JPH0210473Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an acoustic device for acoustically notifying the presence of a school of fish in a fish finder.

[Conventional technology]

In a fish finder that detects a school of fish using a received echo signal obtained by transmitting an ultrasonic pulse and receiving a reflected wave, the received echo signal is converted into sound, and the presence of a school of fish is notified by the sound. Acoustic equipment for fish finders is based on Utility Model Publication No. 46-32384, etc.
Further, a configuration for changing the acoustic frequency of the sound depending on the depth is well known from Japanese Utility Model Publication No. 55-35582.

[Problem that the invention attempts to solve]

The above configuration that changes the acoustic frequency depending on the depth uses the height of the acoustic frequency to determine whether the received echo due to the reflected wave from the detected object is suitable for the target school of fish or the conditions on the sea floor. It has the advantage of being able to be known and is extremely convenient, but it is not possible to use a system that simply changes the acoustic frequency in a linear or curved manner in response to depth.
Since the acoustic frequency changes even during the reception echo period, it is difficult to hear the sound at a constant acoustic frequency, which poses a problem in that it becomes difficult to distinguish between the depths at which the reception echoes are obtained.

In other words, in the above case, the change in acoustic frequency changes only in one direction with depth,
For example, if a shallower sound has a lower frequency, the sound will gradually change to a higher frequency as the depth increases.

By the way, most fish finders are provided with a large number of depth ranges to detect, that is, ranges, and are designed to select and use the range that matches the depth of the school of fish.

On the other hand, since the water temperature and current change with respect to depth, day and night, and the season, the habitat of fish schools also changes in depth, so it is necessary to select and use a range that is commensurate with this.

In addition, since the human ear is not very sensitive to very low and very high sounds, in the case of the cited example, the maximum range of the fish finder, for example, the range of 0 to 1000 m. 200~3000Hz
It will be set so that the scale slope is as follows.
In this case, the range of change in acoustic frequency is proportional to the detection depth, so the slope of the scale for the 0-100m range is
This results in a small variation range of 200 to 300Hz,
In addition to reducing the resolution of the scale relative to depth, if there is a fish echo with a relatively wide width, the sound will change and sound as if it is "rising" due to changes in the acoustic frequency. This causes the inconvenience that it becomes difficult to distinguish between sounds depending on depth.

Therefore, in order to avoid this, the depth range is 0~
Acoustic frequency range from 200 to 2000 for 100m range
It is conceivable to increase the slope of the scale with respect to depth, such as setting it to Hz, but in this case, from 0 to
Acoustic frequency for 1000m range is 200~10000Hz
As a result, for example, the acoustic frequency at 800 to 1000 meters becomes too high, resulting in the inconvenience that the human ear cannot hear it due to its sensitivity. One possible way to avoid this inconvenience is to set the frequency to 200 to 2000 Hz in all ranges, but this method requires that the voltage slope corresponding to depth be different for all ranges. Therefore, it is necessary to provide a large number of switching circuits and charging time constant circuits corresponding to the number of ranges, which results in a complicated configuration and the disadvantage that it cannot be provided at a low cost.

[Means for solving problems]

The present invention combines the configuration for changing the acoustic frequency with a voltage change that is changed by the output of a counter that starts counting by a transmission timing pulse, and a voltage frequency conversion means that changes the frequency in accordance with this voltage change. The clock for counting is gated using a signal obtained by waveform-shaping the received echo signal of a school of fish, thereby stopping the voltage change described above, and making an acoustic notification by keeping the voltage constant only during that time. By providing a means for keeping the above-mentioned frequency constant, when a received echo is obtained, it is possible to notify with a sound of a constant tone corresponding to the depth,
This is designed to solve the above problems.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is a transducer, 2 is a transceiver switching circuit, and when transmitting, a transmission timing pulse generator 4 is shown.
The electrical signal generated by the transmitter 3 by the output of
The ultrasonic pulses are converted into ultrasonic pulses by the transducer 1 through the transmission/reception switching circuit 2 and emitted into the water.

Ultrasonic waves reflected by schools of fish in the water are
The wave is received again by the transducer 1, converted into an electrical signal, and sent to the receiving section 7 through the transceiver switching circuit 2.

The above devices are the same as the transmitter/receiver in a conventional fish finder, but the present invention uses the transmitting timing pulses and receiving output signals of these devices to identify target schools of fish and other fish at specific depths. This is an acoustic device in a fish finder that allows you to distinguish between things that exist at depth.

The transmission timing pulse generator 4 goes to the transmission unit 3 and also goes to the time voltage generation circuit 5 to generate a voltage that is proportional or inversely proportional to the depth.

On the other hand, the output signal of the receiving section 7 is shaped into a desired waveform by a waveform shaping circuit 8, and then sent to a modulator 9.
is given to the time voltage generation circuit 5.

There are two methods for keeping the output voltage of the time voltage generating circuit 5 constant only during the period when the reflected signal exists: the method shown in FIG. 2 and the method shown in FIG. 3.

The output voltage of the time voltage generation circuit 5 is added to the voltage frequency signal conversion circuit 6, which generates a frequency signal according to the voltage (depth), and supplies it to the modulator 9, which modulates the output signal of the waveform shaping circuit 8, and reflects the signal. A signal with a constant frequency component corresponding to the depth is created only during the period when the signal exists.

This signal is amplified to a required level by an amplifier 10, and a voltage-acoustic transducer 11 such as a loudspeaker is configured to generate sound.

FIG. 2 shows an embodiment in which the voltage is kept constant only during the period when the received echo exists, but the voltage at the time the received echo occurs and the voltage immediately after the received echo disappears are the same.

From the time of generation of the transmission timing pulse a shown in 1 in FIG.
3 passes through the gate 14 and starts up-counting, and the output voltage of the DC voltage amplifier 16 begins to rise.

On the other hand, during the period when the output signals b and c of the waveform shaping circuit 8 shown in 2 in FIG. 4 are present, the gate 14 is closed by the output signals d and e of the comparator 12 shown in 3 in FIG. Clock generation circuit 1
The output of the DC voltage amplifier 16 is not input to the counter 15, and the output voltage of the DC voltage amplifier 16 is kept constant. The output voltage is as shown at 4f in FIG.

In Fig. 3, it is the same as in the embodiment shown in Fig. 2 that a constant voltage is maintained only during the period when the received echo exists, but the voltage at the time the received echo occurs and the voltage immediately after the received echo disappears are different. There are differences from the embodiment shown in FIG.

In other words, the difference from FIG. 2 is that a presettable counter is used as the counter 19, and immediately after the received echo disappears, the value of the counter 20, which operates regardless of the existence of the received echo, is transferred to the counter 19. 5. The voltage is loaded at the timing of the differential pulse generation circuit output signals g and h shown in FIG. 4, and the voltage is restored as if there were no received echo. The output voltage is as shown in 5i in FIG.

In the embodiment shown in FIG. 2, the output voltage of the DC voltage amplifier 16 becomes more difficult to rise as the number of received echo samples increases, but in the embodiment shown in FIG. 3, the same depth is always supported regardless of the number of received echo samples. A frequency signal is obtained.

2 and 3 show an example in which the DC voltage amplifier 16 rises over time, but if the counter group is used as a down counter or the DC voltage amplifier 16 is inverted amplification, the voltage rises over time. It is also possible to have a characteristic in which the voltage decreases as time passes.

By this, the voltage frequency signal conversion circuit 6
By keeping the characteristics constant, it is possible to switch between generating a higher sound as the depth increases, or, conversely, generating a lower sound as the depth increases.

In addition, by adjusting the gain of the DC voltage amplifier 16 with the amplification gain adjuster 17, it is possible to vary the acoustic frequency of the acoustic output, and at the same time, it is possible to vary the acoustic frequency of the acoustic output. When targeting only fish species in shallow waters, it is possible to correct for problems such as the acoustic frequency of the reflected echo being too low.

In order to be able to switch between generating a higher sound as the depth increases, or conversely generating a lower sound as the depth increases, as described above, the time voltage generation circuit 5 must be Switch the counter from a normal counter (in other words, an up counter) to a down counter, or
Alternatively, a function for switching the DC voltage amplifier 16 from normal amplification to inverting amplification, that is, a switching means 6' (not shown) is provided, and this can be selectively switched according to the purpose, such as the type of fishing ground to be detected. It's a good thing.

[Effect of idea]

According to the present invention, as described above, the change in acoustic frequency with respect to depth is made constant only during fish echoes by using a very simple configuration in which the gate of the clock signal applied to the counter is closed only during fish echoes. Since the above-mentioned "rising" sound does not occur, even if the range of change in scale frequency corresponding to the detection range width cannot be large,
It has the advantage of being able to provide an inexpensive device that makes it possible to clearly hear differences in musical scales depending on depth.

[Brief explanation of drawings]

The drawings show an embodiment; FIG. 1 is a block configuration diagram, FIGS. 2 and 3 are specific circuit examples of the time voltage generation circuit, and FIGS. 4, 5, and 5 are examples of main signal waveforms. 1...Transducer/receiver, 2...Transmission/reception switching circuit, 3...
Transmission unit, 4... Transmission timing pulse generator, 5
... Time voltage generation circuit, 6 ... Voltage frequency signal conversion circuit, 7 ... Receiving section, 8 ... Waveform shaping circuit, 9
...modulator, 10 ... amplifier, 11 ... electroacoustic transducer, 12 ... comparator IC, 13 ...
Clock generation circuit, 14... Gate IC, 15...
... Counter IC, 16 ... DC voltage amplifier, 1
7...Amplification gain adjuster, 18...Differential pulse generation circuit, 19...Presettable counter IC,
20... Counter IC, a... Transmission timing pulse, b, c... Waveform shaping circuit output signal, d,
e... Comparator IC output signal, f, i... Time voltage generation circuit output waveform, g, h... Differential pulse generation circuit output signal.

Claims (1)

[Scope of Claim for Utility Model Registration] A fish finder that detects schools of fish using received echo signals obtained by transmitting ultrasonic pulses and receiving reflected waves, wherein the received echo signals are divided into frequencies corresponding to the depth. In the acoustic device for a fish finder, the acoustic device for a fish finder notifies the presence of a school of fish by the sound by converting the sound into a sound that changes and outputs the sound, wherein: a) a signal obtained by shaping the received echo signal by a waveform shaping circuit; a waveform shaping means for outputting a shaped signal; b. applying a clock signal to a counter via a gate, and starting counting in the counter from the time of the transmission timing signal for transmitting the wave, and outputting a count output; c. Counting means for applying the waveform shaping signal to the gate and closing the gate to stop the counting only during the period of the waveform shaping signal; d. time voltage generating means for outputting a signal obtained by applying the signal to a circuit that generates a signal in which the DC voltage increases or decreases as a time voltage change signal; e. a high-voltage frequency means for outputting a signal obtained by applying a signal to a circuit that generates a signal whose frequency increases or decreases as a frequency signal; An apparatus characterized by comprising: acoustic means for obtaining a sound to notify the presence of the school of fish by outputting it.