JPS5831093Y2 - Sonar device vibration receiving circuit - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a receiver circuit for a sonar device that emits sound waves underwater and uses the reflected waves to detect a target.

Conventionally, the configuration of the automatic gain control circuit in the reception system of a sonar device was to first amplify the reception signal from the receiver using an amplifier circuit, and then combine the reception signal outputs of each receiver with the same phase using a delay circuit network. Automatic gain control is performed on the received output of each receiver using the later received output.

In general, in a nonar, the number of output channels of the delay circuit network is greater than the number of input channels in order to finely divide the display of the azimuth direction and obtain a detailed screen.

Conventionally, as mentioned above, an automatic gain control circuit was provided after the delay circuit network that synthesized all the received signal outputs of each receiver at the same position, so the output of the delay circuit network described above had a large number of channels. There are a large number of channels that require automatic gain control (so it is difficult to align the characteristics of each channel,
Another disadvantage is that the number of parts used increases and the configuration becomes complicated.

In addition, the range of change in the input level of the delay circuit becomes wider depending on the received sound pressure level, so if the delay circuit is configured with a digital circuit, good performance will be achieved unless the number of pins in the A-D converter is increased. I couldn't get it.

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

The purpose of the present invention is to eliminate the drawbacks of the prior art described above, and its feature is that automatic gain control is performed before all received signal outputs of each receiver are combined in the same phase using a delay circuit network. This is what I did.

First, a conventional circuit will be briefly explained according to the block diagram of FIG.

In Fig. 1, 1.2.3 is a receiver, 4, 5.6 is an amplifier, 7 is a delay circuit, 8, 9.10 is a variable gain amplifier circuit, and 1L12, 13 is a control circuit. Wave device 1, 2.
The oscillation signal from 3 is amplified by amplifier circuits 4, 5.6 and then input to delay circuit network 7.

In the delay circuit network I, the difference in signal arrival time to each receiver that occurs with respect to a certain reference plane is calculated, and by passing through a delay element such as C, the received signals of each receiver are all synthesized in the same phase.

The output signal of the delay circuit network 7 is the variable gain amplifier circuit a, s.
, io, and a part of the output of the variable gain amplifier circuit is input to the control circuits 11, 12 and 13 to create a control voltage and perform automatic gain control, and the variable gain amplifier circuit 8
, 9°100 so that the output level remains constant.

However, this circuit system has the above-mentioned problems.

Next, the present invention will be explained in detail with reference to FIGS. 2 to 5.

FIG. 2 is a block diagram of an automatic gain control circuit showing an embodiment of the present invention, and as shown in the figure, the received signal from the wave receiver 1.2. After being amplified at 16, it is applied to delay network 7.

At this time, a part of the outputs of the variable gain amplifier circuits 14, 15, 16 are input to the control circuits 17, 18, 19, and automatic gain control is performed for each variable gain amplifier circuit 14, 15, 16.

As a result, the output level of each variable gain amplifier circuit 14, 15, and 16 is controlled to be constant against reverberation.

In the delay network I, the difference in signal arrival time to each receiver that occurs with respect to a certain reference plane is compensated for by passing through delay elements such as C, and the received signal outputs of each receiver are all combined at the same position. Then, the blades are transmitted to amplifier circuits 20, 21 . 22 and sends it to the next stage.

According to this configuration, various problems in the prior art described above can be solved, and a dynamic range can be increased.

Further, FIG. 3 shows a second embodiment of the present invention, and is an example in which gain control is performed according to the maximum output signal level in each channel.

The received signal from the receiver 1.2.3 is amplified by the variable gain amplifier circuit 14.15.16 and then applied to the delay network γ.

At this time, a part of the output of the variable gain amplifier circuit 14, 15, 16 is amplified and detected by the amplification detection circuit 23, 24, 25, and then the maximum output in each channel is detected by the analog gate circuit 26, 27, 28. The signal is detected, the high input impedance DC amplifier circuit 29 performs impedance conversion and amplification, the time constant circuit 30 sets a time constant suitable for the characteristics of the signal, and all variable gain amplifier circuits 14, 15, 16 Control gain.

According to this method, the maximum value of the output signal level of the variable gain amplifier circuits 14, 15, and 16 becomes constant, and the level difference in the input signal between channels directly appears as the difference in the output signal level.

Then, in the delay circuit network 7, by calculating the difference in signal arrival time to each receiver that occurs with respect to a certain reference plane, and passing it through a delay element such as C, the received signal output from each receiver is all in the same phase. The output is amplified by the amplifier circuit 20.2L22 and sent to the next stage.

In this circuit system as well, since the gain control of each variable gain amplifier circuit is performed before the delay circuit network 7, a large dynamic range can be achieved.

Furthermore, FIG. 4 shows a third embodiment of the present invention. In the second embodiment, the gain was controlled by the maximum output signal level in each channel, but in this embodiment, the gain was controlled by the average output signal level of each channel. This is an example of gain control based on signal level.

The received signal from the receiver 1.2.3 is sent to the variable gain amplifier circuit 1.
After being amplified at 4.15.16, it is applied to the delay network 7.

At this time, after a part of the output of the variable gain amplifier circuit 14°15.16 is amplified and detected by the amplification/detection circuits 23 and 24°25, the average value of the output level of each channel is calculated by the average value circuits 31 and 32°33. The high input impedance DC amplifier circuit 29 performs impedance conversion and amplification, and the time constant circuit 30 sets a time constant suitable for the characteristics of the signal to adjust the gains of all variable gain amplifier circuits 14, 15, and 16. The idea is to control the

Although the average value circuit using resistors has been described here, it can also be performed by adding the outputs of each channel using an analog adder and then dividing the result using a divider such as a resistor.

It is also possible to digitalize the average value circuit and perform automatic gain control digitally.

As mentioned above, according to the receiver circuit of the sonar device according to the present invention, an automatic gain control circuit is provided before the delay circuit network, and before the delay circuit network synthesizes the receiver signals of each receiver in the same phase. Since the configuration is configured to perform automatic gain control, if the number of channels from the delay circuit network to the receiver side is smaller than the number of channels from the delay circuit network to the output amplifier circuit side, the number of channels for which automatic gain control is performed is small. Done,
In addition, since the range of change in the input level of the delay circuit network can be reduced, when digitally setting the received signal output of each receiver in the same phase, the same performance can be achieved even if the number of bits of the A-D converter is reduced. You can get it.

Furthermore, the input/output linearity range of the amplifier circuit provided after the delay circuit network is not required to be large.

Furthermore, the present invention has many advantages such as being able to economically produce a vibration receiving system including an amplifier circuit, a delay circuit, and an automatic gain control circuit 2 in a small size. You can get it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining a conventional method of configuring an automatic gain control circuit, and FIGS. 2 to 4 are block diagrams showing embodiments of a method of configuring an automatic gain control circuit according to the present invention.
Figure 2 is an example of automatic gain control for each channel, Figure 3 is an example of gain control based on the maximum output signal level of each channel, and Figure 4 is an example of automatic gain control based on the average output signal level of each channel. This is an example of performing gain control. 1-3...Receiver, 4-6, 20-22...
... Amplifier circuit, 1 ... Delay circuit network, 8 to 10
．． 14-16...Variable gain amplifier circuit, 11-1
3.17-19...control circuit, 23-25...
...Amplification detection circuit, 26-28...Analog gate circuit, 29...Direct current amplifier circuit, 30
...Time constant circuit, 31-33...Average value circuit.

Claims (1)

[Scope of utility model registration request] This is an oscillation circuit for a sonar device that emits sound waves into the water and uses the reflection of the sound waves to detect targets.It includes multiple receivers and amplifies the received signal obtained through the receivers. a variable gain amplifier circuit, a delay circuit for combining the received signal outputs obtained through the variable gain amplifier circuit in the same phase, and an amplifier for amplifying the received signal outputs synthesized in the same phase through the delay circuit. circuit, and a stage preceding the delay circuit for controlling the output level of the variable gain amplifier circuit to be constant with a time constant suitable for the nature of the signal, using a part of the output of the variable gain amplifier circuit as an input. and a control circuit provided in the sonar device, wherein the sonar device is configured to automatically perform gain control in a stage before combining the received signal outputs of each receiver in the same phase using the delay circuit. Receiver circuit.