JPS6098375A - Multiple echo signal eliminating device - Google Patents

Abstract

PURPOSE:To make a displayed record easy to see and to improve the read precision by eliminating a multiple echo signal from a received signal in accordance with variance of the water depth. CONSTITUTION:The received signal inputted from a sensor system 1000 is supplied to an A/D converter 1, an LPF6, a level detecting circuit 7, an analog gate circuit 12, etc. The received signal digitized by the A/D converter 1 is supplied to a memory 2. The received signal supplied to the memory 2 is written under the control of a system controller 3 by a write/read controller 4 and an address controller 5 and is read in time division by a clock signal which is set in accordance with the number of multiple echo signals which should be eliminated from the received signal. Received signal data read out from the memory 2 is given to the analog gate circuit 12 through a D/A converter 9, and LPF10, and a level detecting circuit 11. A desired received echol is led out from this gate circuit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiplicity t# signal removal device, and a special K tNI
The multiplex signal contained in the received signal is obtained when obtaining depth sounding or exploration records of the ocean floor etc. by emitting a transmission pulse t-i of a sound wave etc. almost vertically downward and receiving all the echoes, such as with a J-deep plane. The present invention relates to a multiple echo signal removal device whose entire purpose is to eliminate echo signals.

A sounder can emit sound waves all over the ocean floor simultaneously to obtain echoes as information on water depth, or as a type of geophysical exploration, various types of vibrational energy such as air guns and sparkers can be used to capture the ocean floor and seafloor. Even when acquiring echoes as the yellow structure information of F, the acquired echoes often include multiple echo signals.This multiplicity 4 signal is, for example, due to the 1g multiplication signal in the case of a sounding machine. This is caused by the echoes traveling back and forth between the transducer and the seabed until the attenuation is below the recorded detection level.If we take all the correct DL11 depth data from the Senbokujo-go, it is 2 JJ.
, 3J).

4D..., etc., the signal is recorded or displayed as a plurality of multiple echo signals until it becomes below the Mα recording detection level at an integer multiple of the depth.

Such multiple echo signals occur at the Leprosy Signal No. 1B level, and therefore in shallow waters where the attenuation relative to the echo level is small. Depending on conditions such as the transmitting signal level, receiving gain depth, seabed quality, etc. It is not uncommon for new sounding data to be displayed one after another, and this itself is basically due to problems such as difficulty in reading sounding records and exploration records, and promoting the reliance on digitized data. Since this problem often occurs, we always try to eliminate it as follows.

In other words, this type of conventional multiplexing! The 1111 multiplier removal device has a transmitting output level and receiving gain control circuit for applications where the generation of multiple echo signals is inevitable, such as in sounding machines or the above-mentioned geophysical survey equipment. The most expensive method is to suppress and eliminate multiple echo signals by manually controlling one or both of these control circuits in response to water depth data while monitoring all recordings.However, this method is expensive. As mentioned above, conventional multiple echo signal removal devices rely on manual control of the transmission output level, reception gain, or both, which inevitably results in uneven removal effects, making it difficult to see echo records. Moreover, when echo records are digitized, there are various drawbacks such as the reliability of the data to be quantized goes down by one level and the probability of correct detection tends to drop significantly.

The object of the invention is to eliminate the above-mentioned drawbacks and to make the records extremely easy to read by providing means for automatically removing all multiple echo signals while responding to changes in the position of the echo bar due to sounding (logging, etc.), that is, changes in water depth. To provide a multiplex anti-quad code removal device which greatly improves the overall reading accuracy and significantly improves the data indentation accuracy during digitization. It is in.

The device of the present invention is capable of detecting hl using a sensor ν such as a depth sounder.

In a multiple echo signal removing device that removes multiple anti-quadruple signals contained in the received 1d Gogo, the received signal is digitized, all of which is written in a memory with a clock signal of a preset frequency f, and is targeted for removal. A frequency sequence (-・f) (
net prime number 2.3.5...) () black, ri1 @
Time-division read data depending on issue? and a time gate signal generating means for generating all the time gates 16 corresponding to the timing and time width of the time-division read data and suppressing the output of the multiple inverse signals.

? :i,,VC The present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

One implementation of the non-invention shown in Figure 1 llv: J,, A/D
Converter 1. Memory 2. System controller 3゜Writing edge controller 4. Address controller 5.
LPF (Low Pa5s Filter) 6.
L/bevel output circuit 7. Counter circuit 8. JJ/A converter9. In addition to LPFIO, level detection circuit 11 and analog gate circuit 12, sounding? A sensor system 1000 such as 3J is also shown.

Sensor system 1000. In the case of non-embodiment, the input line 101 is connected to the sensor system 1000 that uses a sounding machine.
'The received signal input manually through A/L) converter 1
．． LPF6. Level detection circuit 7. Analog gate circuit 1
It will be supplied to each of the two temples.

A/1) The converter l digitizes the analog received signal with a preset number of bits and supplies it to the memory 2. The digital routers supplied to the memory 2 are operated by a write/read controller 4. under the control of the system control operations of the system controller 3. Under write control and address designation by the address controller 5, the number of multiple echo signals to be removed from the received signal is written to the scale 2 with a clock number 4g of frequency f, up to the fourth echo in non-embodiments. The readout controller 4 performs all the time-division readout using clock signals of two frequency series corresponding to the number of three unpleasant multiple echo signals, and supplies this to the output line 201 to the 1)/A converter 9.
Execute time-division readout that performs readout control and address specification in this readout.
The frequency of No. 6 is the frequency fVc of the writing black and qui-no.
On the other hand, -・fCn is a prime number 2.3.5...)1・f
, -・f... are used in accordance with the number of multiple echoes to be removed (N5).For example, readout of nest 2 echoes and readout of -f are performed in a time-sharing manner. Furthermore, the data read out at the lock frequency can be used to remove multiple echo signals contained in the original receiving signal, as described later. The signal is not only the second echo but also the fourth, sixth, and so on.
2m such as the 8th echo (m2 1.2, 3.4...
...) can be used to remove the @th echo, and -f can be used not only to remove the 3rd echo but also to remove the 3m#th echo. What echoes should be removed?

Usually, the 5th or 6th echo is the limit,
Therefore, the frequency series of the clock signal during time-division readout can be considered to be approximately limited to 2 3 5 time-division readout by -·f, -·f, and -·f. It is also clear that n, which determines the frequency -°f of the black and red signals, is a prime number of 2.3.5.

FIG. 2 is a waveform diagram of received echoes (Al and time-division read data (L) and multiple echo signal removed receiving echoes (B) in the embodiment of FIG. 1.

The embodiment shown in FIG. 1 will be described below with reference to FIG.

In FIG. 1, the write controller 4 executes a write command and a read command for the echo pulse of the received signal to be written and stored in the memory 2 at a clock frequency f, then f, under the control of the system controller 3. However, in this case, the write timing, read timing, and number of time-division readouts are determined by the output line 801 Kl from the counter circuit 8 and the system controller 3.
The received echo information data sent to the receiver is prefixed with l:.

Figure 2 (A) shows the received echo with the time axis at the top” 1 #
``* *E3 and E4 This is a received signal that includes k1 Normally, these echoes are further superimposed with various noises including reverberation before being received. Among these echoes, El is a received signal containing 1M.
No.P. e is the desired echo obtained after a time T corresponding to the water depth, E, , E3. E4 is time T
The second one occurs separately. Third. This is the fourth multiple echo signal. The level of these echoes decreases in accordance with the number of reciprocations, and the echoes disappear. -Such echoes E, ~E4 are output by the sensor system 1000 along with noise, but the noise output together with the echoes E1~E4 Of these, noise in the high-frequency mantissa component that is higher than the frequency component corresponding to the echo envelope is usually removed by the sensor system 1000, so that the received signal supplied to the LPFry and level detection circuit 7 is equal to the tl of the echoes E, ~E4. , contains only noise components of low frequency components below the frequency components corresponding to the envelopes of these echoes.

LPF6 is a preset cutoff frequency 't'F that is lower than the lowest frequency component of the envelope of echoes E1 to E4.
This is a low-pass filter with a characteristic similar to that of R, and the echo component of the receiver 1g1g supplied to this LPF 6 is cut out, and only the low frequency noise component below the low envelope frequency is constantly filtered out. The signal is output at a level that changes with time and is supplied to the level detection circuit 7.

The level detection circuit 7 performs all level comparisons between the noise component outputted in this way and the reception signal 41, and uses the noise component that changes over time as a decision threshold value.

The echo pulse is sent to all counter circuits 8 by adding the manually generated value exceeding the level set by Kaneko with the echo.

The counter circuit 8 generates a number of pulses -th corresponding to the manually generated echo, and outputs this as received echo information to an output line 80.
1 to the system controller 3, and the write/read controller 4. and the necessity of the address controller 25 in this write/read control (provided as #*).The received number 1 data read out from the memory 2 in this way is supplied to the /A converter 9 via the output line 201'. and converted to analog data.

FIGS. 2B and 2(1) show the time-division read data thus obtained, and FIG.

Figure 2 (one) is written and stored at frequency f Figure 2 +
The transmitted signal and received echo shown in A) are read by 'if/2, and the transmitted signal Po has twice the time width P.
O2 and echo 1' 1 * El are read out as averages / , E, / with twice the time width, respectively. Furthermore, as shown in Fig. 2(C), what is read out using the clock signal of -f is that the transmitter No. 100 Po has three times the time width P, and the echo E1 also has three times the time width. E
3'.

Now, the read data E1' of FIG. 2(B) is read out.
The time gate signals 01 and Of that correspond to the generation timing and time width of are generated, and as a result, as shown in FIG.
Human echo series shown in N"'1 @ El eE3.
If a processing removal gate is applied during reception processing of E4, etc., echoes E2, E4, etc., which are multiple echo signals, will be successively removed from the opposite wall of the reception processing.

Similarly, the echo E3 is removed from the reception process by the time gate 1g Gs generated based on the read data in FIG. 2(C). Transmission 1H No. POrPo' and P, // are necessary for setting the echo manual timing, etc., but depending on the 1 time division escape and the setting of frequency - f, the desired 1st echo EI and the time during reception processing may be Since there is a possibility that the signal may be overloaded, the time width of the transmission No. 1g in the time-division read data is set in consideration of this point.

The results of removing all multiple echo signals in this way are shown in Figure 2 (
As in the case of kalpa, it is possible to automatically obtain data based on the received signal based on only the desired echo E1 and the transmitted signal P, which is easy to obtain (h) 1, and can significantly improve the reception processing accuracy. The embodiment shown in FIG. 1 is also designed to remove multiple echo signals from the received signal from this viewpoint.

Now, all of the time-division read data read out from the D/A converter 9Fi memory 2 in FIG. 1) is supplied as analog data to the PFIO and also to the level detection circuit 11.

1. PFIO is a frequency f slightly lower than the lowest frequency indicated by the envelope of the desired echo or multiple reflection 1 signal included in the data obtained through time-division readout.
, is an LPF with a cutoff frequency, which cuts high frequencies by using the echo or multiple reflection signal Kanakura described above, and supplies only the output of low frequency components below the cutoff frequency among noise components included in human power to the total level detection circuit 11. .

When the level detection circuit 11 detects the time-division read data output from the LPFIO output total detection band value, it supplies it to all these analog gate circuits 12, and based on this, the time division read data output from the A converter 9 is supplied to all the analog gate circuits 12. gate signal G,
, G, , G, etc. are generated.

All the received 1G double signals inputted manually through the input line 101 are gated and removed by the time gate IBA, and only the data regarding the desired received 1G echo and transmitted 1H signal are processed by the reception processing circuit, as shown in FIG. Send to record display circuit disease.

Level detection circuit lII/'i also. Information on the overlap between the above-mentioned transmission signal and Ml echo in the time-division readout data detected by level counting All output lines 1
The signal is sent to the system controller 3 via the system controller 3, and the entire time width of the transmission signal to be read is controlled under the control of the system controller 3.

In this way, only the desired received data can be fully received and processed while automatically removing multiple electromagnetic reflection signals.

Note that in this embodiment, time-division reading uses -.f and -.f;
It is clear that it would be possible to implement the same method even if ・) were used in combination with Renhui.

As explained above, according to the invention, the vertical position of a sounding device, etc. is automatically removed from all received multiple echo signals in response to changes in the position of the received signal obtained by the direction sensor, that is, the water depth. By equipping ourselves with means that can do this and making every effort to operate sensor systems such as sounding machines, we have made it possible to make the entire display record clear and easy to read, greatly improving the reading accuracy. This has the effect of greatly improving the probability of malfunction and making it possible to realize a multiple echo signal removal device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 shows received echoes (N and time-division read data tBl, (C) and multiplexed echo f4 in the embodiment of FIG. 1).
Signal cancellation reception echo (resistance).

Claims (1)

[Claims] In a multiple echo signal removing device that removes multiple echo signals contained in a received signal obtained by a sensor Vr of a sounding machine, etc., the received signal is completely digitized and is mesmerized using a clock signal of a preset frequency f. A frequency sequence (-・f) (n is a prime number 2.3.5...
...) for obtaining time-division read data using a clock signal, and generates a time gate signal corresponding to the timing and time width of the time-division read data to multiplex the previous n pins and # signal. and a time gate signal generating means for completely suppressing the output of a multiple echo signal.