SU1656331A1 - Acoustic distance meter - Google Patents

Abstract

This invention relates to a measurement technique and can be used for level measurement. The purpose of the invention is to improve the measurement accuracy and provide a digital representation of the measurement results. The synchronizer 1 starts the acoustic transceiving device 2 and the time separation circuit 3, and also initializes the pulse counter 6 and the pulse temporal position comparison unit 8. Acoustic transceiving device 2 emits acoustic pulses in the direction of reference reflectors 10. 11 and in the direction

Description

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object 14 and receives ultrasonic pulses reflected from them, which are then separated and appear at the outputs of the circuit 8 for time separation of signals. The trigger 4 is triggered by the pulse reflected from the reflector 10. and is tilted by the pulse reflected from the object 14. In this case, a generation occurs in the generator 5, and the time interval formed by the trigger 4 is filled with the pulses that are counted by the counter b and the number

The invention relates to a measurement technique and can be used to measure distances or levels by acoustic waves.

The purpose of the invention is to improve the measurement accuracy and obtain a digital information output.

Figure 1 shows a functional diagram of an acoustic distance meter; figure 2 - diagrams of signals characterizing his work; on fig.Z - scheme KUGI; 4 shows a fixed number decoder; Fig. 5 is a block diagram of the comparison of the temporal position of the pulses.

Acoustic distance meter contains synchronizer 1 connected in series. Acoustic receiver-emitting device 2, time separation circuit 3, the second input of which is connected to the synchronizer, trigger 4, which second input is connected to the measuring output of the time separation circuit 3, key controlled oscillator 5 pulses, a counter 6. the setup input to the initial state of which is connected to the synchronizer 1, a decoder 7 of a fixed number, a block 8 comparing the time position of the pulse c, the second comparing input of which is connected to the second reference output of the time-sharing circuit 3, and the setup input is connected to the synchronizer 1, and the low-pass filter 9, the output of which is connected to the control input of the key controlled oscillator 5 pulses and two reference reflector 10 and 11; Additionally, for indicating digital measurement information from the output of counter 6, the buffer 12 is sequentially connected to the latter, the transfer input of which is connected to the measurement output of circuit 3 signals and the indicator 13. The distance is measured to the reflector 14.

The acoustic distance meter works as follows.

which is equal to the measured distance. A chain of fixed-number decoder 7 connected in series, pulse timing comparison unit 8 and low-pass filter 9 controls the frequency of oscillator 5 in accordance with the speed of sound in the medium. This ensures that the level measurement results are independent of the speed of sound, accuracy is improved and digital output. 5 yl

The synchronizer 1 generates a pulse (FIG. 2a), which triggers the acoustic transceiving device 2 and the time separation circuit 3, as well as

sets the pulse counter 6 to its original state. The acoustic transducer 2 emits acoustic pulses in the direction of the reference reflectors 10 and 11 and in the direction of the object 14, the distance

how much is measured. Reflected from the reference reflector 10, the acoustic pulse is received by the acoustic transceiver 2 and through the circuit 3 for time separation of signals.

(Fig. 2b) sets the trigger 4 to the one state (Fig. 2e). KUGI 5 begins to generate pulses synchronous with the beginning of the pulse of trigger 4 (Fig. 2e) Reflected from the reference reflector 11, the acoustic pulse is received by the acoustic transceiver 2 and through the time separation circuit 3, the signals arrive at the second input of the time position comparison unit 8

pulses (figv). The first input of block 8 receives a pulse from the decoder 7 when the counter 6 counts the number of pulses that it decodes 1 the decoder 7 of a fixed number. If a pulse arrives at the first input of block 8 earlier (fig. 2e) than the pulse reflected from the reference reflector 11 (fig. 2c), then block 8 produces a negative pulse that lowers the voltage at the output of the low-pass filter 9 (fig .2i) This leads to a decrease in the frequency of the KUGI 5, and in the next period of sounding the temporal mismatch will decrease between the input pulses of block 8 As a result

after several periods of probing, a temporary coincidence is established between the pulses arriving at the input of the block 8 and the meter can later produce information about the measured distance not

depending on the speed of sound in the medium. If the momentum from the reference

the reflector 11 is ahead of the pulse arriving at the other input of the block 8 from the decoder 7, then the block 8 forms a positive pulse, which leads to an increase in voltage at the output of the filter 9 and to an increase in the frequency generated by the KUGI 5. Again, equilibrium occurs again. The voltage at the output of the low-pass filter 9 only changes during the error time of the input pulses of the pulse position comparison unit 8, which is in sync from the synchronizer to the working state every probe period (Fig. 2a). Reflecting from object 14. An acoustic pulse is received by an acoustic transceiver device 2 and through the circuit 3 for time separation of signals arrives at trigger 4 (Fig. 2d) and sets it to the zero state (Fig. 2e). The KUGI 5 stops the generation of pulses (Fig. 2e) and the counter 6 stops. The information at the output of the counter 6 is expressed in digital form and corresponds to the measured distance to the object 14. Buffer 12 and the indicator 13 are connected to the measurement information of the counter 6 and the information 13 is transferred from the counter b to the output of buffer 12 at the moment of receiving the pulse reflected from the object 14 (Fig 2rj

The peculiarity of the KUGI 5 scheme (FIG. 3} is that it (generates synchronous pulses with an input trigger pulse (FIG. 2d) This is necessary; this is to ensure the tracking error of a fixed number of pulses of the CUGI 5 t secondary reference pulse (Fig. 2c ) less than the period of the pulse of the CUGI 5. This is because all; yes, the phase relations of the generated 5 CUGI pulses with its triggering pulse are known (Fig. 2e)

The decoder 7 of a fixed number decrypts the number 50. if the output of counter 6 is a binary-decimal code. and both inputs are connected to the 5th and 7m / dispenser discharger, i.e. the output of this decoder appears to be a positive front then Cfd1, for example, in a three-way counter 6 and the position 0000 OU POOP

Comparison unit 8 (in addition, there are no impulses in front of each probe; about,, live is set r. G / one1

STATE OF PULSE (L CH l-tJf CHICH PG |,.

Then at the point between the slaughter i Smmi), the reading is approximately equal to glnc-ng-n.IT ;, which is used for the microcircuit n-tr, to the direction of the HL, transistor is closed. If le ;, the positive front comes to L1 then

a negative front is formed at the output of the upper trigger; as a result, the lower transistor opens. When comes

0 second positive front in B2. then the inverted output of the lower trigger acquires a state of 1st, and the lower transistor closes. After exposure to the sync pulse, the circuit is again ready for operation. If the first positive front comes in 8x2. then during the time of the input front mismatch, the upper transistor is open. Thus, the voltage at the output of the low-pass filter 9 is varied only during the time difference between the input positive fronts. This allows tracking of a fixed number of periods of the KUGI 5 with the signal reflected from the secondary reflector 11 with high accuracy.

The proposed acoustic distance meter has a high measurement accuracy, since there are no such sources.

0 errors, as nonlinearity of the integrator, controlled amplifier, instability of the reference voltage; increased noise immunity due to communication of block 8 with synchronizer 1, since this makes it possible, after exposure to strong impulse noise on one of the inputs of block 8, to set the circuit to normal operating mode in the next sensing period, increased measurement accuracy from the primary reference reflector 10. as distortion of the signal between the inter-unit / block 2 and the 10 HP reflector have a strong influence on the measurement accuracy; the ability to synchronize with an external device,

5 since the synchronizer does not need reverse synchronization for the synchronizer, and the information about the measured distance is obtained in a digital form and does not depend on the speed of sound propagation in the medium.

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Claims (1)

Claims of the invention Acoustic distance meter comprising a synchronizer connected in series, an acoustic transducer 5 emitting device and a time separation circuit connected to the synchronizer, two reference reflectors and a trigger, and the second inputs are connected to the first reference and measurement out-put of the time-phase circuit. de / t signals, characterized in that, in order to increase accuracy and obtain a DIGITAL you / ode, the meter is equipped with 11g; 5 control with a pulse generator, whose input is connected to the trigger output. a counter whose setup input is connected to a synchronizer, a fixed number decoder, a pulse position comparison unit, the second input of which is connected to the second reference output of the circuit, times signal separation, and the setup input is connected to a synchronizer and a low-pass filter, the output of which is connected to the control input of a key controlled pulse generator. Maud e KO FIG H