Ultrasonic signal switching circuit and ultrasonic meter

Abstract

The embodiment of the utility model provides an ultrasonic signal switching circuit and an ultrasonic meter. The ultrasonic signal switching circuit comprises a driving circuit, two receiving and transmitting circuits, a signal processing circuit and a bleeder circuit, each transmitting and receiving circuit comprises a pair of transmitting branch and receiving branch which are respectively used for transmitting excitation signals output by the driving circuit to the connected ultrasonic transducers and receiving echo signals of the connected ultrasonic transducers; each transmitting branch and each receiving branch comprise at least one analog switch; the input ends of the bleeder circuit and the signal processing circuit are connected with the receiving branches, and the output end of the bleeder circuit is grounded; the drive circuit is used for outputting an enable signal to one of the transmit-receive circuits, the signal processing circuit and the bleeder circuit. By adding the bleeder circuit, the ultrasonic transducer is prevented from being excited in advance due to channel crosstalk, noise in echo signals is further reduced, and the signal-to-noise ratio of the echo signals is improved.

Description

Technical Field

[0001] This application relates to the field of ultrasonic metrology technology, and in particular to an ultrasonic signal switching circuit and an ultrasonic meter. Background Technology

[0002] An ultrasonic meter is an instrument that uses ultrasonic technology for measurement, commonly used for fluid measurement. When ultrasonic waves propagate in a fluid, their propagation is affected by the fluid's flow velocity. Therefore, ultrasonic meters typically use a pair of ultrasonic transducers, which act as either transmitting or receiving transducers in a time-division multiplexing manner. By measuring the time difference between the forward and reverse propagation of ultrasonic waves, the real-time flow rate of the fluid is calculated.

[0003] Currently, two analog switches are typically used to control the operating mode of ultrasonic transducers: one analog switch acts as the transmitting circuit, and the other as the receiving circuit. The transmitting and receiving transducers are switched by selecting the output channel of the analog switch. However, when the ultrasonic transducer is used as a transmitting transducer, a large excitation voltage is required to emit ultrasonic waves. This large excitation voltage can generate crosstalk between channels, causing the receiving transducer to be prematurely excited and emit noise signals, which are then superimposed on the echo signal, resulting in low measurement accuracy. Utility Model Content

[0004] This application provides an ultrasonic signal switching circuit and an ultrasonic meter. By using multiple analog switches, the transmitting and receiving branches of two ultrasonic transducers are isolated, reducing crosstalk between the branches. At the same time, when no echo signal is received, the receiving ultrasonic transducer is grounded through a bleed circuit to prevent the receiving ultrasonic transducer from being prematurely excited, thereby introducing noise into the echo signal.

[0005] In a first aspect, embodiments of this application provide an ultrasonic signal switching circuit, comprising: a driving circuit, two transceiver circuits, a signal processing circuit, and a bleeder circuit; wherein each transceiver circuit includes a pair of transmitting branches and receiving branches, respectively used to transmit an excitation signal output by the driving circuit to a connected ultrasonic transducer, and to receive an echo signal from the connected ultrasonic transducer; each transmitting branch and receiving branch includes at least one analog switch; the input terminals of the bleeder circuit and the signal processing circuit are connected to each receiving branch, and the output terminal of the bleeder circuit is grounded; the driving circuit is used to output an enable signal to one of the transceiver circuits, the signal processing circuit, and the bleeder circuit respectively.

[0006] In one possible implementation, the bleeder circuit includes an analog switch; the enable terminal of the analog switch of the bleeder circuit and the enable terminal of the signal processing circuit are respectively connected to the first output terminal and the second output terminal of the drive circuit.

[0007] In a possible implementation, the bleeding circuit includes an analog switch; an enable terminal of the analog switch of the bleeding circuit is connected with the first output terminal of the driving circuit, and the first output terminal of the driving circuit is connected with the enable terminal of the signal processing circuit through an inverter.

[0008] In a possible implementation, the analog switch is a single-pole double-throw switch.

[0009] In a possible implementation, the two transceiver circuits include a first transceiver circuit and a second transceiver circuit; the analog switch in the transmitting branch includes an input terminal, a first output terminal and a second output terminal; the input terminal of the analog switch in the transmitting branch of the first transceiver circuit is connected with the excitation signal output terminal of the driving circuit, the first output terminal is connected with the input terminal of the next analog switch or the ultrasonic transducer in series, and the second output terminal is left floating; the input terminal of the analog switch in the transmitting branch of the second transceiver circuit is connected with the excitation signal output terminal of the driving circuit, the second output terminal is connected with the input terminal of the next analog switch or the ultrasonic transducer in series, and the first output terminal is left floating.

[0010] In a possible implementation, each transmitting branch and receiving branch includes a plurality of analog switches in series.

[0011] In a possible implementation, the enable terminals of the analog switches of the receiving branch and the transmitting branch are connected with the third output terminal of the driving circuit.

[0012] In a possible implementation, the signal processing circuit includes a first capacitor, a voltage biasing unit and an amplifier; the echo signal input into the signal processing circuit is pulled up to a positive potential level by the voltage biasing unit after passing through the first capacitor.

[0013] In a possible implementation, the voltage biasing unit includes a first resistor, a second resistor, a third resistor and a second capacitor; a first terminal of the first resistor is connected with a voltage source, a second terminal of the first resistor is connected with a first terminal of the second resistor and a first terminal of the third resistor respectively, a second terminal of the second resistor is connected with a ground, a second terminal of the third resistor is connected with an input terminal of the amplifier; and the first capacitor is connected with the third resistor in parallel.

[0014] In a second aspect, an embodiment of the present application provides an ultrasonic watch, which includes an ultrasonic transducer and the ultrasonic signal switching circuit provided in the first aspect.

[0015] The ultrasonic signal switching circuit and the ultrasonic watch provided by the embodiment of the present application, the ultrasonic signal switching circuit comprises a driving circuit, two transceiving circuits, a signal processing circuit and a bleeding circuit, wherein each transceiving circuit comprises a pair of sending branches and receiving branches, the sending branches are connected with the driving circuit and the ultrasonic transducer, the receiving branches are connected with the ultrasonic transducer, the bleeding circuit and the signal processing circuit, each sending branch and receiving branch comprises at least one analog switch, the excitation signal sent by the driving circuit and the echo signal of the ultrasonic transducer are transmitted along different transceiving circuits in time, so that the switching of the ultrasonic transducer can be realized; the output end of the bleeding circuit is connected with the ground, so as to release the electrical signal input to the bleeding circuit; the driving circuit is used for outputting an enable signal to one of the transceiving circuit, the signal processing circuit and the bleeding circuit, so as to control the start or stop of each circuit, wherein the enable signals received by the bleeding circuit and the signal processing circuit make the bleeding circuit and the signal processing circuit realize time-sharing work. By using at least four analog switches to isolate each branch, the circuit is simple, the reliability is high, the channel crosstalk between the branches is reduced, at the same time, before the signal processing circuit receives the echo signal, the electrical signal in the branch is released through the bleeding circuit, so that the receiving ultrasonic transducer is prevented from being excited in advance due to the channel crosstalk, the noise signal caused by the channel crosstalk is reduced, and the signal-to-noise ratio of the echo signal is improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one embodiment consistent with the present application and, together with the description, serve to explain the principles of the application.

[0017] Figure 1 An application scenario schematic diagram of an ultrasonic watch provided by the embodiment of the present application;

[0018] Figure 2 A structure schematic diagram of an ultrasonic signal switching circuit provided by the embodiment of the present application;

[0019] Figure 3 A structure schematic diagram of a transceiving circuit provided by the embodiment of the present application;

[0020] Figure 4a A schematic diagram of an enable signal input to the bleeding circuit and the signal processing circuit provided by the embodiment of the present application;

[0021] Figure 4b A schematic diagram of another enable signal input to the bleeding circuit and the signal processing circuit provided by the embodiment of the present application;

[0022] Figure 5 A circuit structure diagram of the bleeding circuit and the signal processing circuit provided by the embodiment of the present application;

[0023] Figure 6A circuit diagram of another discharge circuit provided in an embodiment of this application;

[0024] Figure 7 This is a schematic diagram of another transceiver circuit provided in an embodiment of this application;

[0025] Figure 8 A circuit structure diagram of a transceiver circuit provided in an embodiment of this application;

[0026] Figure 9 A circuit diagram of an ultrasonic signal switching circuit with six analog switches provided in an embodiment of this application;

[0027] Figure 10 A structural diagram of another ultrasonic signal switching circuit with six analog switches provided in this application embodiment;

[0028] Figure 11 A structural diagram of an ultrasonic signal switching circuit with eight analog switches provided in an embodiment of this application;

[0029] Figure 12 This is a schematic diagram of the structure of an ultrasonic meter provided in an embodiment of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 110: Ultrasonic transducer;

[0032] 200: Ultrasonic signal switching circuit; 210: Drive circuit; 220: Transceiver circuit; 221: Analog switch; 230: Signal processing circuit; 240: Discharge circuit; 250: First transceiver circuit; 260: Second transceiver circuit;

[0033] 300: Housing;

[0034] 400: Pipeline;

[0035] 500: Screen.

[0036] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0037] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application.

[0038] When using ultrasonic meters for fluid measurement, a pair of ultrasonic transducers are typically installed. These transducers can convert electrical energy into ultrasonic waves or vice versa; one transducer can function as both a transmitter and a receiver. By switching the operating states (transmit or receive) of the transducers, the flight time of ultrasonic waves propagating in different directions can be obtained. The propagation direction refers to the direction of ultrasonic wave propagation relative to the fluid direction, including both with and against the flow. The real-time flow rate of the fluid can be calculated using the flight times of the ultrasonic waves propagating in different directions.

[0039] Figure 1 This is a schematic diagram illustrating an application scenario of an ultrasonic meter provided in an embodiment of this application, such as... Figure 1 As shown, the specific application scenario of this application is for fluid measurement, such as an ultrasonic meter that emits ultrasonic waves in different directions at different times, and calculates the real-time flow rate of the fluid by measuring the propagation time of each ultrasonic wave. The fluid includes liquids and gases, such as water and natural gas. Figure 1 As shown, assuming the fluid direction is in the direction pointed by the large arrow, when Figure 1 When the ultrasonic transducer 110 located at the top (referred to as the first ultrasonic transducer) is used as the transmitting transducer, Figure 1 The ultrasonic transducer 110 located at the bottom (referred to as the second ultrasonic transducer) can receive ultrasonic waves propagating in the opposite direction of the current; when the second ultrasonic transducer acts as a transmitting transducer, the first ultrasonic transducer can receive ultrasonic waves propagating in the same direction as the current. By processing and calculating the received ultrasonic waves with different propagation directions, the propagation directions ( Figure 1 The propagation time of ultrasound (in the direction indicated by the dashed arrow), for example... Figure 1 The propagation times t1 and t2 are given. The propagation time of ultrasound waves in different directions is related to the fluid velocity v; the propagation time decreases with the flow and increases with the flow, meaning t1 is greater than t2. Based on these propagation times, the real-time fluid velocity can be determined, and thus the real-time flow rate can be calculated.

[0040] To achieve the switching of the ultrasonic transducer's operating state at different times, it is necessary to switch the connection state between the ultrasonic transducer and the front-end drive circuit and the back-end signal processing circuit at different times. The front-end drive circuit selects an ultrasonic transducer and sends an excitation signal to it, causing the ultrasonic transducer to emit ultrasonic waves. Another ultrasonic transducer receives the ultrasonic waves and forms an echo signal, which is then transmitted to the back-end signal processing circuit for processing.

[0041] The commonly used switching mode is to use two channels of an analog switch to realize. Specifically, the driving circuit at the front end is connected to the corresponding ultrasonic transducer through two output terminals of the analog switch, and the two ultrasonic transducers are connected to the signal processing circuit at the back end through the two output terminals of the analog switch. By selecting the output terminal of the analog switch that is turned on, the excitation signal is sent to the ultrasonic transducer corresponding to the output terminal. However, since the excitation signal required as a transmitting transducer is generally a large signal, and the echo signal formed as a receiving transducer is a small signal, generally an mV level signal, the large signal will cause crosstalk between the two output terminals of the analog switch, so that the receiving transducer is excited in advance and a noise signal is emitted. The switching mode has large signal interference in actual application, the signal-to-noise ratio of the echo signal received by the signal processing circuit is low, and the accuracy of fluid metering is affected.

[0042] To solve the above problems, the embodiment of the present application provides an ultrasonic signal switching circuit. By using two transceiving circuits composed of multiple analog switches, when the driving circuit selects the ultrasonic transducer connected to the transmitting branch in one transceiving circuit as the transmitting transducer, the transmitting branch and the receiving branch in the other transceiving circuit are isolated, reducing the crosstalk between the channels. At the same time, a bleeder circuit is added to release the electrical signal in the branch to the ground when the signal processing circuit is not enabled, avoiding the receiving ultrasonic transducer from being excited in advance due to channel crosstalk, thereby reducing the noise in the echo signal and improving the signal-to-noise ratio of the echo signal.

[0043] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0044] Figure 2 A structure diagram of an ultrasonic signal switching circuit provided by the embodiment of the present application is shown in FIG. 1. Figure 2 As shown in the figure, the ultrasonic signal switching circuit includes a driving circuit 210, two transceiving circuits 220, a signal processing circuit 230, and a bleeder circuit 240.

[0045] Each transceiving circuit 220 includes a pair of transmitting branch and receiving branch, which are used to transmit the excitation signal outputted by the driving circuit 210 to the connected ultrasonic transducer 110 and receive the echo signal of the connected ultrasonic transducer 110 respectively; each transmitting branch and receiving branch includes at least one analog switch 221; the input end of the bleeding circuit 240 and the signal processing circuit 230 is connected with each receiving branch, and the output end of the bleeding circuit 240 is grounded; the driving circuit 210 is used to output an enable signal to one of the transceiving circuit 220, the signal processing circuit 230 and the bleeding circuit 240; the enable signals received by the bleeding circuit 240 and the signal processing circuit 230 are opposite in time sequence.

[0046] The excitation signal is an electrical signal used to drive the ultrasonic transducer 110 to emit ultrasonic waves. Specifically, in the ultrasonic transducer 110, the excitation signal makes the ultrasonic transducer 110 vibrate, thereby generating ultrasonic waves. The generated ultrasonic waves are received by another ultrasonic transducer 110 in a certain propagation direction (downstream or upstream). The echo signal is an electrical signal formed by the ultrasonic transducer 110 according to the received ultrasonic waves. Specifically, the received ultrasonic waves make the ultrasonic transducer 110 deform or vibrate, so that the ultrasonic transducer 110 generates electric charges, and the generated electric charges are converted into the echo signal. Exemplarily, the excitation signal and the echo signal can be square wave, sine wave or pulse wave, etc.

[0047] The enable signal is a control signal used to start an electronic component. Generally, the enable signal is a fixed level, such as high level or low level. The specific enable signal is determined according to the selected device.

[0048] The driving circuit 210 includes a master control chip, which has multiple I / O (Input / Output) ports, each of which can be used as an input end or an output end of the driving circuit 210. The master control chip can be a single-chip microcomputer (MCU) or a field programmable gate array (FPGA). According to the function of the output end, the output end of the driving circuit 210 can be divided into an enable output end, an excitation signal output end, etc.

[0049] The driving circuit 210 is used to control and drive other circuits. For example, one enable output of the driving circuit 210 can be connected to the enable terminals of the two transceiving circuits 220 to control the selected transceiving circuit 220; the excitation signal output can be connected to the input terminals of the two transceiving circuits 220 to send excitation signals to the ultrasonic transducers 110 connected to the transmitting branch of the transceiving circuit 220; one enable output can be connected to the enable terminal of the discharge circuit 240, and one enable output can be connected to the enable terminal of the signal processing circuit 230 to control the discharge circuit 240 and the signal processing circuit 230 to work.

[0050] For example, as shown in Figure 2 , the driving circuit 210 can select one of the transceiving circuits 220 by sending enable signal 1 and enable signal 2 to the selected transceiving circuit 220; the driving circuit 210 can start the discharge circuit 240 by outputting enable signal 3 to the discharge circuit 240; the driving circuit 210 can start the signal processing circuit 230 by outputting enable signal 4 to the signal processing circuit 230.

[0051] In some embodiments, the driving circuit 210 is used to output enable signals to the transceiving circuit 220, the signal processing circuit 230 and the discharge circuit 240, and the enable output for outputting the enable signal can be one output or multiple outputs. The driving circuit 210 is also used to output excitation signals to the two transceiving circuits 220, and the excitation signal output for outputting the excitation signal can be one or two outputs, preferably one output.

[0052] Continuing to refer to Figure 2 , the transmitting branch is a branch for sending excitation signals to the connected ultrasonic transducer 110, such as the transmitting branch ① and the transmitting branch ② in Figure 2 . The receiving branch is a branch for sending the echo signals of the connected ultrasonic transducer 110 to the signal processing circuit 230 and the discharge circuit 240, such as the receiving branch ③ and the receiving branch ④ in Figure 2 .

[0053] The transceiving circuit 220 is a circuit for transmitting excitation signals and echo signals in a fixed transmission path, such as the part in the dashed box in Figure 2 . For example, the transmitting branch ① and the receiving branch ④ in Figure 2 form a transceiving circuit 220; the transmitting branch ② and the receiving branch ③ form another transceiving circuit 220.

[0054] The analog switch 221 is an electronic component that can selectively connect or disconnect an electrical signal path. The analog switch 221 can be a single-pole single-throw switch, a single-pole double-throw switch, a single-pole multi-throw switch, etc. The analog switch 221 can also be implemented using a transistor, a field effect transistor, or an integrated chip. For example, the analog switch 221 can be implemented using one NMOS transistor and one PMOS transistor to realize the switching function.

[0055] Specifically, continuing to refer to Figure 2 , Figure 2 For example, in a branch including an analog switch 221, the input end of the analog switch 221 of the transmitting branch ① and ② is connected to the driving circuit 210, and the output end of the analog switch 221 of the transmitting branch ① and ② is connected to the ultrasonic transducer 110 connected to the branch, for example, the output end of the analog switch 221 in the transmitting branch ① is connected to an ultrasonic transducer 110, and the output end of the analog switch 221 in the transmitting branch ② is connected to an ultrasonic transducer 110. The input end of the analog switch 221 of the receiving branch is connected to the ultrasonic transducer 110 connected to the branch, and the output end of the analog switch 221 of the receiving branch is connected to the signal processing circuit 230 and the discharge circuit 240.

[0056] The enable end of the transceiver circuit 220 can be the enable end of each analog switch 221 in the transceiver circuit 220. The enable end of each transceiver circuit 220 can be connected to a plurality of enable output ends of the driving circuit 210, or can be connected to one enable output end of the driving circuit 210.

[0057] For example, Figure 3 A structure diagram of a transceiver circuit provided by an embodiment of the present application is shown. As can be seen from Figure 2 and Figure 3 The analog switch 221 includes an input end (In1-In4) in Figure 3 , an output end (O1-O4) in Figure 3 , and an enable end (En1 and En2) in Figure 3 . Each input end is used to receive an excitation signal sent by the driving circuit 210, each output end is used to send the received excitation signal to the connected ultrasonic transducer 110, and each enable end is used to turn on the analog switch 221 when the enable end receives an enable signal. For example, when an enable signal is sent to En1, the excitation signal of the driving circuit 210 can enter the transceiver circuit 220 through the input end In1, and be sent to the connected ultrasonic transducer 110 through the output end O1, and excite ultrasonic waves. When another ultrasonic transducer 110 receives the ultrasonic waves and generates a return signal, the return signal is transmitted to the signal processing circuit 230 and the discharge circuit 240 at the back end through the input end In4 and the output end O4.

[0058] In this application, the enable terminals of the analog switches 221 in a transceiver circuit 220 are connected together, which can be regarded as the enable terminals of the transceiver circuit 220. The drive circuit 210 includes two enable output terminals. Figure 3 E1 and E2 in the circuit 220 are respectively connected to the enable terminals of the analog switches 221 in each transceiver circuit 220. Figure 3 The connected ultrasonic transducer 110 is configured to be a transmitting transducer or a receiving transducer by sending an enable signal to different transceiver circuits 220.

[0059] When one enable output terminal of the drive circuit 210 outputs an enable signal to En1, the transceiver circuit 220 corresponding to En1 terminal is turned on, that is, the transceiver circuit 220 composed of the transmitting branch ① and the receiving branch ④; when one enable output terminal of the drive circuit 210 outputs an enable signal to En2 terminal, the transmitting branch ② and the receiving branch ③ corresponding to En2 terminal are turned on.

[0060] In one example, a multi-output channel analog switch 221 can be selected, such as a single-pole double-throw switch or a single-pole multi-throw switch. The output channel refers to the path through which the electrical signal is output from the analog switch 221. This is distinct from... Figure 3 In cases where the transceiver circuit 220 needs to be switched through two enable output terminals, in this embodiment, the drive circuit 210 can switch the transceiver circuit 220 through only one enable output terminal, connecting the enable terminals of the analog switches 221 of each branch to the enable output terminal of the drive circuit 210.

[0061] Specifically, the multi-output channel analog switch 221 turns on its output channel according to the potential level of the input enable signal. Based on this, in this application, the same output terminal of the analog switch 221 in the same transceiver circuit 220 is connected together, and the analog switches 221 in different transceiver circuits 220 are connected to different channels. With this connection, one enable output terminal of the drive circuit 210 outputs the same enable signal to each transceiver circuit 220, turning on the output channel of the analog switch 221 connected to one transceiver circuit 220 and turning off the output channel of the analog switch 221 connected to another transceiver circuit 220. Thus, one transceiver circuit 220 can be turned on and another off with a single enable signal.

[0062] In this embodiment, the number of analog switches 221 included in each transmitting branch and the number of analog switches 221 included in each receiving branch can be 1, 2 or 3, etc.

[0063] For example, if the number of analog switches 221 in each branch is multiple, the multiple analog switches 221 in each branch are connected in series. The two ends of the multiple analog switches 221 connected in series are connected with the driving circuit 210 and the corresponding ultrasonic transducer 110 respectively, or are connected with the corresponding ultrasonic transducer 110, the signal processing circuit 230 and the discharge circuit 240 respectively.

[0064] In the embodiment, the enable signal input to the enable end of the transceiver circuit 220 can be a timing signal, so that the ultrasonic signal switching circuit can make each ultrasonic transducer 110 work alternately as a transmitting transducer and a receiving transducer in a certain period, and the automatic time-sharing work of the ultrasonic transducer 110 can be realized. For example, the enable signal is a square wave signal with a fixed frequency, when the signal is at a high level, one transceiver circuit 220 is turned on, and when the signal is at a low level, the other transceiver circuit 220 is turned on.

[0065] The signal processing circuit 230 is a circuit for processing the echo signal. For example, the echo signal can be amplified and filtered by the signal processing circuit 230.

[0066] The signal processing circuit 230 can include an amplifier and its peripheral configuration circuit, a filter circuit and the like. The amplifier and its peripheral configuration circuit are used for amplifying the echo signal input to the amplifier, and the filter circuit is used for allowing only signals with a specific frequency to pass.

[0067] The signal processing circuit 230 further includes an enable end in addition to the input end and the output end, which is used for making the signal processing circuit 230 work only when valid signals arrive. Specifically, since the ultrasonic transducer 110 works in time-sharing mode, only the echo signal in a fixed time period is a valid signal, and noise signals can exist in the circuit in the remaining time period. If the noise signals are also processed, unnecessary power consumption will be caused, and a large noise signal can be generated, which reduces the accuracy of the final fluid metering. The enable end can be used to send an enable signal to the signal processing circuit 230 only in a fixed time.

[0068] The discharge circuit 240 is a circuit for releasing electrical signals in the circuit. Specifically, the discharge circuit 240 can release the crosstalk signal and other stored electrical signals in the circuit. The discharge circuit 240 can be composed of analog switches, specifically single-pole double-throw switches, single-pole single-throw switches, field effect tubes or triodes and the like.

[0069] In some embodiments, the bleeding circuit 240 can release the electrical signal output to the bleeding circuit 240 when the signal processing circuit 230 is not working or the echo signal has not been transmitted to the signal processing circuit 230. For example, the bleeding circuit 240 includes an enable terminal, and when the signal processing circuit 230 is not working or the echo signal has not been transmitted to the signal processing circuit 230, the output terminal of the receiving branch is grounded by inputting an enable signal to the enable terminal to control the bleeding circuit to be turned on.

[0070] In an example, Figure 4a A schematic diagram of an enable signal input to the bleeding circuit and the signal processing circuit is provided for the embodiments of the present application. It is assumed that the enable signal (the enable signal 5 input to the signal processing circuit 230 and the enable signal 6 input to the bleeding circuit 240) is high, indicating that the bleeding circuit 240 is turned on and the signal processing circuit 230 is working. As shown in Figure 4a The timing of the enable signal input to the bleeding circuit 240 and the signal processing circuit 230 is reversed to turn on the bleeding circuit 240 when the signal processing circuit 230 is not working. As shown in Figure 4a The time at which the signal processing circuit 230 receives the enable signal is T1, and the input of the enable signal to the bleeding circuit 240 can be stopped at T1, i.e., a low level is input to the enable terminal of the bleeding circuit 240.

[0071] In another example, the time at which the signal processing circuit 230 receives the enable signal can be earlier than the time at which the echo signal is received, so that the signal processing circuit 230 has a time window before receiving the echo signal to stabilize the signal processing circuit 230. For this scenario, the timing of the enable signal of the bleeding circuit 240 and the enable signal of the signal processing circuit 230 is not completely reversed.

[0072] Figure 4b Another schematic diagram of an enable signal input to the bleeding circuit and the signal processing circuit is provided for the embodiments of the present application. As shown in Figure 4b The enable signals of the bleeding circuit 240 and the signal processing circuit 230 can overlap, so that the bleeding circuit can be turned off at the time T2 at which the signal processing circuit 230 receives the enable signal. Specifically, the enable signal can still be input to the bleeding circuit 240 from T2 to T1.

[0073] Although the two transmission branches are isolated in the embodiment, in actual operation, if the excitation signal is large, or the signal wire distance is close due to the limitation of the board space, there may be partial channel crosstalk, so that the ultrasonic transducer 110 is excited in advance, or if the application scene interference is large, there may be other noise signals. In order to further reduce the influence of channel crosstalk and other noise signals, the input end of the receiving transducer can be grounded when the signal processing circuit 230 is not working, that is, during the period when the ultrasonic transducer 110 is not receiving, so that the receiving transducer will not be excited in advance and will not receive noise signals.

[0074] The ultrasonic signal switching circuit provided by the embodiment of the application includes a driving circuit 210, two transceiver circuits 220, a signal processing circuit 230 and a bleeding circuit 240. Each transceiver circuit 220 includes a pair of transmission branches and receiving branches. The transmission branches are connected to the driving circuit 210 and the ultrasonic transducer 110. The receiving branches are connected to the ultrasonic transducer 110, the bleeding circuit 240 and the signal processing circuit 230. Each transmission branch and receiving branch includes at least one analog switch 221. The excitation signal transmitted by the driving circuit 210 and the echo signal of the ultrasonic transducer 110 are transmitted along different transceiver circuits 220 in time division manner, so that the switching of the ultrasonic transducer 110 can be realized. The output end of the bleeding circuit 240 is grounded to release the electrical signal input to the bleeding circuit 240. The driving circuit 210 is used to output an enable signal to one of the transceiver circuits 220, the signal processing circuit 230 and the bleeding circuit 240, so as to control the start or stop of each circuit. The enable signals received by the bleeding circuit 240 and the signal processing circuit 230 make the bleeding circuit 240 and the signal processing circuit 230 start working at different times. By using at least four analog switches 221 to isolate each branch, the circuit is simple and has high reliability, reduces the channel crosstalk between the branches, and releases the electrical signal in the branch through the bleeding circuit 240 when the signal processing circuit 230 is not enabled, so as to avoid the receiving ultrasonic transducer 110 from being excited in advance due to channel crosstalk, reduce the noise signal caused by channel crosstalk, and improve the signal-to-noise ratio of the echo signal.

[0075] Optionally, the bleeding circuit 240 includes an analog switch. The enable end of the analog switch of the bleeding circuit 240 and the enable end of the signal processing circuit 230 are respectively connected to the first output end and the second output end of the driving circuit 210.

[0076] By connecting the enable end of the analog switch of the bleeding circuit 240 and the enable end of the signal processing circuit 230 to the output end of the different driving circuits 210, whether the bleeding circuit 240 and the signal processing circuit 230 work can be controlled by the driving circuit 210.

[0077] Exemplarily, Figure 5A circuit structure diagram of a bleeding circuit and a signal processing circuit is provided in the embodiment. As shown in Figure 5 The bleeding circuit 240 is composed of a chip U9 and a capacitor C18. The capacitor C18 is used to filter the noise of the voltage source VCC_RX, and the chip U9 is used to select the output end NO according to the enable signal input by the pin IN. The pin IN of the chip U9 is connected to the enable output end MCU_CTL of the driving circuit 210, i.e., the first output end. The pin 5 of the signal processing circuit 230 is connected to the enable output end MCU_OPA_EN of the driving circuit 210, i.e., the second output end, through a resistor R10. The resistor R6 is a bleeding resistor, which is used to release the direct current in the echo signal.

[0078] The first output end and the second output end of the driving circuit 210 can output enable signals with different time sequences, so that the bleeding circuit 240 and the signal processing circuit 230 work in different time. For example, when a high level is output to the first output end and a low level is output to the second output end, the signal processing circuit 230 is started, the chip U9 in the bleeding circuit 240 is turned on to make the output end NC of the bleeding circuit 240 suspended; when a low level is output to the first output end and a high level is output to the second output end, the signal processing circuit 230 does not work, the chip U9 in the bleeding circuit 240 is turned on to make the output end NO of the bleeding circuit 240 grounded.

[0079] In the embodiment, the enable end of the analog switch in the bleeding circuit and the enable end of the signal processing circuit 230 are connected to the two output ends of the driving circuit 210 respectively, and the driving signals with different time sequences are output through the two output ends, so that the implementation is simple and the cost is low.

[0080] Optionally, the bleeding circuit 240 includes an analog switch; the enable end of the analog switch of the bleeding circuit 240 is connected to the first output end of the driving circuit 210, and the first output end of the driving circuit 210 is connected to the enable end of the signal processing circuit 230 through an inverter.

[0081] The inverter is a kind of logic gate device, which is used to invert the signal input to the inverter. For digital signals, the inverter can convert the input high level into low level, and convert the input low level into high level.

[0082] The first output end of the driving circuit 210 can be connected to the enable end of the signal processing circuit 230 through an inverter, so that the time sequence of the level of the enable end of the bleeding circuit 240 and the signal processing circuit 230 is inverted, and the bleeding circuit 240 and the signal processing circuit 230 work in different time.

[0083] In the embodiment, the inverter is used to realize the bleeding circuit 240 and the signal processing circuit 230 working in different time, so that the system stability is higher, the control program is not easy to be wrong, and the reliability is high.

[0084] In the above embodiment, the two enable signals can be realized by inverters. According to the above embodiment, in some embodiments, the enable signals input to the signal processing circuit 230 and the bleeder circuit 240 are not completely inverted. In this case, other electronic devices can be added to delay one of the enable signals based on the use of inverters. For example, delay chips, buffers, etc.

[0085] In an embodiment, the enable signals of the bleeder circuit 240 and the signal processing circuit 230 can be designed to have opposite levels, for example, the signal processing circuit 230 is enabled when a high-level enable signal is input, and the bleeder circuit 240 is grounded when a low-level enable signal is input. For example, the output end of the bleeder circuit 240 connected to the ground can be changed, for example, the output end NC is grounded and the output end NO is left floating; or an amplifier with low-level enable can be selected in the signal processing circuit 230. Alternatively, the signal processing circuit 230 and the bleeder circuit 240 can use electronic devices to invert the enable signals. Figure 5

[0086] In an example, the bleeder circuit 240 can also be a field effect transistor.

[0087] When the field effect transistor is used as a switch, it has the advantages of high input impedance, low power consumption and fast switching. For example, for an N-channel field effect transistor, when the gate voltage is higher than the source voltage, the field effect transistor is turned on, and a low impedance channel is formed between the drain and the source.

[0088] For example, Figure 6 Another circuit structure of the bleeder circuit provided in the embodiment of the present application is shown in the figure. As shown in the figure, Figure 6 The port receive-up / down is connected to the two receiving branches and the signal processing circuit 230. When a high-level signal is input to the gate, the field effect transistor Q3 is turned on, a low impedance channel is formed between the drain and the source, and the port receive-up / down is grounded through the field effect transistor Q3; when a low-level signal or a floating signal is input, the field effect transistor Q3 is not turned on, and Q3 and the network receive-up / down are disconnected.

[0089] Optionally, the analog switch 221 is a single-pole double-throw switch.

[0090] ​Optionally, the two transceiving circuits 220 include a first transceiving circuit 250 and a second transceiving circuit 260; the analog switch 221 in the transmitting branch includes an input end, a first output end and a second output end; the input end of the analog switch 221 in the transmitting branch of the first transceiving circuit 250 is connected with the excitation signal output end of the driving circuit 210, the first output end is connected with the ultrasonic transducer 110 or the input end of the next analog switch 221 in series, and the second output end is suspended; the input end of the analog switch 221 in the transmitting branch of the second transceiving circuit 260 is connected with the excitation signal output end of the driving circuit 210, the second output end is connected with the ultrasonic transducer 110 or the input end of the next analog switch 221 in series, and the first output end is suspended.

[0091] The single-pole double-throw switch has one input end and two output ends, and by selecting the output channel of the single-pole double-throw switch that is turned on, switching can be performed between branches connected with the two output ends. The switching mode can be switched by mechanical, electronic or other means, for example, a selection signal can be output to the enable end of the single-pole double-throw switch to switch the output end that is turned on.

[0092] In some embodiments, Figure 7 Another structure schematic diagram of a transceiving circuit is provided for the embodiments of the present application. As shown in Figure 7 The analog switch 221 adopts a single-pole double-throw switch, which includes an input end, a first output end and a second output end. The two transceiving circuits 220 include a first transceiving circuit 250 and a second transceiving circuit 260; the input end In1 of the analog switch 221 in the transmitting branch of the first transceiving circuit 250 is connected with the excitation signal output end of the driving circuit 210, the first output end O11 is connected with the ultrasonic transducer 110, and the second output end O12 is suspended; the input end In2 of the analog switch 221 in the transmitting branch of the second transceiving circuit 260 is connected with the excitation signal output end of the driving circuit 210, the second output end O22 is connected with the ultrasonic transducer 110, and the first output end O21 is suspended.

[0093] In order to make the transmitting branch correspond to the receiving branch one by one, on the basis of the above connection relationship, the input end In4 of the analog switch 221 in the receiving branch of the first transceiving circuit 250 is connected with the connected ultrasonic transducer 110, the first output end O41 is connected with the bleeding circuit 240 and the signal processing circuit 230, and the second output end O42 is suspended. The input end In3 of the analog switch 221 in the receiving branch of the second transceiving circuit 260 is connected with the connected ultrasonic transducer 110, the second output end O32 is connected with the bleeding circuit 240 and the signal processing circuit 230, and the first output end O31 is suspended.

[0094] As Figure 7As shown, the enable terminals of the analog switches 221 can be connected together, and when there is an enable signal to make the first output terminal conductive, the second output terminal is disconnected. In an example, the enable terminals of the analog switches 221 can also be connected to the plurality of enable control terminals of the driving circuit 210 respectively, to control the analog switches 221 respectively.

[0095] As shown in the example, Figure 8 The circuit structure diagram of a transceiver circuit provided by the embodiment of the present application is shown in the figure. For example, the enable terminals of the analog switches 221 are connected to the same enable output terminal (output terminal OE_EN) of the driving circuit 210. Figure 8 The ultrasonic transducers 110 include a first ultrasonic transducer X1 and a second ultrasonic transducer X2, and the analog switches 221 are single-pole double-throw switches, including a chip U1, a chip U3, a chip U5 and a chip U7. One transmitting branch is formed by the chip U1 and a capacitor C1, so that the excitation signal output terminal (output terminal MCU_OUT) of the driving circuit 210 is connected to the first ultrasonic transducer X1 through the output terminal NO of the chip U1; another transmitting branch is formed by the chip U5 and a capacitor C5, so that the excitation signal output terminal is connected to the second ultrasonic transducer X2 through the output terminal NC of the chip U5; one receiving branch is formed by the chip U3 and a capacitor C3, so that the first ultrasonic transducer X1 is connected to the signal processing circuit 230 and the bleeding circuit 240 through the output terminal NC of the chip U3; another receiving branch is formed by the chip U7 and a capacitor C7, so that the second ultrasonic transducer X2 is connected to the signal processing circuit 230 and the bleeding circuit 240 through the output terminal NO of the chip U7.

[0096] Among them, the transmitting branch formed by the chip U1 and the capacitor C1 and the receiving branch formed by the chip U7 and the capacitor C7 form a transceiver circuit 220, in which the first ultrasonic transducer X1 is a transmitting transducer and the second ultrasonic transducer X2 is a receiving transducer; the transmitting branch formed by the chip U5 and the capacitor C5 and the receiving branch formed by the chip U3 and the capacitor C3 form another transceiver circuit 220, in which the second ultrasonic transducer X2 is a transmitting transducer and the first ultrasonic transducer X1 is a receiving transducer.

[0097] If the ultrasonic wave is in the reverse flow direction when the first ultrasonic transducer X1 is used as a transmitting transducer and the second ultrasonic transducer X2 is used as a receiving transducer, by setting the output terminal OE_EN to high level, the echo signal with the propagation direction in the reverse flow direction can be output; by setting the output terminal OE_EN to low level, the echo signal with the propagation direction in the forward flow direction can be output.

[0098] Optionally, the enable terminals of the analog switches 221 of the receiving branch and the transmitting branch are connected to the third output terminal of the driving circuit 210.

[0099] For example, continuing to refer to Figure 7 The enable terminals of the analog switches 221 can be connected to the enable control terminal OUT1 of the driving circuit 210. By outputting different levels of enable signals through the enable control terminal OUT1, the first transceiving circuit 250 or the second transceiving circuit 260 is controlled to be turned on, respectively.

[0100] For example, continuing to refer to Figure 8 The output terminal OE EN is an output terminal of the driving circuit 210, which can select the first output terminal or the second output terminal of the analog switch 221 by outputting a high level or a low level. For example, when the output terminal OE EN outputs a high level, the output terminal NO of the analog switch 221 is turned on at this time, and the transmission branch corresponding to the first ultrasonic transducer X1 is connected, and the receiving branch corresponding to the second ultrasonic transducer X2 is connected. Similarly, when the output terminal OE EN outputs a low level, the transmission branch corresponding to the second ultrasonic transducer X2 is connected, and the receiving branch corresponding to the first ultrasonic transducer X1 is connected.

[0101] In the embodiment, the switching of the two-way transceiving circuit 220 can be realized by connecting one enable output terminal, the circuit structure is simpler, the control mode is easier to realize, the resource occupation is less, and the expansibility is strong.

[0102] Optionally, each transmission branch and receiving branch includes a plurality of analog switches 221 connected in series.

[0103] If the transmission branch includes a plurality of analog switches 221 connected in series, the plurality of analog switches 221 are connected to the driving circuit 210 and the ultrasonic transducer 110 connected to the driving circuit 210, respectively. If the receiving branch includes a plurality of analog switches 221 connected in series, the plurality of analog switches 221 are connected to the bleeding circuit 240, the signal processing circuit 230, and the corresponding ultrasonic transducer 110, respectively.

[0104] When there are a plurality of analog switches 221 connected in series, and the analog switch 221 is a single-pole double-throw switch, the suspended output terminal of the analog switch 221 at the rear end can be grounded, so that the electrical signal generated by channel crosstalk on the unconnected channel is released. It should be noted that the first analog switch 221 on the transmission branch and the receiving branch along the direction of signal (excitation signal or echo signal) propagation cannot be connected to the channel of the rear-end analog switch 221 to avoid interfering with the excitation signal and the echo signal.

[0105] For example, Figure 9 A circuit structure diagram of an ultrasonic signal switching circuit with six analog switches provided by the embodiment of the present application. As shown in Figure 9As shown, each transmitting branch includes 2 analog switches 221, and each receiving branch includes 1 analog switch 221. Among them, chip U1, chip U2, capacitor C1, capacitor C2, chip U7, capacitor C7 constitute a first transceiver circuit 250, and the output end NO connected by chip U1, chip U2 and chip U7; chip U5, chip U6, capacitor C5, capacitor C6, chip U3, capacitor C3 constitute a second transceiver circuit 260, and the output end NC connected by chip U5, chip U6 and chip U3. When the output end OE_EN is high, the first transceiver circuit 250 is turned on, and the second transceiver circuit 260 is turned off.

[0106] Exemplarily, Figure 10 Another structure diagram of an ultrasonic signal switching circuit with 6 analog switches provided by an embodiment of the present application is shown in FIG. 6. Figure 10 As shown, each transmitting branch includes 1 analog switch 221, and each receiving branch includes 2 analog switches 221. The specific connection mode is similar to that of the embodiment shown in FIG. 5, and will not be described here. Figure 9

[0107] Exemplarily, Figure 11 A structure diagram of an ultrasonic signal switching circuit with 8 analog switches provided by an embodiment of the present application is shown in FIG. 7. Figure 11 As shown, each transmitting branch and each receiving branch includes 2 analog switches 221.

[0108] In an example, when the transmitting branch or the receiving branch is composed of 2 serially connected analog switches 221, the output end of the rear-end analog switch 221 which is not connected can be grounded. For example, Figure 9 to Figure 11 Among them, the output end NC of chip U2 and the output end NO of chip U6 are grounded; the output end NO of chip U4 and the output end NC of chip U8 are grounded. When there is a signal from channel crosstalk on the output end NC of chip U2, the output end NO of chip U6, the output end NO of chip U4 and the output end NC of chip U8, the signal can be discharged to the ground.

[0109] In the embodiment, by setting multiple serially connected analog switches 221 on each branch, channel crosstalk can be further reduced, and the signal-to-noise ratio of the echo signal can be increased. Meanwhile, multiple combination modes are listed, and the transmitting and receiving branches of each mode are independent, and there is no transceiver multiplexing, which can effectively reduce channel crosstalk. In actual application, the combination mode can be flexibly selected according to the scene, and the applicability and flexibility of the ultrasonic signal switching circuit are improved.

[0110] Optionally, the signal processing circuit 230 includes a first capacitor, a voltage bias unit and an amplifier; the echo signal input into the signal processing circuit 230 is pulled up to a positive potential level by the voltage bias unit after passing through the first capacitor.

[0111] ​The amplifier is an electronic component for amplifying an input signal, which can be an operational amplifier. Preferably, a controllable operational amplifier is enabled to reduce power consumption. The voltage biasing unit is a circuit for setting the operating point of the circuit. The voltage biasing unit modulates the echo signal by outputting a bias voltage, and pulls up the reference level of the echo signal. The positive potential level is the voltage value of the signal relative to the ground.

[0112] The specific implementation of the voltage biasing unit outputting a bias voltage can be through a resistance voltage dividing circuit, can output a bias voltage with an arbitrary voltage value through an analog output terminal of the master chip, or can provide a stable bias voltage through a voltage reference chip.

[0113] For example, continuing to refer to the signal processing circuit 230 in Figure 5 , which is composed of a first capacitor C10, a voltage biasing unit, an amplifier OPA and its peripheral circuit, and a filter circuit, and can amplify and filter the echo signal output by the amplifier OPA. Among them, the network MCU_OPA_EN is the enable terminal of the amplifier; the amplification circuit uses a positive feedback amplification circuit, and the amplification factor of the amplification circuit is A; the first capacitor C10 is a DC blocking capacitor, which is also a high-pass filter; the resistance R13 and the capacitor C16 constitute a passive low-pass filter circuit, and the cutoff frequency is f; the capacitor C13 is a DC blocking capacitor, which makes the output signal have no DC component.

[0114] The echo signal output by the receiving branch is input to the input terminal of the amplifier through the capacitor C10, wherein the capacitor C10 is a DC blocking capacitor, which filters out the DC component of the echo signal to filter out low-frequency noise and interference, that is, the echo signal input to the amplifier is a signal oscillating around 0 level. Since the amplifier will have obvious distortion when amplifying at zero crossing, the echo signal input to the amplifier can be modulated so that it is superimposed with the bias voltage output by the voltage biasing unit, so that the echo signal input to the amplifier is a positive potential level.

[0115] In some embodiments, the voltage biasing unit includes a first resistor, a second resistor, a third resistor, and a second capacitor; a first end of the first resistor is connected to a voltage source, a second end of the first resistor is connected to a first end of the second resistor and a first end of the third resistor respectively, a second end of the second resistor is grounded, a second end of the third resistor is connected to an input terminal of the amplifier; and the first capacitor is connected in parallel with the third resistor.

[0116] For example, continuing to refer to Figure 5The circuit consists of three resistors: R9 (first resistor), R8 (second resistor), R7 (third resistor), and C11 (second capacitor). Resistors R9 and R8 are connected in series between the voltage source VCC_RX and ground. By adjusting the values ​​of R9 and R8, the bias voltage output at the junction of the first and second resistors can be controlled. This bias voltage is then output to the amplifier's input through resistor R7. Resistor R7 acts as a current-limiting resistor, limiting the output bias voltage to prevent damage to the circuit from excessive bias. Capacitor C11 is a filter capacitor to reduce the noise of the bias voltage from interfering with the echo signal.

[0117] The voltage bias unit also includes a bypass capacitor C12 connected between the voltage source VCC_RX and the low voltage, which is used to stabilize the voltage source VCC_RX and reduce the power supply noise of the voltage source VCC_RX.

[0118] To match the voltage bias circuit and optimize the efficiency of the ultrasonic signal switching circuit, a front-end matching circuit needs to be added. (Continue referring to...) Figure 8 A front-end matching circuit is added between the excitation signal output terminal of the drive circuit 210 and the transceiver circuit 220. Figure 8 The circuit consists of resistors R1, R2, R3, R4, R5, capacitors C8 and C9. Resistor R1 corresponds to resistor R6 to ensure optimal matching of the ultrasonic transducer 110; its resistance is typically less than or equal to 1 kΩ. Resistor R2 is a pull-down resistor, preventing the ultrasonic transducer 110 from being excited when the drive circuit 210 does not send an excitation signal.

[0119] In this embodiment, by adding a voltage bias unit at the front end of the amplifier, the echo signal passing through the first capacitor is modulated, ensuring that the echo signal input to the amplifier is a positive potential signal. This avoids signal distortion, such as zero-crossing distortion, that would occur when the amplifier amplifies a negative potential signal. This improves the quality of the output signal of the signal processing circuit 230 and further enhances the accuracy of fluid measurement. Furthermore, the voltage bias unit is implemented using a resistor divider circuit, which is simple in structure, low in cost, and does not occupy excessive board space.

[0120] This application also provides an ultrasonic meter, including an ultrasonic transducer and the ultrasonic signal switching circuit provided in the above embodiments.

[0121] The ultrasonic meter provided in this application can be used in scenarios such as fluid metering, such as water meters and gas meters.

[0122] The number of ultrasonic transducers 110 included in the ultrasonic transducer can be 2, 4, etc. The layout of the ultrasonic transducers 110 in the ultrasonic transducer is determined according to the actual application scenario of the ultrasonic transducer, such as through-beam distribution, V-shaped distribution, or W-shaped distribution.

[0123] For example, Figure 12 This is a schematic diagram of the structure of an ultrasonic meter provided in an embodiment of this application. Figure 12 As shown, taking two ultrasonic transducers 110 as an example, the ultrasonic meter includes ultrasonic transducers 110, an ultrasonic signal switching circuit 200, a housing 300, a pipe 400, and a screen 500. The ultrasonic transducers 110 are located inside the pipe, and the two transducers 110 are arranged in a counter-beam configuration for transmitting and receiving ultrasonic waves within the pipe. The ultrasonic signal switching circuit 200 is located inside the housing 300 of the ultrasonic meter to control the ultrasonic transducers 110 and receive echo signals, enabling flow rate statistics through echo signal analysis. The pipe 400 is connected to the pipe containing the fluid to be tested, allowing the fluid to pass through the pipe 400. Figure 12 The fluid flows through pipe 400 in a wavy direction.

[0124] See also Figure 12 The ultrasonic meter also includes a screen 500, located on the surface of the housing 300, such as the side or top surface, for displaying measurement results, time, alarm information, and other information.

[0125] In one example, the ultrasonic meter also includes a communication module to send measurement results to remote devices, such as servers or client terminals.

[0126] In this embodiment, by using the ultrasonic signal switching circuit provided in the above embodiment, the channel crosstalk problem in the circuit during fluid measurement by the ultrasonic meter can be reduced, thereby improving the accuracy of fluid measurement.

[0127] In addition to fluid measurement, the ultrasonic signal switching circuit provided in this application can also be used in fluid detection, full-duplex communication, and other applications, in scenarios other than the ultrasonic meter provided in this application.

[0128] For example, different fluids have different effects on the propagation speed and attenuation of ultrasound. By analyzing ultrasound signals from different propagation directions, fluid properties such as cost and concentration can be inferred.

[0129] In the description of the disclosure, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the disclosure. In the description of the disclosure, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in one or more embodiments or examples.

[0130] In the description of the embodiments of the present application, it should be understood that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection" should be interpreted in a broad sense, for example, can be fixedly connected, can be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. The terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0131] The terms "first", "second", "third", "fourth" and the like in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to the process, method, product or device.

[0132] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e. can be located in one place, or can be distributed to multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiment according to actual needs.

[0133] It should be understood that many variations can be made in the embodiments described and shown which should be considered within the scope of the present application. In particular, it is to be understood that while the use of the first and second electrode materials described herein are preferred, other electrode materials can be used. It is also to be understood that while the use of the first and second electrolyte materials described herein are preferred, other electrolyte materials can be used. It is also to be understood that while the use of the first and second separators described herein are preferred, other separators can be used. It is also to be understood that while the use of the first and second binders described herein are preferred, other binders can be used. It is also to be understood that while the use of the first and second solvents described herein are preferred, other solvents can be used. It is also to be understood that while the use of the first and second conductive additives described herein are preferred, other conductive additives can be used. It is also to be understood that while the use of the first and second lithium ion sources described herein are preferred, other lithium ion sources can be used. It is also to be understood that while the use of the first and second lithium ion sources described herein are preferred, other lithium ion sources can be used. It is also to be understood that while the use of the first and second lithium ion sources described herein are preferred, other lithium ion sources can be used. It

Claims

1. An ultrasonic signal switching circuit, characterized in that, It includes a driver circuit, two transceiver circuits, a signal processing circuit, and a bleeder circuit; among which, Each of the transceiver circuits includes a pair of transmitting branches and receiving branches, respectively used to transmit the excitation signal output by the drive circuit to the connected ultrasonic transducer, and to receive the echo signal from the connected ultrasonic transducer; each of the transmitting branches and the receiving branches includes at least one analog switch; The input terminals of the bleeder circuit and the signal processing circuit are both connected to each of the receiving branches, and the output terminal of the bleeder circuit is grounded. The driving circuit is used to output enable signals to one of the transceiver circuits, the signal processing circuit, and the discharge circuit, respectively.

2. The circuit according to claim 1, characterized in that, The discharge circuit includes an analog switch; the enable terminal of the analog switch of the discharge circuit and the enable terminal of the signal processing circuit are respectively connected to the first output terminal and the second output terminal of the driving circuit.

3. The circuit according to claim 1, characterized in that, The bleeder circuit includes an analog switch; the enable terminal of the analog switch of the bleeder circuit is connected to the first output terminal of the drive circuit, and the first output terminal of the drive circuit is connected to the enable terminal of the signal processing circuit through an inverter.

4. The circuit according to claim 1, characterized in that, The analog switch is a single-pole double-throw switch.

5. The circuit according to claim 4, characterized in that, The two transceiver circuits include a first transceiver circuit and a second transceiver circuit; the analog switch in the transmitting branch includes an input terminal, a first output terminal, and a second output terminal. The input terminal of the analog switch in the transmitting branch of the first transceiver circuit is connected to the excitation signal output terminal of the driving circuit, the first output terminal is connected to the input terminal of the ultrasonic transducer or the next analog switch connected in series, and the second output terminal is left floating. The input terminal of the analog switch in the transmitting branch of the second transceiver circuit is connected to the excitation signal output terminal of the driving circuit, the second output terminal is connected to the input terminal of the ultrasonic transducer or the next analog switch connected in series, and the first output terminal is left floating.

6. The circuit according to claim 5, characterized in that, The enable terminals of the analog switches in both the receiving branch and the transmitting branch are connected to the third output terminal of the driving circuit.

7. The circuit according to claim 1, characterized in that, Each of the transmitting branch and the receiving branch includes a plurality of analog switches connected in series.

8. The circuit according to any one of claims 1-7, characterized in that, The signal processing circuit includes a first capacitor, a voltage biasing unit, and an amplifier; The echo signal input to the signal processing circuit is pulled up to a positive potential level by the voltage bias unit after passing through the first capacitor.

9. The circuit according to claim 8, characterized in that, The voltage biasing unit includes a first resistor, a second resistor, a third resistor, and a second capacitor; The first terminal of the first resistor is connected to a voltage source, the second terminal of the first resistor is connected to the first terminal of the second resistor and the first terminal of the third resistor, the second terminal of the second resistor is grounded, and the second terminal of the third resistor is connected to the input terminal of the amplifier; the first capacitor is connected in parallel with the third resistor.

10. An ultrasonic meter, characterized in that, It includes an ultrasonic transducer and an ultrasonic signal switching circuit according to any one of claims 1-9.

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