JPS64760B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention uses transmission waves such as underwater ultrasound to
The present invention relates to an information transmission device that transmits information such as fishing net detection information.

[Conventional technology]

Such an information transmission device, for example, transmits detection information from a detector placed underwater to a remote receiver as an ultrasonic signal, and receives the waves. There is a fishing net monitoring device that records detection information from the fishnet on the receiving side.

This involves attaching an ultrasonic detector to the net opening of a trawler, detecting the position above and below the net opening from the seabed, etc. as ultrasonic detection information, and transmitting this as another ultrasonic signal. The transmitted signal is received and recorded on the tugboat.

The FM method is generally used for this type of ultrasonic transmission, but when the transmission distance is long, there are methods such as increasing the transmission power or lowering the transmission frequency to a frequency with less attenuation. However, increasing the transmission power consumes a lot of battery power because FM constantly consumes power. Furthermore, if the transmission frequency is lowered, the size of the transformer, which is an ultrasonic wave transmitter, becomes larger, resulting in a size problem.

AM methods are available to compensate for these shortcomings. For example, in a detector, only the detected signal is transmitted.

[Problem that the invention seeks to solve]

In the above method, since waves are transmitted only when there is a detection signal, battery consumption is lower than in the above FM method.

However, compared to the FM method, the AM method generally has a problem in that when reflected signals from the sea surface, the ocean floor, etc. during transmission come in, this directly leads to a deterioration of the S/N ratio.

[Means for solving problems]

In this invention, the information to be transmitted is divided by synchronization signals, the same information is repeated multiple times, and the time length over which the information is distributed each time, that is, the information distribution time length, is different. By providing a transmission means with a different distribution multiple times for transmission, and a correlation means on the receiving side that reshapes the information distribution time length in each of the plurality of transmissions to the same time length and takes a correlation, The above problem is solved by making it possible to remove unnecessary signals such as reflected signals generated by the transmission path.

〔Example〕

An embodiment of the drawings regarding the fishing net monitoring device will be described below.

In FIG. 1, a clock is sent from a reference clock generator 1 to a transmission pulse generation circuit 2, and the transmission pulse in FIG. 3b is separated into upper and lower transmission pulses in FIG. Downward transmitting circuit 2
The signal is amplified by the transducer 6 for upward detection and transmitted by the transducer 4 for upward detection and the transducer 27 for downward detection. The received signal of the reflected echo is amplified and detected by the receiving circuit X5. The waveform is shown in FIG. 3a, and the signal is digitized through the A/D converter 6 and supplied to the memory X10.

On the other hand, before the above-mentioned transmission pulse, a synchronizing signal is generated in the synchronizing signal generating circuit 7 as shown in FIG. 3f. Furthermore, in the synchronization signal generation circuit 7, the synchronization pulses separated in c, d, and i in FIG. 3 are converted into coded pulses named A, B, C, and D in FIG. 3f, for example. .

The memory control circuit 8 in FIG. 1 is supplied with the pulse shown in FIG. 3 c from the synchronization signal generation circuit ₇ , and when the pulse shown in _FIG . , it takes twice as long to read the signal from the memory X10 when the level is low. Address control at this time is performed by the address counter 9.

The digital signal read from the memory X10 is D/A converted and supplied to the switching circuit 12. The switching circuit 12 is controlled by the pulse shown in FIG.
When d is at a low level, the output from the receiving circuit X5 in FIG. 1 is passed through, and when d is at a high level, the output from the memory X10 is passed through. The waveform at that time is shown in FIG. 3e.

Also, although the explanation is confusing, the time from A to B in f in Figure 3 is T ₁ , and from B to C is T ₁ of 2.
_The time from C to D is _T2 , and the time from D to A is twice _T2 , or _2T2 .

After passing through a synthesis circuit 13 that synthesizes the output of the switching circuit 12 shown in FIG. 1 and the output from the synchronization signal generation circuit 7, the signal for transmission becomes the signal shown in FIG. 3j. The combined transmission signal is modulated to a transmission ultrasonic frequency through a modulation circuit 14, amplified through a transmission circuit 15, and transmitted from a transmission transducer 16.

Next, in FIG. 2, the ultrasonic signal transmitted from the transmitting transducer/transducer 16 for transmission shown in FIG.

One of the amplified and detected received signals is an A/D
It is converted into a digital signal by a converter 19, and 1
One is supplied to the synchronization signal detection circuit 20, and synchronization separation is performed as shown in FIG. 3k and l.

Further, a clock is supplied from a basic clock generator 21 to each section. The synchronization-separated synchronization signal is supplied to the memory control circuit 22, which generates the control pulses m and n in FIG. 3, and writes the received signal to the memory Y24 when the level is high as shown in FIG. Reading takes twice as long as writing. At that time, the address control of memory Y24 is performed by the address counter 23.
is given by The signal read from the memory Y24 is supplied to the correlation circuit 25 at the same time as the next received signal and correlated therewith. Memory Y2
The received signal written in 4 is shown in Fig. 3 o, and E in Fig. 3 o is a reflected signal during transmission.

This reflected signal is generally from the ocean floor, sea surface, etc.
The position from the reference position (T ₃ in Figure 3o) always occurs at a constant position each time it is received.

Therefore, as mentioned above, when the signal shown in FIG. 3o is once written into the memory Y24 and read out in twice the time _2T1 , the waveform becomes as shown in FIG. 3q.

Further, the signal following the signal read from the memory Y24 is sent at the same _2T1 . This signal is p in Fig. 3, and the reflected signal E is different from the reflected signal E in Fig. 3 q as shown in the figure.
When the correlation is taken, the reflected signal E is removed as shown in FIG. 3r. Generally, the correlation circuit 25 is composed of a read-only memory, and its output is sent to the D/A converter 28.
and converted into an analog signal.

〔Effect of the invention〕

According to this invention, on the transmission side, the same information divided by synchronization signals A and B (or C and D) is repeatedly transmitted a plurality of times, and the distribution time length of the information is formed to be different each time. On the other hand, unnecessary signals such as reflected signals generated in the transmission path that are mixed in and received with an almost constant delay appear in the received signal each time with an almost constant delay as well. , by re-forming the information distribution time length of each time to the same time length on the receiving side, the delay state of each time is reversely different, so it is erased by taking the correlation, and the intended purpose is not achieved. can be achieved.

In addition, the part where the distribution time length of information is varied or the distribution time length is re-formed to be the same can be simply changed by simply changing the write time and read time of the memory that stores the information. It has the advantage of being able to be configured easily.

[Brief explanation of drawings]

FIG. 1 is an example of a circuit for detecting and transmitting a signal in a seining vessel, and FIG. 2 is an example of a circuit for detecting a signal on the receiving side of a seine vessel. FIG. 3 is a waveform diagram of FIGS. 1 and 2. DESCRIPTION OF SYMBOLS 1...Reference clock generator, 2...Transmission pulse generation circuit, 3...Upper transmission circuit, 4...Upper detection transducer, 5...Reception circuit X, 6...A/D converter, 7...Synchronization signal generation circuit, 8...Memory control circuit, 9...Address counter, 10...Memory X, 11...D/A converter, 12...Switching circuit, 13
... synthesis circuit, 14 ... modulation circuit, 15 ... transmission circuit,
16... Transmission transmitting transducer, 17... Transmitting receiving transducer, 18... Receiving circuit Y, 19... A/D converter, 20... Synchronization signal detection circuit, 21... Reference clock generator, 22... Memory control circuit, 23...Address counter, 24...Memory Y, 25...Correlation circuit, 26...Downward transmission circuit, 27...Downward detection transducer, 28
...D/A converter.

Claims (1)

[Scope of Claims] 1. By transmitting information classified by synchronization signals via a transmission path using transmission waves, and correlating the information obtained by the transmission waves on the receiving side, the transmission An information transmission device configured to remove unnecessary signals such as reflected signals generated by a transmission line, the information transmission device comprising: (a) repeating information with the same content as the divided information multiple times, and repeating the same content in each of the multiple times; (a) a differential distribution multiple transmission means for forming and transmitting information with different time lengths in which the information is distributed (hereinafter referred to as information distribution time lengths); an information transmission device comprising: correlation means for re-forming the data to have the same time length and calculating the correlation. 2. The information transmission device according to claim 1, wherein the information is constituted by fishing net detection information obtained by detecting the upper and lower parts from the opening of the fishing net, and the transmitted wave is formed by underwater ultrasonic waves. An information transmission device characterized by comprising: 3. The information transmission device according to claim 1, wherein the information distribution time lengths are formed to be different from each other, and the information distribution time lengths are re-formed to the same time length. 1. An information transmission device characterized by comprising means for differentiating a write time for storing the content into a memory and a read time for reading out the content stored in the memory.