CN206583498U - A kind of quick measuring circuit of ultrasonic transducer signal - Google Patents

Abstract

The utility model discloses a kind of quick measuring circuit of ultrasonic transducer signal, the test for ultrasonic transducer signal conformance in ultrasonic flow rate measuring.Transducer is placed in closed container by the utility model, and the baffle plate of adjustable sound wave path length is designed with a reservoir.The voltage of pumping signal, umber of pulse, frequency, dutycycle are adjusted, then the echo-signal to reflection is handled.Process circuit includes pre-amplification circuit, filter circuit, gain control circuit and peak value sampling circuit.Digital AGC circit is wherein constituted by echo-signal stabilization in identical peak value using circuit by gain control circuit and peak value, the multiplication factor finally according to echo-signal judges the parameter of transducer, and foundation is provided for transducer pairing.Meanwhile, according to the change of sound path under the conditions of identical excitation, the transducer available for selection different tube diameters flowmeter.The utility model has cost low, low in energy consumption, the characteristics of measuring stabilization, high resolution.

Description

A kind of quick measuring circuit of ultrasonic transducer signal

Technical field

The utility model belongs to ultrasonic transducer detection field, is related to a kind of ultrasonic transducer signal and quickly measures electricity Road.

Background technology

Ultrasonic transducer is a kind of acoustic-electric conversion equipment, is widely used in ultrasonic flowmeter.Ultrasonic flowmeter Flow information is calculated using the ultrasonic signal received, is a kind of contactless flowmeter, small with crushing, precision is high, Range ratio is big to wait outstanding advantages, in international trade and engineer applied, has broad prospects.

The uniformity of so-called transducer, just refers to the static characteristic of two transducers and the similarity degree of dynamic characteristic.Such as The uniformity of two ultrasonic transducers of fruit selection is poor, then two sound channel othernesses of transducer are larger, causes to receive echo Shape, amplitude, phase, the difference of the parameter such as frequency.Very big difficulty is also brought to the design of hardware and the processing of software. The Installation And Test also to flowmeter is made troubles simultaneously, is caused the error of measurement or even is made flowmeter cisco unity malfunction.

Transducer comparison of coherence in actual production is poor, and transmitting acoustic wave energy and receiving sensitivity ratio are relatively low therefore right It is a relatively effective approach for improving instrument performance that the uniformity of ultrasonic transducer, which carries out necessary screening,.It is super in measurement Usually require to use special admittance instrument or general electric impedance analyzer during the uniformity of acoustic wave transducer steady-state characteristic.Due to The parameter of transducer is more, and the uniformity result obtained by electric impedance analyzer is not accurate enough, and existing transducer impedance Specificity analysis instrument is generally very expensive.

The content of the invention

The purpose of this utility model is to provide a kind of ultrasonic transducer circuitry for signal measurement, consistent for transducer signal Property test, improve screening simplification, reduce testing cost.

The utility model technical solution adopted for solving the technical problem is：

Circuit of the present utility model includes single-chip microcomputer, drive circuit, analog switch switching circuit, pre-amplification circuit, band Bandpass filter circuit, gain control circuit, peak value sampling circuit.Ultrasonic transducer two ends are connected with drive circuit output end, together When be connected with two inputs of analog switch switching circuit, analog switch switching circuit is output as echo-signal Signal+ And Signal-, two-way echo-signal enters pre-amplification circuit, and signal V1 is output as after differential amplification, and signal V1 passes through band Signal V2 is output as after bandpass filter circuit, signal V2 is output as signal V3 after entering gain control circuit；Signal V3 enters peak value Signal V4 is output as after sample circuit, gain control circuit and peak value sampling circuit constitute digital AGC circit；Signal V4 is echo The crest voltage of signal, is directly connected to the AD sample ports of single-chip microcomputer, drive circuit, gain control circuit and peak value sampling circuit It is controlled by single-chip microcomputer.

The beneficial effects of the utility model are：

The utility model is simple in construction, from the amplitude intensity of actual ghosts signal, by the driving for adjusting transducer Voltage, frequency, dutycycle, umber of pulse obtains the parameter of transducer under different condition.Transducer signal can intuitively be observed Feature, the preferable transducer of the degree of consistency is filtered out with this, low with cost, low in energy consumption, measurement is stable, high resolution Feature.

Brief description of the drawings

Fig. 1 is transducer pipe laying schematic diagram；

Fig. 2 is measuring system theory diagram；

Fig. 3-9 is the physical circuit of module in system principle diagram.

Embodiment

The utility model is further illustrated below in conjunction with accompanying drawing.

Reference picture 1, transducer is coaxially mounted in closed conduit, and duct length is 200mm, a diameter of 50mm, internal For the air under normal temperature and pressure.Baffle plate in pipeline can be axially moveable, the length to adjust sound wave reflection path.It is to be measured Two pins T+ and T- of ultrasonic sensor be linked into circuit.

Reference picture 2, the workflow of whole system is:Single-chip microcomputer SPI (1) communication interface adjusts digital regulation resistance, changes Driving voltage, while producing PWM control drive circuits, makes transducer obtain driving voltage T+ and T-.Single-chip microcomputer passes through EN1 ports The sequential of analog switch switching circuit is controlled, makes to enter reception state after exciting in transducer.After sound wave reflects through baffle plate, transducing Device receives echo-signal Signal+ and Signal-, and two paths of signals enters pre-amplification circuit, is output as after differential amplification V1, V1 are output as V2 after bandpass filtering, and single-chip microcomputer SPI (2) communication interface adjusts the gain of gain control circuit, enters V2 Enter and V3 is output as after gain control circuit.Single-chip microcomputer enters V3 by the work schedule of EN2 port controlling peak value sampling circuits V4 is exported after peak value sampling circuit.V4 is the crest voltage of echo-signal, is directly connected to the AD sample ports of monolithic, utilizes monolithic 12 AD conversion that machine is carried measure the peak value of echo.System adjusts multiplication factor by digital AGC circit, makes two-way echo peak Value all reaches a setting value, and shows the relevant parameter of system and echo-signal.

Reference picture 3, single machine unit uses MSP430FG437, and LCD display unit is using the liquid crystal display customized.It is brilliant The Y1 frequency of shaking is 4MHz, and crystal oscillator Y2 frequency is 332.768KHz.The pin of the 1st, 52 and 80 of single-chip microcomputer meets 3V, the 10th, 11, 48th, 53,78 and 79 pin are grounded；The pin of single-chip microcomputer the 8th is connected with electric capacity C3 and crystal oscillator Y2 one end, and the 9th pin is another with crystal oscillator Y2's End is connected with electric capacity C4 one end；The electric capacity C3 other end and electric capacity C4 other end common ground；The pin of single-chip microcomputer the 68th and electricity Hold C2 with crystal oscillator Y1 one end to be connected, the 69th pin is connected with the crystal oscillator Y1 other end and electric capacity C1 one end；Electric capacity C2's is another End and electric capacity C1 other end common ground；Electrochemical capacitor C5 positive pole and the one of electric capacity C6 terminates 3V, and electrochemical capacitor C5's is negative Pole and electric capacity C6 other end ground connection.The pin of single-chip microcomputer the 2nd is connected with V4 ports；The pin of single-chip microcomputer the 3rd is connected with EN1 ports, the 4th pin It is connected with EN2 ports.Single-chip microcomputer the 61st, 62,63 pin respectively with SPI (1) communicate CS1, SCK1, SI1 port be connected.It is single Piece machine the 64th, 66,67 pin respectively with SPI (2) communicate CS2, SCK2, SI2 port be connected.The pin of single-chip microcomputer the 65th connects PWM ends Mouthful；The 12-35 pin of single-chip microcomputer are connected with LCD 1-24 pin respectively, the 25- of the 44-47 pin of single-chip microcomputer respectively with LCD 28 pin are connected.Resistance R1 one end is grounded, and 48 pin of the other end and single-chip microcomputer are connected, the resistance R1 other end simultaneously with single-chip microcomputer 49 pin and R2 one end connection, the R2 other end are connected with 50 pin of single-chip microcomputer and R3 one end simultaneously, the R3 other end and list The 51 pin connection of piece machine.Connect with one end of electrochemical capacitor CD1 positive poles and electric capacity C3；Electrochemical capacitor CD1 negative poles and electric capacity C3's The other end connects with the 53rd pin of single-chip microcomputer；80th pin of single-chip microcomputer connects with one end of electrochemical capacitor CD2 positive poles and electric capacity C4； Electrochemical capacitor CD2 negative poles and electric capacity the C4 other end connect with the 78th pin of single-chip microcomputer.

Reference picture 4, boost chip uses LM2733, and digital regulation resistance uses MCP41050.One end and port of transducer T- connections, the other end is connected with port T+, and electric capacity C7 one end ground connection, the other end connects with T- ends and electric capacity C8 one end simultaneously Connect, electric capacity C8 another termination Vp ports；Metal-oxide-semiconductor T1 and T2 grid are all connected with PWM port, T1, T2 drain electrode all with T+ Port is connected, T1 source ground, and T2 source electrode is connected with one end of Vp ports and electric capacity C9 simultaneously；Electric capacity C9 another termination Ground；LM2733 2 pin ground connection, 5 pin meet 3V, 4 pin connecting resistance R4 one end, R4 another termination 3V, an electric capacity C10 termination Ground, another termination 3V；LM2733 5 pin inductance connect L1 one end, the other end and diode D1 of LM2733 1 pin simultaneously with L1 One end connection, the D1 other end is connected with one end of Vp ports and electric capacity C11 simultaneously, the C11 other end and LM2733 3 pin Connection；Resistance R5 one end ground connection, the R5 other end is connected with LM2733 3 pin and MCP41050 6,7 pin simultaneously； MCP41050 8 pin meet 3V, and 5 pin connect Vp ports, and 4 pin ground connection, 3 pin connect SI1 ports, and 2 pin connect SCK1 ports, and 1 pin connects CS1 ends Mouthful.

Reference picture 5, in measurement process, by controlling the sequential of analog switch switching circuit, make transducer alternately as Transmitting and reception are used.When transducer is launched, switch controlling signal puts high level, and two metal-oxide-semiconductors T3, T4 are not turned on, diode It is also at the state of not turning on, T+ and T- signal are isolated.When receiving echo-signal, switch controlling signal EN1 ports are set low Level, two metal-oxide-semiconductor conductings, diode is also switched on, and now the signal of T+ and T- ports can obtain echo letter by diode Number Signal+ and Signal-.Metal-oxide-semiconductor T3 and T4 grid are all connected with EN1 ports, and T3, T4 source electrode all meet 3V；T3 leakage Pole is connected with resistance R6 one end, and the R6 other end be connected with diode D2, D3 positive pole simultaneously, D2 negative pole with and meanwhile with electricity Hinder R8 one end and electric capacity C12 one end connection, R8 other end ground connection, C12 another termination T+ ports；D3 negative pole with it is same When be connected with one end of Signal+ ports and resistance R9, R9 other end ground connection；T4 drain electrode is connected with resistance R7 one end, The R7 other end is connected with diode D4, D5 positive pole simultaneously, D5 negative pole and one end simultaneously with resistance R11 and electric capacity C13 One end connection, R11 the other end ground connection, C13 another termination T- ports；D4 negative pole with simultaneously with Signal- ports and Resistance R10 one end connection, R10 other end ground connection.

Reference picture 6, pre-amplification circuit uses instrument amplifier AD620.Indirect resistance R14 in AD620 1 pin and 8 pin, 4 pin are grounded, and 5 pin meet 1.5V, and 6 pin connect V1 ports, and 7 pin are connected with 3V and electrochemical capacitor C14 anode simultaneously, and C14 negative terminal connects Ground；Voltage-regulator diode D6, D7 negative pole meet 3V, and the negative pole of D6, D7 positive pole respectively with voltage-regulator diode D8, D9 is connected, D8, D9 Plus earth；AD620 3 pin are connected with D7 positive pole and resistance R12 one end simultaneously, R12 another termination Signal+ ends Mouthful；AD620 4 pin are connected with D8 negative pole and resistance R13 one end simultaneously, R13 another termination Signal- ports.

Reference picture 7, bandwidth-limited circuit uses rail-to-rail low-power consumption high speed amplifier OPA836, according to the humorous of actual transducer Vibration frequency scope, designs the centre frequency of bandpass filter.OPA836 2 pin ground connection, 3 pin meet 1.5V, and 5 pin and 6 pin meet 3V, 1 Pin connects electric capacity C18 one end, C18 another termination V2 ports；Resistance R18 one end ground connection, R18 another termination capacitor C17 With resistance R17 one end, C17 and the R17 other end connect OPA836 4 pin simultaneously；Electric capacity C15 one end, C15 one end respectively with R17 two ends connection, the C15 other end, C16 other end short circuit are simultaneously connected with resistance R15, R16 one end simultaneously, and R15 is another One end is connected with V1 ports, R16 other end ground connection.

Reference picture 8, the amplifier of gain control circuit equally uses amplifier OPA836, and digital regulation resistance is used MCP41100.The gain of circuit and the proportional relation of the resistance of digital regulation resistance.Single-chip microcomputer adjusts numeral by SPI communication interfaces Potentiometer, changes circuit gain, the amplitude of signal is reached predetermined size.OPA836 2 pin ground connection, 4 pin meet 1.5V, 5 pin 3V is met with 6 pin, 1 pin and 3 pin connect electric capacity C18 two ends respectively；An electric capacity C19 termination V2 ports, C19 flow one is terminated Resistance R19 one end, R19 another termination OPA836 3 pin, OPA836 3 pin connect with MCP41100 6 pin and 7 pin simultaneously Connect；MCP41100 8 pin meet 3V, and 4 pin ground connection, 3 pin connect SI2 ports, and 2 pin connect SCK2 ports, and 1 pin connects CS2 ports, and 5 pin connect electricity Hinder R20 one end, R20 another termination V3 ports.

Reference picture 9, peak value sampling circuit is using two pieces of low-power consumption high-speed comparator OPA357.When input voltage is raised, Diode current flow, capacitor fast charging simultaneously maintains input voltage.When input voltage is reduced, diode cut-off, electric capacity is without filling Electric discharge, output voltage remains unchanged.So after the completion of circuit plays the role of peak holding, one-time detection, passing through discharge control terminal Opening metal-oxide-semiconductor makes the detection of electric capacity electric discharge preparation next time.OPA836 2 pin ground connection, 3 pin connect V3 ports, and 5 pin and 6 pin meet 3V, 1 pin is connected with diode D10 positive pole, and 4 pin are connected with resistance R21 one end, R21 another termination V4 ports；OPA357(2) 2 pin ground connection, 5 pin and 6 pin meet 3V, and 1 pin and 4 pin connect V4 ports simultaneously, and 3 pin are connected with diode D10 negative pole.Metal-oxide-semiconductor T5 Source ground, grid connects EN2 ports, and drain electrode connecting resistance R22 one end, the R22 other end connects OPA357 (2) 3 pin simultaneously With electric capacity C21 one end, the C21 other end is grounded.

Operation principle is as follows：Transducer to be measured is coaxially mounted in closed conduit, regulate baffle plate and transducer away from From.Transducer two ends（T+ and T-）It is connected with drive circuit output end, while two with the first path analoging switch switching circuit Input is connected, and switching circuit is output as echo-signal Signal+ and Signal-, and two paths of signals enters pre-amplification circuit, V1 is output as after differential amplification, V1 is output as V2 after bandpass filtering, and V2 is output as V3 after entering gain control circuit. V3 is output as V4 after entering peak value sampling circuit.V4 is the crest voltage of echo-signal, is directly connected to the AD sampling ends of single-chip microcomputer Mouth carries out digital-to-analogue conversion, obtains the crest voltage of echo-signal.System is adjusted in digital AGC circit according to the size of crest voltage Digital regulation resistance, change echo-signal multiplication factor, crest voltage is maintained at the value of setting.Meanwhile, shown on LCD System drive voltage, frequency, dutycycle, umber of pulse, the parameter such as digital regulation resistance is used as the assessment foundation of transducer uniformity.

Claims (1)

1. a kind of ultrasonic transducer circuitry for signal measurement, it is characterised in that：It includes single-chip microcomputer, drive circuit, analog switch Switching circuit, pre-amplification circuit, bandwidth-limited circuit, gain control circuit and peak value sampling circuit；

Ultrasonic transducer two ends are connected with drive circuit output end, while connecting with two inputs of analog switch switching circuit Connect, analog switch switching circuit is output as echo-signal Signal+ and Signal-, two-way echo-signal enters preposition amplification Circuit, is output as signal V1 after differential amplification, and signal V1 is output as signal V2 after bandwidth-limited circuit, and signal V2 enters Enter to be output as signal V3 after gain control circuit；Signal V3 is output as signal V4, described gain after entering peak value sampling circuit Circuit and peak value sampling circuit is controlled to constitute digital AGC circit；Signal V4 is the crest voltage of echo-signal, is directly connected to monolithic The AD sample ports of machine；Drive circuit, gain control circuit and peak value sampling circuit are controlled by single-chip microcomputer.