SU1610308A1 - Meter of sound speed - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the speed of sound in liquid media. The purpose of the invention is to improve the measurement accuracy by eliminating the time zone of insensitivity of the operation of the divider. The measurements use the signals reflected from the boundary of the protector of the electroacoustic converter — the medium under study and propagating in the protector, as an element of memory that stores the duration of time intervals, is used by an integrator, and a comparator is used to compare time intervals converted to voltages. 2 Il.

Description

The invention relates to a measurement technique and can be used to measure the speed of sound propagation in liquid media.

The purpose of the invention is to improve the measurement accuracy by reducing the parasitic delay time.

FIG. 1 shows a structural diagram of the proposed meter; in fig. 2 - time diagrams that show his work.

The meter contains a series-connected pulse generator 1, an electro-acoustic converter 2 (EAF) with protector 3 and a reflector 4, a pulse limiter 5 and a first comparator 6, a control key 7 connected in series, an integrator 8 and a second comparator 9, series-connected control generator 10, a frequency divider 11 and a pulse distributor 12, two circuits, each of which consists of a series-connected controlled RS trigger 13 (14), an integrator 15 (16), and

adder 17 (18), the recorder 19, whose input is connected to the output of the controlled generator 10, RS-flip-flop 20, counting flip-flop 21, delay line 22 and the OR circuit 23. The first output of the pulse distributor 12 is connected to the inputs of the pulse generator 1 and the line 22 delay, the second output of the distributor 12 pulses is connected to the first input of the OR circuit 23 and to the S input of the counting trigger 21, the third output of the distributor 12 of pulses is connected to the R input of the counting trigger 21 and to the control input of the first RS controlled trigger 13, fourth outlet of the distributor 12 imp pulses are connected to the second input of the OR circuit 23. The fifth output of the pulse distributor 12 is connected to the control input of a controlled RS flip-flop 14 of the second circuit. The second input of the first co-driver 6 is connected to the output of the delay line 22, the output of the first comparator 6 is connected to the C input of the counting trigger 21, the control input of the control key 7 is connected to the output of the counting trigger 21, information

with

oh oh

SA)

R

00

 The control input of the controlled key 7 is grounded, the second input of the second comparator 9 is connected to the output of the second circuit tumbler 18, the input of the controlled generator 10 is connected to the output of the adder 17 of the first circuit, the direct and inverse outputs of P5-T0igger 20 are connected respectively to S- and R - the inputs of the controlled RS-flip-flops 13 and 14 of the first and second circuits, the second inputs of the adders 17 and 18 of the first and second circuits are intended for connection to positive voltage sources, the S and R inputs of the RS flip-flop 20 are connected respectively to the outputs of the second comparator 9 and OR schemes 23.

The meter works as follows.

Pulses with frequency F of controlled generator 10 through frequency divider 11 with division factor K are fed to the input of distributor 12 pulses. The pulses at the outputs of the distributor 12 are shown in diagrams 24-31 (Fig. 2).

On the leading edge of the pulse 24 from the first output of the distributor 12, the generator 1 by the pulse 32 excites the EAP 2 emitting acoustic oscillations. After propagation in protector 3, acoustic oscillations partially pass into the controlled medium, and partially reflect from the protector 3 boundary — the medium due to the difference in their acoustic impedances and return back along the thickness of protector 3 to the EAP 2 through time Hn and convert to the first received signal A .

Acoustic oscillations, propagating in a controlled environment, reach the reflector 4 and, reflected from it, return back after a time of 2 Tx to the EAP 2, where they are converted to the second receiving signal B.

The first comparator 6, gated at the second input through the delay line 22 from the leading edge of the pulse 24 of the first output of the distributor 12, does not pass the shock excitation pulse A into the measuring channel. The pulses C and D from the output of the comparator 6 arrive at the C input of the counting flip-flop 21, forming a pulse 35 at its input, controlling through the switch 7 the charge of the capacitor of the integrator 8.

Linearly increasing voltage 36 of integrator 8 is fed to the input of the second comparator 9, where it is compared with the reference voltage at the second input of the comparator 9. When the voltages are equal at the inputs of the output of the comparator 9, a pulse 37 occurs, setting the RS flip-flop 20 to state 1 ( diagram 38 in Fig. 2).

A controlled RS flip-flop 14 for a pulse duration of 26 from the third output of the distributor 12 acting on its control V input is set to

also in state 1, allowing the charge of the capacitor of the integrator 16. The voltage 39 at the output of the latter increases to a certain value, which is summed at the input of the adder 18 with the voltage Uo,

increases at its output up to the value of U d (chart 39 in Fig. 2) entering the reference input of the comparator 9.

Thus, the voltage is proportional to the informative length of 2 Gx

(Diagram 34 in FIG. 2). The set of blocks 21, 7, 8, 9, 20, 14, 16 and 18 is the next converter, the duration of the time interval 2 Gks - voltage, the output voltage of which is not

depends on the random effects of external conditions, interference and leakage of a capacitor. The voltage Uo at the input of the adder 18 differs from the maximum value of the voltage at the input of the integrator 8 by an amount determined by the effects of temperature, interference and instabilities of the elements.

The impulse from the fourth output of the distributor 12, entering the S-in. RS-flip-flop

20, sets it again to state 1 (FIG. 40 in FIG. 2). Through a controllable switch 7, the capacitor of the integrator 8 begins to charge, transforming into a voltage of duration 2 Three two consecutive (fourth and fifth) output pulses of the distributor 12. When the linearly varying voltage reaches, the value equal to Ui (diagram 41 in Fig. 2 ) on the reference input of the comparator 9, on

the output of the latter is formed by the output pulse 42 (Fig. 2), as a result of which RSr trigger 20 is set to state 1, and during the sixth pulse of the distributor 12 acting on the control

The V-input of the controlled RS-flip-flop 13, from the output of the latter, the logical 1 signal is fed to the input of the integrator 15, providing the charge of its capacitor, the voltage of which is shown in diagram 44 (Fig. 2).

The output voltage of the adder 17, which is the sum of the voltage (diagram 44 in Fig. 2) of the integrator 15 and the constant voltage, is fed to the input

controlled oscillator 10. At the same time, its frequency increases, and the duration of the pulses of the distributor 12 decreases. Reducing the duration of 2 Gris leads to the convergence of the leading fronts of the output

pulse (diagram 42 in FIG. 2) of the comparator 9 and pulse (diagram 29 in FIG. 2) from the third output of the distributor 12.

The adder 17 serves to accelerate the achievement of a steady state upon power up. If the output frequency of the meter, proportional to the change in the speed of sound from Cmin to Stax, changes from Fmin to Fmax, then the voltage value + Uo is selected from the condition that the frequency Fmin is applied at the output of the controlled oscillator 10 when it is influenced by its voltage control input.

In the steady-state mode of operation, the meter is in compliance with the condition 2Gx 2Gy,. -2L., K

kcQ-, and Three p-, THEN

Ks l as well as

F

Claims (1)

Invention Formula A sound speed meter containing a series-connected pulse-generator, an electro-acoustic transducer with a reflector, a pulse stop and the first comparator, a successively connected controlled oscillator, a frequency divider and a pulse distributor, the first output of which is connected to the input of the pulse generator, and a recorder whose input is connected to the output of the controlled oscillator, characterized in that, in order to improve the measurement accuracy, it is equipped with two objectives, each of which consists of e10 0 5 0 5 a connected RS trigger, an integrator and an adder, a second comparator, an RS trigger, a counting trigger, a delay line whose input is connected to the first output of the pulse distributor, the output of the delay line and the OR, S- circuit and the R-inputs of the controlled RS-flip-flops are connected respectively to the direct and inverse outputs of the RS-flip-flop, the C-input of the counting trigger is connected to the output of the first comparator, the second output of the pulse distributor is connected to the first input of the OR circuit and the S-in the counting trigger's one, the third output of the IM-pulses distributor is connected to the R-input of the counting trigger and the control input of the controlled RS-flip-flop of the first circuit, the output of the counting trigger is connected to the control input of the control key, the information input of which is grounded, the integrator's output is connected with the first input of the second comparator, the second input of which is connected to the output of the adder of the second circuit, the output of the second comparator is connected to the S input of the RS flip-flop, the second input of the OR circuit is connected to the fourth output of the pulse distributor, the fifth output of which is connected to the control input of the controlled RS-flip-flop of the second circuit, the output of the OR circuit is connected to the R-input of the RS-flip-flop, the second inputs of the adders of the first and second circuits are connected to positive voltage sources, and the output of the first circuit adders connected to the input of the controlled generator. - „-