JPH0370796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that measures distance by transmitting and receiving pulsed signals and is capable of recording a large number of received signals.

A conventional distance measuring device of this type is shown in FIG. 1, and its operation timing chart is shown in FIG. In FIG. 1, 1 is a timing pulse generation circuit, 2 is a pulse modulation oscillation circuit, 3 is a power amplifier, 4 is a transmission/reception switch, 5 is an ultrasonic transmitter/receiver, 6 is an amplifier,
7 is a detection circuit, 8 is a flip-flop, 9, 1
2, 13, 14, 15 are AND gates, 10 is a clock oscillator, 11 is a counting circuit, 16 is a memory, 17 is an arithmetic control circuit, 18 is a display circuit, 19
is underwater, and 20 is the bottom of the water (object to be measured).

In the above configuration, the transmission timing pulse a generated by the timing pulse generation circuit 1 is sent to the pulse modulation oscillator 2 and the set terminal of the flip-flop 8. The pulse modulation oscillation circuit 2 generates a pulse modulation signal b corresponding to the time width of the transmission timing pulse a. The signal b is amplified by the power amplifier 3, and further sent to the transmitter/receiver 5 via the transmitter/receiver switch 4, where it is converted into an ultrasonic signal S and transmitted in the direction of the water bottom 20. The ultrasonic signal S propagates through the water 19, reaches the bottom 20, is reflected there, is received again by the transmitter/receiver 5, and is converted into an electrical signal. The received (electrical) signal c passes through an amplifier 6 and a detection circuit 7, and if necessary passes through a waveform shaping circuit to become a reception timing pulse d and is sent to a reset terminal of a flip-flop 8. (Although a part of the pulse modulation signal b may leak through the transmitter/receiver switch 4, the width of the transmit timing pulse a supplied to the set terminal of the flip-flop 8 should be made longer by using a one-shot multi, etc. ) The flip-flop 8 is set and reset by the rising edge of the transmission timing pulse a and the reception timing pulse d, and its Q output contains the time between both pulses a and d, that is, the ultrasonic wave. A gate signal e corresponding to the time required for the signal S to travel back and forth (propagation) between the transmitter/receiver 5 and the bottom 20 is generated, and is sent to one input terminal of the AND gate 9.
A clock pulse f of a predetermined frequency is supplied from a clock oscillator 10 to the other input terminal of the AND gate 9, and a counting pulse g corresponding to the time width of the gate signal e is obtained at the output of the AND gate 9. The counting pulse g is counted by the counting circuit 11, and if the oscillation frequency of the clock oscillator 10 is set so that the distance L between the transmitter/receiver 5 and the water bottom 20 can be directly read, the counting can be performed. circuit 11
The count value becomes the distance L as it is.

The arithmetic control circuit 17 includes AND gates 12, 13,
14 and 15 at a predetermined timing to open each AND gate, and the counting circuit 11
The count value (in this case, a 4-bit binary number) is taken into the memory 16. Thereafter, the counted value is subjected to appropriate arithmetic processing and displayed on the display circuit 18.

In the above device, after the transmission timing pulse is generated and the ultrasonic signal S is transmitted from the transmitter/receiver 5, the flip-flop 8 is reset by the first received signal, and the counting circuit 11 is stopped. Therefore, if a floating object such as a school of fish exists between the transmitter/receiver 5 and the water bottom 20, or if underwater noise occurs, the signal reflected by the floating object or There was a risk that the flip-flop 8 would be reset upon receiving underwater noise, and the counting circuit 11 would stop, resulting in erroneous measurements.

Furthermore, since the counting circuit 11 normally outputs the numerical value of each digit in parallel from separate signal lines, it requires as many AND gates (four in this case) to exchange signals with the memory 16. year,
The disadvantage was that the circuit configuration was complicated.

In order to eliminate the above-mentioned conventional drawbacks, the present invention sequentially stores the signals received by the transmitter/receiver in a shift register that is shifted by a shift pulse of a predetermined frequency, reads out the recorded contents of the shift register serially, and All received signals, such as signals reflected from floating objects, underwater noise, and signals reflected from the bottom of the water, are recorded with information about their reception time differences by sending them to memory as signals representing bit differences between signals. Accordingly, distance information to a plurality of objects to be measured can be obtained, and the device configuration is simplified.The drawings will be described in detail below.

FIG. 3 shows an embodiment of the distance measuring device of the present invention, in which the same components as in FIG. 1 are denoted by the same reference numerals. That is, 1 is a timing pulse generation circuit, 2 is a pulse modulation oscillation circuit, 3 is a power amplifier, 4 is a transmitter/receiver switch, 5 is an ultrasonic transmitter/receiver,
6 is an amplifier, 7 is a detection circuit, 16 is a memory, 17
is an arithmetic control circuit, 18 is a display circuit, 19 is underwater,
20 is the bottom, 21 is a 16-bit shift register,
22 is a shift pulse generation circuit, 23 and 24 are AND gates, 25 is an OR gate, and 26 is a floating object such as a school of fish. Figure 4 A to E show the shift register 21
In the figure, the shaded area indicates "1" information, and the other sections indicate "0" information.

Next, the operation will be explained. The transmission timing pulse generated by the timing pulse generation circuit 1 is sent to the pulse modulation oscillation circuit 2 and also to the arithmetic control circuit 17. The pulse modulation oscillator circuit 2 receives the transmission timing pulse and generates a pulse modulation signal, and the pulse modulation signal is sent to the transmitter/receiver 5 via the power amplifier 3 and the transmitter/receiver switch 4, where it is converted into an ultrasonic signal. Converted to S and underwater 20
is sent in the direction of

On the other hand, when the arithmetic control circuit 17 receives the transmission timing pulse, it opens the AND gate 24 and supplies the shift pulse of a predetermined frequency generated by the shift pulse generation circuit 22 to the shift register 21 through the AND gate 24 and the OR gate 25. Note that in the initial state, the shift register 21
Assume that the contents of are all "0" as shown in FIG. 4A.

A part of the pulse modulation signal sent from the power amplifier 3 to the transmitter/receiver switch 4 leaks to the amplifier 6,
The signal is amplified and further passed through the detection circuit 7 and added to the shift register 21 to which the shift pulse has begun to be supplied, and is stored as a signal 31 indicating the transmission timing at the 0th bit as shown in FIG. 4B. after that,
The contents of the shift register 21 are shifted by shift pulses.

The ultrasonic signal S propagating through the water 19 is
If there is a floating object 26 between the receiver 5 and the water bottom 20, a part of it will be reflected by the floating object 26 and will not be transmitted or transmitted.
It is received by the receiver 5. The reflected signal from the floating object 26 is stored in the 0th bit of the shift register 21 via the transmission/reception switch 4, the amplifier 6, and the detection circuit 7. FIG. 4C shows the state at this time, in which the ultrasonic signal S is transmitted and the floating object 26 is
Seven shift pulses are generated until the reflected signal 32 is received, and the signal indicating the transmission timing has been shifted to the 7th bit. Further, when the ultrasonic signal S reflected from the water bottom 20 is received by the transmitter/receiver 5, it is stored in the 0th bit of the shift register 21 as described above. FIG. 4D shows the state at this time, in which four shift pulses are generated from the time the reflected signal 32 from the floating object 26 is received until the reflected signal 33 from the water bottom 20 is received. . The shift pulses sent to the shift register 21 are also sent to the arithmetic control circuit 17, and when the arithmetic control circuit 17 counts the shift pulses by the number of bits in the shift register 21, that is, 16, it closes the AND gate 24 and starts shifting. stop. FIG. 4E shows the state at this time, and the signal 31 indicating the transmission timing is stored in the last 15th bit. Here, the difference in the number of bits between the recording areas of each signal 31, 32, 33 in the shift register 21 represents the reception time difference between each signal.

Next, the arithmetic control circuit 17 opens the AND gate 23, sends a shift pulse to the shift register 21 at a predetermined timing through the OR gate 25, and stores the contents of the shift register 21 in the memory 16 in the manner described below. That is, first, one shift pulse is sent to the output terminal of the shift register 21, that is,
Incorporates the contents of the 15th bit and simultaneously stores memory 16.
The contents of address N (in the initial state, memory 16
The contents of each address are all set to "0"), and "1" is added to them. If the taken-in data is "0", one more shift pulse is sent to the shift register 21, and "1" is further added to the N address of the memory 16.
Repeat this until the imported data becomes "1". If the imported data is “1”, the contents of the N address are left as is and the shift pulse is further set to 1.
At the same time, "1" is added to the contents of address (N+1). Below, as mentioned above, when data "0" is obtained, "1" is added to the address at that time, and when data "1" is obtained, the address is updated, and the total number of shift pulses is 16. This is repeated until all the contents of the shift register 21 are taken in.

When the contents of the shift register 21 shown in FIG.
+2) The content of the address is "4". That is, the transmitted signal 31, the reflected signal 32 from the floating object 26, and the bottom 2
The difference in the number of bits in the shift register 21 for each signal such as the reflected signal 33 from 0 is stored at each address in the memory 16.

The propagation speed of sound waves in water 19 is C (m/
sec), and the time it takes for the transmitted sound wave to be received again is T (sec), then the distance L between the transmitter/receiver and the object to be measured is: L=1/2・C・T becomes. Here, C is almost constant regardless of the water depth, and as mentioned above, the bit difference between each signal in the shift register 21 represents the reception time, so the shift is made so that 1 bit in the shift register 21 becomes the unit depth. If the oscillation frequency of the pulse generation circuit 22 is selected, L=1/2・C・T=M. M is the number of shift pulses occurring within time T. Therefore, floating objects 26 are removed from the transmitter/receiver 5.
The depth L ₁ from the transmitter/receiver 5 to the bottom 20 is L ₁ = M ₁ ...(1)
L ₂ becomes L ₂ =M ₁ +M ₂ (2). Here, M ₁ and M ₂ indicate the contents of the (N+1) address and (N+2) address of the memory 16, respectively.

The above information is transferred from the memory 16 by the arithmetic control circuit 17.
M ₁ and M ₂ are read, and the arithmetic processing of equations (1) and (2) above is performed and displayed on the display circuit 18.

As described above, according to the above embodiment, since the received signal is stored in the shift register 21 to which a shift pulse of a frequency corresponding to the unit depth is added, the floating object 2 is a reflector for a plurality of sound waves.
6. Depth information such as the underwater bottom 20 can be recorded. Furthermore, the contents of the shift register 21 are serially input to the arithmetic control circuit 17 through the AND gate 23, and the number of bits between each received signal, that is, the depth, is stored at each address of the memory 16, so that the conventional counting circuit It is not necessary to provide an AND gate corresponding to each digit signal as is the case when using a 2-digit signal, the device configuration is simpler, and the depth to the object to be measured can be easily determined by adding up the contents of each address in the memory It can be calculated as follows.

Note that the determination as to whether the depth stored at each address in the memory 16 is of the floating object 26 in the water 19 or the water bottom 20 is based on the water bottom 2 before and after the depth.
This can be determined by calculating the correlation with the depth of 0 using the arithmetic control circuit 17.

Although the memory 16 is configured as 16 bits in the above embodiment, it can actually have any number of bits. Further, although the transmitter/receiver 5 and the transmitter/receiver switch 4 are used to transmit and receive ultrasonic signals, the transmitter and receiver may be configured separately. Furthermore, in the above embodiment, the case of measuring the depth of water was described, but it can also be applied to measuring the distance to buildings, etc. in the atmosphere. Further, the shift pulse directly supplied from the arithmetic control circuit 17 to the shift register 21 can be set independently of the oscillation frequency of the shift pulse generation circuit 22, and the reading speed can be increased by lowering the frequency.

As explained above, according to the present invention, a distance measuring device that measures the distance to an object by transmitting and receiving pulsed signals includes a shift register that sequentially stores the received pulsed signals, and a shift register that sequentially stores the received pulsed signals. a shift pulse generating means for generating shift pulses; a memory having a plurality of addresses; supplying a predetermined number of the shift pulses to the shift register from the time of transmission of the pulse-like signal, and serially transmitting data from the shift register; Since it is equipped with a control means for reading and storing the bit difference between each pulse-like signal of the data string in each address of the memory, it is necessary to read only the first received signal for one transmitted signal as in the conventional method. It is possible to record a plurality of received signals with information regarding the difference in reception time, and therefore, it is possible to reliably measure distance information to a plurality of objects to be measured including the target object to be measured. Unlike the case where a conventional counting circuit is used, a large number of gate circuits are not required to store the reception time, and the device configuration becomes simpler.

Further, according to the present invention, in a distance measuring device that measures the distance to an object to be measured by transmitting and receiving pulsed signals, there is provided a shift register that successively stores the received pulsed signals, and a shift register that sequentially stores the received pulsed signals. a shift pulse generating means for generating a shift pulse, a memory having a plurality of addresses, and supplying a predetermined number of the shift pulses to the shift register from the time of transmission of the pulse-like signal, and reading data serially from the shift register; Since it is equipped with a control means that stores the bit difference between each pulse-like signal of the data string at each address of the memory and further calculates the sum of the stored contents at each address, it is possible to measure the distance to the target object to be measured. Information can be obtained immediately and can be used for echo sounders, water level gauges, etc.

[Brief explanation of drawings]

The drawings serve to explain the present invention. FIG. 1 is a block diagram showing an example of a conventional distance measuring device, FIG. 2 is an operation timing chart of each part of the device shown in FIG. 1, and FIG. A block diagram showing one embodiment of the distance measuring device, and FIGS. 4A to 4E are explanatory diagrams showing the storage state of the shift register. 1... Timing pulse generation circuit, 2... Pulse modulation oscillation circuit, 4... Transmission/reception switching device, 5... Transmission/reception switch.
Receiver, 7...Detection circuit, 16...Memory, 17
... Arithmetic control circuit, 18 ... Display circuit, 19 ...
Underwater, 20...bottom, 21...shift register,
22...Shift pulse generation circuit, 23, 24...
And gate, 25...or gate, 26...floating object.

Claims (1)

[Claims] 1. A distance measuring device that measures the distance to an object by transmitting and receiving pulsed signals, comprising: a shift register that sequentially stores the received pulsed signals; and a shift register that generates a shift pulse of a predetermined frequency. a memory having a plurality of addresses; supplying a predetermined number of the shift pulses to the shift register from the time of transmission of the pulse-like signal, reading data serially from the shift register; A distance measuring device comprising: control means for storing the bit difference between each pulse-like signal of the column at each address of the memory. 2. A distance measuring device that measures the distance to an object by transmitting and receiving pulsed signals, comprising: a shift register that sequentially stores the received pulsed signals; and a shift pulse generation means that generates a shift pulse of a predetermined frequency. , a memory having a plurality of addresses, and supplying a predetermined number of the shift pulses to the shift register from the time of transmission of the pulse-like signal, reading data serially from the shift register, and reading each pulse-like signal of the data string. A distance measuring device comprising: a control means for storing the bit difference between the two addresses in each address of the memory, and further calculating a sum of the contents stored at each address.