuit becomes wider depending on the received sound pressure level, if the delay circuit is configured with a digital circuit, it will not work well unless the number of bits of the A-D converter is increased. I couldn't get the performance. The conventional system will be briefly explained according to the block diagram of FIG. In Figure 2, 1 to 3 are receivers, 4 to 6 are amplifier circuits, and 7
is a delay circuit, 8 to 10 are variable gain amplifier circuits, and 11 to 13 are
is a control circuit, in which the received signals from the wave receivers 1 to 3 are amplified by amplifier circuits 4 to 6, and then input to a delay circuit network 7.

After this, in the delay circuit network 7, the received signals of each receiver are all synthesized in the same phase by calculating the difference in the arrival time of the signal to each receiver that occurs with respect to a certain reference plane, and passing it through a delay element such as C. do.

The output signal of the delay circuit network 7 is output from variable gain amplifier circuits 8 to 1.
A part of the output of the variable gain amplifier circuit is input to the control circuits 11 to 13 to create a control voltage and perform automatic gain control, so that the output level of the variable gain amplifier circuits 8 to 10 is constant against reverberation. It works so that it becomes.

[Problem to be solved by the invention]

The range of change in the input level of the conventional delay circuit described above is
Since the width increases depending on the received sound pressure level, when the delay circuit network is configured with a digital circuit, good characteristics cannot be obtained unless the number of bits of the A-D converter is increased.

Furthermore, the characteristic of the amplifier circuit provided after the delay circuit network is that a wide input/output linearity range is required, resulting in the disadvantage that the configuration of the vibration receiving system becomes complicated, large, and expensive.

An object of the present invention is to eliminate the problems of the prior art described above, and to enable a vibration receiving system to be configured simply and at low cost.

[Means to solve the problem]

The object of the invention is to provide an amplification and detection circuit that amplifies and detects a part of the output of a variable gain amplifier circuit, an analog gate circuit that detects the maximum output signal in each channel, a DC amplifier circuit that performs impedance conversion and amplification, and a signal and a time constant circuit that sets a time constant suitable for the characteristics of the variable gain amplifier circuit, the gain of which is controlled by the output voltage of the time constant circuit. This is achieved by automatically controlling the gain before combining the received signals of each receiver in the same phase using a delay circuit network.

[Effect]

According to the reception method of the sonar device of the present invention, before combining the reception signals of each receiver in the same phase using a delay circuit network, an amplification consideration circuit performs automatic gain control of an amplifier that amplifies the reception signals of each reception system. After this is done according to the received signal level input to the delay circuit via the analog gate circuit, DC amplifier circuit, and time constant circuit, the phase of each receiving system is synthesized in the same phase through the delay circuit network. The number of channels that perform gain control can be reduced, and the range of change in the input level of the delay circuit network can be reduced.

〔Example〕

FIG. 1 shows an embodiment of the present invention, and shows an example of gain control based on the maximum output signal level in each channel.

As shown in FIG. 1, the vibration receiving system of the sonar device of the present invention includes variable gain amplifiers 14 to 16 provided between each output of the receivers 1 to 3 and a delay circuit y47.
6 shows the output of each of the amplifiers, and amplification examination circuits 20 to 22,
The outputs of the analog gate circuits 23 to 25 are respectively added to the DC amplifier circuit 26 and the outputs are added to the DC amplifier circuit 26 via the time constant circuit 27. The amplifiers 17 to 19 provided at the outputs are configured so as not to perform gain control.

The vibration receiving system of the sonar device of the present invention is constructed as described above, and the operation of this system will be described below.

Now, the received signals from the transfer devices 1 to 3 are amplified by the variable gain amplifier circuits 14 to 16 and then applied to the delay circuit network 7. At this time, after a part of the output of the variable gain amplifier circuits 14 to 16 is amplified and detected by the amplification and detection circuits 20 to 22, respectively, the maximum output signal in each channel is detected by the analog gate circuits 23 to 25, and the high human power impedance is detected. DC amplifier circuit 2
6 performs impedance conversion and amplification, and time constant circuit 2
In step 7, a time constant suitable for the characteristics of the signal is set to control the gains of the variable gain amplifier circuits 14 to 16. In this method,
The maximum value of the output signal level of the variable gain amplifier circuits 14 to 16 becomes constant, and the level difference of the human input signal between channels directly appears as a difference in the output signal level. The delay circuit M47 calculates the difference in signal arrival time to each receiver that occurs with respect to a certain reference plane, and by passing it through a delay element such as C, the received signal outputs of each receiver are all combined in the same phase, and the output is are respectively amplified by amplifier circuits 17 to 19 and sent to the next stage.

〔Effect of the invention〕

According to the reception method according to claim 1, the number of channels for automatic gain control can be reduced, and the range of change in the input level of the delay circuit network can be reduced, so that the reception signal output of each receiver can be digitally synchronized. Even if the number of bits of the A-D converter is smaller when converting into phase, the same performance can be obtained. Furthermore, the input/output linearity range of the amplifier circuit provided after the delay circuit network is not required to be large.

Incidentally, if this method is used, there are many advantages such as the ability to economically manufacture a vibration receiving system including an amplifier circuit, a delay network automatic gain control circuit, and the like in a small size.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a method of configuring an automatic gain control circuit according to the present invention, and FIG. 2 is a block diagram illustrating a method of configuring a conventional automatic gain control circuit. 1-3... Delivery device, 4-6. 17-19... Amplifier circuit, 7... Delay circuit network, 8-10. 14-16...
Variable gain amplifier circuit, 11-13... control circuit, 20-
22... Amplification detection circuit, 23-25... Analog gate circuit, 26... DC amplifier circuit, 27... Time constant circuit. Patent applicant Hitachi Shonan Electronics Co., Ltd. Agent Patent attorney Masami Akimoto (1 other person)

Claims (1)

[Claims] 1. When emitting sound waves into the water and detecting a target using the reflection of the sound waves, an amplification/detection circuit that amplifies and detects a part of the output of the variable gain amplifier circuit, and a maximum output signal in each channel are used. Equipped with an analog gate circuit for detection, a DC amplifier circuit for impedance conversion and amplification, and a time constant circuit for setting a time constant suitable for the characteristics of the signal,
An automatic gain control circuit consisting of the variable gain amplifier circuit whose gain is controlled by the output voltage of the time constant circuit is placed in front of the delay circuit network, and the received signals of each receiver are synthesized in the same phase by the delay circuit network. A vibration reception method for a sonar device that is characterized by automatic gain control before the sonar device.