Ultrasonic transducer signal transmitting and receiving switching circuit

Abstract

The invention discloses an ultrasonic transducer signal transmitting and receiving switching circuit, which comprises a signal transmitting module, an ultrasonic sensor A, an ultrasonic sensor B and a signal receiving module, and is characterized in that the ultrasonic sensor A is electrically connected with the signal transmitting module through a first analog switch group and a third analog switch group; the ultrasonic sensor B is electrically connected with the signal transmitting module through a second analog switch group and a fourth analog switch group; the ultrasonic sensor A is electrically connected with the signal receiving module through the first analog switch group and the fifth analog switch group, and the ultrasonic sensor B is electrically connected with the signal receiving module through the second analog switch group and the sixth analog switch group. The receiving and transmitting switching circuit suppresses the problem of receiving channel coupling in a manner of consuming an interference signal coupled by an analog switch through grounding.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic measurement, and in particular to an ultrasonic transducer signal receiving and transmitting switching circuit. Background Art

[0002] The use of ultrasound to measure flow has the advantages of wide range, high accuracy, and maintenance-free. The time difference method is a typical ultrasonic flow measurement method. The average flow velocity of the fluid is calculated by measuring the time for the sound wave to propagate downstream and upstream in the flowing medium through circuit measurement, and then multiplied by the cross-sectional area of ​​the flow channel to obtain the flow rate of the fluid. The time difference method flow measurement circuit is generally composed of a controller, a pulse generator, a driver, a switching switch, a transducer, a transceiver switching circuit, an amplifier, a comparator, a timing unit, and a processor, such as Figure 1 Because the transmission time in both the downstream and upstream directions needs to be measured, the two transducers are used to transmit ultrasonic pulses and receive pulses, so a transceiver switching circuit is required to realize the transceiver switching during downstream and upstream measurements.

[0003] Conventional transmit / receive switching circuits use analog switches to switch transmit / receive states, such as Figure 2 As shown, the common ends of the two single-pole double-throw analog switches are respectively connected to the two transducers, the normally closed end of switch S7 and the normally open end of S8 are connected to the transmitting signal Fire of the driver, and the normally open end of S7 and the normally closed end of S8 are connected to the input signal Receive of the amplifier. Figure 2 In the state shown, the signal is sent from the U3 transducer, and U4 is in the receiving state. When it is necessary to measure in the reverse direction, the direction signal Dir is controlled at the same time to switch the switch to the normally closed end. Although this circuit can realize forward and reverse current transmission and reception switching, because the analog switch is not an ideal switch, there are problems of shutoff isolation and crosstalk, which causes the transmission signal to couple to the receiving channel, and even affects the recognition of normal signals when the operating frequency is high and the signal is weak. The improved design of the conventional transceiver switching circuit, such as ZL201822158329.7, reduces crosstalk to a certain extent, but there is still a certain degree of crosstalk when the signal is weak. Summary of the invention

[0004] The content of the invention introduces a series of simplified concepts, which will be further described in detail in the detailed description. The content of the invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0005] In order to at least partially solve the above problems, the present invention proposes an ultrasonic transducer signal transceiver switching circuit, the transceiver switching circuit includes a signal transmitting module, an ultrasonic sensor A, an ultrasonic sensor B and a signal receiving module, and is characterized in that:

[0006] The ultrasonic sensor A is electrically connected to the signal transmitting module through the first analog switch group and the third analog switch group, and the ultrasonic sensor B is electrically connected to the signal transmitting module through the second analog switch group and the fourth analog switch group;

[0007] The ultrasonic sensor A is electrically connected to the signal receiving module through the first analog switch group and the fifth analog switch group, and the ultrasonic sensor B is electrically connected to the signal receiving module through the second analog switch group and the sixth analog switch group.

[0008] Preferably, the fifth analog switch group and the sixth analog switch group are controlled by exclusive OR control of a direction switch and a receiving enable switch.

[0009] Preferably, the control mode of the first analog switch group, the second analog switch group, the third analog switch group and the fourth analog switch group is direction switch control.

[0010] Preferably, the fifth analog switch group and the sixth analog switch group are controlled by XOR control of a reverse direction switch and a receiving enable switch.

[0011] Preferably, the first analog switch group and the second analog switch group are controlled by an exclusive OR control of a direction switch and a receiving enable switch.

[0012] Preferably, the third analog switch group and the fourth analog switch group are controlled by direction switch control.

[0013] Preferably, the signal receiving module includes an amplifier, a comparator, a timing unit and a processor.

[0014] Preferably, the signal transmitting module includes a controller, a pulse generator and a driver.

[0015] Preferably, the other end of the ultrasonic sensor A or the ultrasonic sensor B is grounded.

[0016] Preferably, a normally closed end of the fourth analog switch group is grounded.

[0017] Preferably, a normally closed end of the sixth analog switch group is grounded.

[0018] Preferably, the first analog switch group, the second analog switch group, the third analog switch group, the fourth analog switch group, the fifth analog switch group and the sixth analog switch group each include one analog switch or two analog switches, and the analog switch is one of a single-channel single-pole double-throw analog switch chip, a multi-channel single-pole double-throw analog switch chip or an integrated chip.

[0019] Preferably, the two signal ends of the ultrasonic sensor A are electrically connected to the signal transmitting module through the first analog switch group and the third analog switch group, and the two signal ends of the ultrasonic sensor B are electrically connected to the signal transmitting module through the second analog switch group and the fourth analog switch group;

[0020] The two signal ends of the ultrasonic sensor A are electrically connected to the signal receiving module through the first analog switch group and the fifth analog switch group, and the two signal ends of the ultrasonic sensor B are electrically connected to the signal receiving module through the second analog switch group and the sixth analog switch group.

[0021] An ultrasonic metering module comprises the ultrasonic transducer signal receiving and transmitting switching circuit described above.

[0022] Beneficial effects of the present invention: The present invention proposes an ultrasonic transducer signal receiving and transmitting switching circuit, in which the forward and reverse current switching circuit uses 6 analog switch groups and adopts the measures of transmitting isolation grounding and receiving isolation grounding, which can effectively reduce the crosstalk effect of the transmitting channel on the receiving channel, and significantly improve the quality of the receiving signal near the transmitting signal. When the signal is weak and requires high-power amplification, the signal-to-noise ratio is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following drawings of the present invention are used to understand the present invention as part of the present invention. Embodiments of the present invention are shown in the drawings and the description thereof is used to explain the principle of the present invention.

[0024] In the attached figure:

[0025] Figure 1 It is a schematic diagram of a flow measurement circuit using a time difference method in the background technology of the present invention;

[0026] Figure 2 It is a schematic diagram of a conventional transceiver switching circuit in the background technology of the present invention;

[0027] Figure 3 A schematic diagram of an ultrasonic transducer signal receiving and transmitting switching circuit provided in Embodiment 1 of the present invention;

[0028] Figure 4 It is a schematic diagram of an ultrasonic transducer signal receiving and transmitting switching circuit provided in the second embodiment of the present invention;

[0029] Figure 5 A schematic diagram of an ultrasonic transducer signal receiving and transmitting switching circuit provided in Embodiment 3 of the present invention;

[0030] Figure 6 A schematic diagram of an ultrasonic transducer signal receiving and transmitting switching circuit provided in Embodiment 4 of the present invention;

[0031] Figure 7 This is a comparison diagram of the received waveforms obtained at the receiving end by the conventional circuit and the patented circuit. DETAILED DESCRIPTION

[0032] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0033] In order to fully understand the present invention, a detailed description will be provided in the following description. Obviously, the implementation of the embodiments of the present invention is not limited to the specific details familiar to those skilled in the art. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other embodiments.

[0034] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of the features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0035] Ordinal numbers such as "first" and "second" cited in the present invention are merely identifications and do not have any other meanings, such as a specific order, etc. Moreover, for example, the term "first component" itself does not imply the existence of the "second component", and the term "second component" itself does not imply the existence of the "first component".

[0036] It should be noted that the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside" and similar expressions used in this document are for illustrative purposes only and are not limiting.

[0037] Now, exemplary embodiments according to the present invention will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art.

[0038] Embodiment 1

[0039] Figure 3A schematic diagram of an ultrasonic transducer signal receiving and transmitting switching circuit provided in Embodiment 1 of the present invention is provided. In this embodiment, the problem of receiving channel coupling is suppressed by dissipating the interference signal coupled by the analog switch through the ground.

[0040] An ultrasonic transducer signal transceiver switching circuit, the transceiver switching circuit includes a signal transmitting module, an ultrasonic sensor U1, an ultrasonic sensor U2 and a signal receiving module, the ultrasonic sensor U1 is electrically connected to the signal transmitting module through a first analog switch group and a third analog switch group, and the ultrasonic sensor U2 is electrically connected to the signal transmitting module through a second analog switch group and a fourth analog switch group; the ultrasonic sensor U1 is electrically connected to the signal receiving module through a first analog switch group and a fifth analog switch group, and the ultrasonic sensor U2 is electrically connected to the signal receiving module through a second analog switch group and a sixth analog switch group. The control mode of the first analog switch group, the second analog switch group, the third analog switch group and the fourth analog switch group is direction switch control. The control mode of the fifth analog switch group and the sixth analog switch group is direction switch and receive enable switch exclusive OR control.

[0041] The normally closed end of the fourth analog switch group is grounded. The normally closed end of the sixth analog switch group is grounded.

[0042] The signal receiving module includes an amplifier, a comparator, a timing unit and a processor, and the signal transmitting module includes a controller, a pulse generator and a driver.

[0043] like Figure 3 As shown, the ultrasonic transducer signal receiving and transmitting switching circuit provided by the present invention is composed of 6 single-pole double-throw analog switches. In the figure, terminal 1 is a normally closed terminal, terminal 2 is a common terminal, and terminal 3 is a normally open terminal. Normally closed and normally open are relative, and they can be interchanged.

[0044] S1 and S2 are two analog switches for switching between transmitting and receiving. The control mode is Dir direction switch control. The two common terminals are connected to two transducers respectively. The normally closed terminal 1 of S1 and the normally open terminal 3 of S2 are connected to the common terminal 2 of the transmitting analog switch S3 and the common terminal 2 of S4 respectively. The normally open terminal 3 of S1 and the normally closed terminal 1 of S2 are connected to the common terminal 2 of the receiving analog switch S5 and the common terminal 2 of S6 respectively.

[0045] S3 and S4 are two analog switches for emission isolation. The control mode is Dir direction switch control. The normally closed terminal 1 of S3 and the normally open terminal 3 of S4 are connected to the emission signal Fire, and the normally open terminal 3 of S3 and the normally closed terminal 1 of S4 are connected to GND.

[0046] S5 and S6 are two analog switches for receiving isolation. The control method is the XOR control of the Dir direction switch and the Rcv_En receiving enable switch. The normally closed terminal 1 of S5 and the normally open terminal 3 of S6 are connected to the receiving signal Receive, and the normally open terminal 3 of S5 and the normally closed terminal 1 of S6 are connected to GND.

[0047] The forward and reverse Dir direction switch control signal and the Rcv_En receiving enable switch signal are used to control the transmission and reception switching at the same time. The control ends of the four analog switches S1 / S2 / S3 / S4 are controlled by the Dir direction switch, and S5 / S6 are controlled by the XOR value of the Dir direction switch and the Rcv_En receiving enable switch. The specific control method is:

[0048]

[0049]

[0050] The transceiver switching circuit suppresses the problem of receiving channel coupling by consuming the interference signal coupled by the analog switch through grounding.

[0051] Figure 3 In the embodiment, transducer U1 is in the transmitting state and transducer U2 is in the receiving state.

[0052] (1) Fire is connected to the normally closed terminal 1 of S3 and the normally open terminal 3 of S4. When Fire is working, the normally open terminal 3 of S3 and the normally closed terminal 1 of S4 will inevitably have coupled interference signals. At this time, they are both grounded, so the interference is greatly attenuated. Even if a small amount of interference is transmitted to the normally open terminal 3 of S2, the interference coupled to the normally closed terminal 1 of S2 is negligible;

[0053] (2) Fire is connected to S1 via S3. During the transmission, the normally open terminal 3 of S1 will still couple strong interference. S1 is connected to S5 and connected to the receiving amplifier circuit. At this time, the interference can generally be effectively shielded by the time window and will not affect the reception.

[0054] (3) During the transmission, U2 in the receiving state is connected to S6 through S2, thereby achieving grounding. Even if there is interference in the transmitting circuit, it will not affect the receiving transducer;

[0055] (4) After the transmission is completed and a delay of a period of time t is reached, before the reception signal arrives, the Rcv_En reception enable switch signal is adjusted, and S5 / S6 is switched to the normally open terminal 3. At this time, the receiving transducer U2 is connected to the Receive terminal, ready to receive the sound wave signal;

[0056] Delay time t=L / C, L is the sound path between the two transducers, and C is the speed of sound propagation in the medium.

[0057] (5) When switching directions, Dir is reversed, U2 acts as a transmitter, and U1 acts as a receiver. The above-mentioned mechanism of grounding to consume interference signals still holds true.

[0058]

[0059] Embodiment 2

[0060] Figure 4 A schematic diagram of an ultrasonic transducer signal transceiver switching circuit provided in Embodiment 2 of the present invention, the transceiver switching circuit includes a signal transmitting module, an ultrasonic sensor U1, an ultrasonic sensor U2 and a signal receiving module, the ultrasonic sensor U1 is electrically connected to the signal transmitting module through a first analog switch group and a third analog switch group, and the ultrasonic sensor U2 is electrically connected to the signal transmitting module through a second analog switch group and a fourth analog switch group; the ultrasonic sensor U1 is electrically connected to the signal receiving module through a first analog switch group and a fifth analog switch group, and the ultrasonic sensor U2 is electrically connected to the signal receiving module through a second analog switch group and a sixth analog switch group; the control mode of the fifth analog switch group and the sixth analog switch group is an XOR control of a reverse direction switch and a receiving enable switch; the control mode of the first analog switch group and the second analog switch group is an XOR control of a direction switch and a receiving enable switch; the control mode of the third analog switch group and the fourth analog switch group is a direction switch control.

[0061] The flow measurement circuit needs to measure the propagation time of the sound wave from one transducer to another transducer, and needs to set it to the transmitting and receiving states respectively. In the distance measurement application, it is necessary to measure the propagation time of the sound wave returning to the original transmitting transducer after reflection, and it is required to switch the transmitting and receiving states of a certain transducer in time-sharing, that is, to realize the self-transmitting and self-receiving function. The distance measurement mode can also be realized by using the switching circuit of the present invention, and the specific implementation method is as follows: Figure 4 shown.

[0062] The ultrasonic transducer signal receiving and transmitting switching circuit provided by the present invention is composed of 6 single-pole double-throw analog switches. In the figure, terminal 1 is a normally closed terminal, terminal 2 is a common terminal, and terminal 3 is a normally open terminal. Normally closed and normally open are relative, and interchange is also valid.

[0063] On the basis of the first embodiment, the control end of the S1 / S2 analog switch is adjusted to the XOR value of Dir and Rcv_En for control, and the control end of S5 / S6 is adjusted to the value of Dir inverted and then XORed with Rcv_En for control, and the control end of S3 / S4 remains unchanged, so that the self-transmitting and self-receiving function can be realized. Similar to the principle of the first embodiment, when transmitting with U1, S1 / S2 is in the normally closed end, U1 is in the transmitting state, S5 / S6 is in the normally open end, and U2 is in the receiving state; before the receiving signal arrives, the Rcv_En signal is enabled, S1 / S2 is switched to the normally open end, S5 / S6 is switched to the normally closed end, at this time U1 is in the receiving state, and U2 is in the grounding state, thereby realizing the self-transmitting and self-receiving of U1. Setting Dir high can switch U2 for self-transmitting and self-receiving. Although this embodiment does not design U1 to be grounded during the non-transmitting and receiving time separately, since the driving circuit itself has a grounding effect when the transmitting signal ends, this embodiment still has a strong suppression effect on the residual vibration of the transmitting signal.

[0064] S1 and S2 are two analog switches for switching between transmitting and receiving. The control mode is Dir direction switch and Rcv_En receiving enable switch control. The two common terminals are connected to the two transducers U1 and U2 respectively. The normally closed terminal 1 of S1 and the normally open terminal 3 of S2 are connected to the common terminal 2 of the transmitting analog switch S3 and the common terminal 2 of S4 respectively. The normally open terminal 3 of S1 and the normally closed terminal 1 of S2 are connected to the common terminal 2 of the receiving analog switch S5 and the common terminal 2 of S6 respectively.

[0065] S3 and S4 are two analog switches for emission isolation. The control mode is Dir direction switch control. The normally closed terminal 1 of S3 and the normally open terminal 3 of S4 are connected to the emission signal Fire, and the normally open terminal 3 of S3 and the normally closed terminal 1 of S4 are connected to GND.

[0066] S5 and S6 are two analog switches for receiving isolation. The control method is the exclusive OR control of the NOT (Dir) reverse direction switch and the Rcv_En receiving enable switch. The normally closed terminal 1 of S5 and the normally open terminal 3 of S6 are connected to the receiving signal Receive, and the normally open terminal 3 of S5 and the normally closed terminal 1 of S6 are connected to GND.

[0067] The forward and reverse Dir direction switch control signal and the Rcv_En receiving enable switch signal are used to simultaneously control the sending and receiving switching. The control ends of the two analog switches S3 / S4 are controlled by the Dir direction switch, S1 / S2 are controlled by the XOR value of the Dir direction switch and the Rcv_En receiving enable switch, and S5 / S6 are controlled by the XOR value of the NOT (Dir) reverse direction switch and the Rcv_En receiving enable switch. The specific control method is:

[0068]

[0069]

[0070] Figure 4 In the embodiment, transducer U1 is in the transmitting state and transducer U2 is in the receiving state.

[0071] (1) Fire transmits the driving signal emitted by the signal transmission module to the transducer U1 through the normally closed terminal 1 of S3 and the normally closed terminal 1 of S1. The transducer U1 is stimulated to emit an ultrasonic signal. In this process, the normally open terminal 3 of S3 will be interfered with. At the same time, the normally open terminal 3 of S4 may transmit the driving signal to the normally closed terminal 1 of S4. The normally closed terminal 1 of S4 and the normally open terminal 3 of S3 are grounded to reduce the interference signal. Even if the normally open terminal 3 of S4 transmits the interference signal to the normally open terminal 3 of S2, the normally open terminal 3 of S2 is suspended at this time, and the interference signal will also decrease.

[0072] (2) During the transmission, U2 in the receiving state is connected to S6 through S2, thereby achieving grounding. Even if there is interference in the transmitting circuit, it will not affect the receiving transducer;

[0073] (3) After the transmission is completed and a delay of a period of time t is reached, before the reception signal arrives, the Rcv_En reception enable switch signal is adjusted, and S5 / S6 is switched to the normally open terminal 3. At this time, the receiving transducer U2 is connected to the Receive terminal, ready to receive the sound wave signal;

[0074] Delay time t=L / C, L is the sound path between the two transducers, and C is the speed of sound propagation in the medium.

[0075] (4) When switching directions, Dir is reversed, U2 acts as a transmitter, and U1 acts as a receiver. The above-mentioned mechanism of grounding to consume interference signals still holds true;

[0076] (5) It can be seen from the above specific control methods that both the transducer U1 and U2 can realize the function of sending and receiving ultrasonic signals by themselves, that is, the ranging function.

[0077] Embodiment 3

[0078] Figure 5 The schematic diagram of an ultrasonic transducer signal transceiver switching circuit provided in the third embodiment of the present invention includes a signal transmitting module, an ultrasonic sensor transducer 11, an ultrasonic sensor transducer 12 and a signal receiving module.

[0079] The ultrasonic sensor transducer 11 is electrically connected to the signal transmitting module through the first analog switch group and the third analog switch group, and the ultrasonic sensor transducer 12 is electrically connected to the signal transmitting module through the second analog switch group and the fourth analog switch group;

[0080] The ultrasonic sensor transducer 11 is electrically connected to the signal receiving module through the first analog switch group and the fifth analog switch group, and the ultrasonic sensor transducer 12 is electrically connected to the signal receiving module through the second analog switch group and the sixth analog switch group.

[0081] The first analog switch group, the second analog switch group, the third analog switch group, the fourth analog switch group, the fifth analog switch group and the sixth analog switch group each include one analog switch or two analog switches, and the analog switch is one of a single-channel single-pole double-throw analog switch chip, a multi-channel single-pole double-throw analog switch chip or an integrated chip.

[0082] Figure 5 It is a single-ended transceiver switching circuit solution designed based on Example 1, wherein the first analog switch group, the second analog switch group, the third analog switch group, the fourth analog switch group, the fifth analog switch group and the sixth analog switch group each include an analog switch, namely S11, S12, S13, S14, S15 and S16, which are single-channel single-pole double-throw analog switch chips, and use the two signals Dir and Rcv_En to be connected to the receiving analog switch control terminal via an XOR gate chip.

[0083] Figure 5 In the figure, transducer 11 is in a transmitting state, one end of which is electrically connected to S11 and the other end is grounded; transducer 12 is in a receiving state, one end of which is electrically connected to S12 and the other end is grounded.

[0084] (1) Fire is connected to the normally closed end SB of S13 and the normally open end SA of S14. When Fire is working, S11 and S13 are at the normally closed end SB, and transducer 11 is in the transmitting state; the normally open end SA of S13 and the normally closed end SB of S14 will inevitably have coupled interference signals. At this time, their other ends are grounded, which will greatly attenuate the interference signals. Even if a small amount of interference is transmitted to the normally open end SA of S12, the normally open end SA of S12 is suspended at this time, so the interference coupled to the normally closed end SB of S12 is negligible;

[0085] (2) Fire is connected to S11 via S13. During the transmission, S11 is always open and SA will still couple strong interference. S11 is connected to S15 and connected to the receiving amplifier circuit. At this time, the interference can generally be effectively shielded by the time window and will not affect the reception.

[0086] (3) During the transmission, the transducer 12 in the receiving state is connected to S16 via S12, thereby achieving grounding. Even if there is interference in the transmitting circuit, it will not affect the receiving transducer;

[0087] (4) After the transmission is completed and a delay of a period of time t is applied, before the reception signal arrives, the Rcv_En signal is adjusted, and S15 / S16 is switched to the normally open end SA. At this time, the receiving transducer 12 is connected to the receiving end, and the ultrasonic wave emitted by the transducer 11 is received by the transducer 12 and then transmitted to the signal receiving module;

[0088] Delay time t=L / C, L is the sound path between the two transducers, and C is the speed of sound propagation in the medium.

[0089] Due to the delay for a period of time, the signal received by the transducer 12 is less affected by the interference signal.

[0090] (5) When switching directions, Dir is reversed, transducer 12 is used as a transmitter, and transducer 11 is used as a receiver. The above-mentioned mechanism of grounding to consume interference signals still holds true.

[0091] Embodiment 4

[0092] Figure 6 The schematic diagram of an ultrasonic transducer signal transceiver switching circuit provided in the fourth embodiment of the present invention includes a signal transmitting module, an ultrasonic sensor transducer 21, an ultrasonic sensor transducer 22 and a signal receiving module.

[0093] The two signal ends of the ultrasonic sensor transducer 21 are electrically connected to the signal transmitting module through the first analog switch group and the third analog switch group, and the two signal ends of the ultrasonic sensor transducer 22 are electrically connected to the signal transmitting module through the second analog switch group and the fourth analog switch group;

[0094] The two signal ends of the ultrasonic sensor Transducer 21 are electrically connected to the signal receiving module through the first analog switch group and the fifth analog switch group, and the two signal ends of the ultrasonic sensor B are electrically connected to the signal receiving module through the second analog switch group and the sixth analog switch group.

[0095] In this solution, the first analog switch group, the second analog switch group, the third analog switch group, the fourth analog switch group, the fifth analog switch group and the sixth analog switch group all include two analog switches. The analog switch uses a dual-channel analog switch chip, and can also be designed as a single-channel or four-channel chip or designed as a single-chip integrated circuit. The difference lies in the discreteness of different channels, but it does not affect the interference suppression effect of this solution.

[0096] Figure 6 This is the differential transceiver switching circuit solution proposed by the present invention. The difference is that the two signal ends of the transducer are respectively connected to their respective transceiver switching / transmit isolation / receive isolation analog switch groups, and the number of analog switches used is increased by 1 time, using 12 analog switches. The transmission signal is a differential excitation signal connected to two groups of transmission isolation switches respectively, and the signals received at both ends of the transducer are combined into a receiving differential signal by receiving two groups of isolation switches.

[0097] Figure 6 In the embodiment, transducer 21 is in a transmitting state, and both signal terminals are electrically connected to S21; transducer 22 is in a receiving state, and both signal terminals are electrically connected to S22.

[0098] (1) Fire is the superposition of two driving signals. After a brief signal analysis, it is connected to the two normally closed ends of S23 and the two normally open ends of S24. When Fire is working, S21 and S23 are at the normally closed ends, and transducer 21 transmits the superposition wave of the two signals. During this period, the normally open end of S23 and the normally closed end of S24 will inevitably have coupled interference signals. At this time, their other ends are grounded, which will greatly attenuate the interference signal. Even if a small amount of interference is transmitted to the normally open end of S22, the normally open end of S22 is suspended at this time, so the interference coupled to the normally closed end of S22 is negligible;

[0099] (2) Fire is connected to S21 via S23. During the transmission, S21 is always open and will still couple strong interference. S21 is connected to S25 and connected to the receiving amplifier circuit. At this time, the interference can generally be effectively shielded by the time window and will not affect the reception.

[0100] (3) During the transmission, the transducer 22 in the receiving state is connected to S26 via S22, thereby achieving grounding. Even if there is interference in the transmitting circuit, it will not affect the receiving transducer;

[0101] (4) After the transmission is completed and a delay period is set, before the reception signal arrives, the Rcv_En signal is adjusted, S25 / S26 is switched to the normally open ends S1B and S2B, and the receiving transducer 22 is connected to the Receive end. The ultrasonic wave emitted by the transducer 21 is received by the transducer 22 and transmitted to the signal receiving module;

[0102] Delay time t=L / C, L is the sound path between the two transducers, and C is the speed of sound propagation in the medium.

[0103] Due to the delay for a period of time, the signal received by the transducer 22 is less affected by the interference signal.

[0104] (5) When switching directions, Dir is reversed, transducer 22 is used as a transmitter, and transducer 21 is used as a receiver. The above-mentioned mechanism of grounding to consume interference signals still holds true.

[0105] (6) The circuit arrangements of Embodiments 1 to 3 can all be used in the differential circuit of Embodiment 4.

[0106] Embodiments 1 to 4 only list the operation modes of some operators of analog switches. The present invention is not limited to the implementation modes mentioned in the above embodiments. Any implementation modes with the same principle as the present invention are within the protection scope of the present invention.

[0107] Embodiment 5

[0108] The fifth embodiment of the present invention further provides an ultrasonic metering module, comprising the ultrasonic transducer signal receiving and transmitting switching circuit described in the first to fourth embodiments.

[0109] Figure 7 This is a comparison diagram of the received waveforms obtained at the receiving end by the conventional circuit and the patented circuit. It can be seen that after the patented waveform is amplified by a high magnification, there is less clutter and still maintains a good signal-to-noise ratio.

[0110] Through the above description of the implementation mode, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course it can also be implemented by hardware, but in many cases the former is a better implementation mode. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of various embodiments of the present invention.

[0111] It is worth noting that in the above-mentioned embodiment of the ultrasonic transducer signal receiving and transmitting switching circuit, the various units and modules included are only divided according to functional logic, but are not limited to the above-mentioned division, as long as the corresponding functions can be achieved; in addition, the specific names of the functional units are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.

[0112] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An ultrasonic transducer signal transceiver switching circuit, the transceiver switching circuit comprising a signal transmitting module, an ultrasonic sensor A, an ultrasonic sensor B and a signal receiving module, characterized in that: The ultrasonic sensor A is electrically connected to the signal transmitting module through the first analog switch group and the third analog switch group, and the ultrasonic sensor B is electrically connected to the signal transmitting module through the second analog switch group and the fourth analog switch group; The ultrasonic sensor A is electrically connected to the signal receiving module through the first analog switch group and the fifth analog switch group, and the ultrasonic sensor B is electrically connected to the signal receiving module through the second analog switch group and the sixth analog switch group.

2. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 1, characterized in that: The fifth analog switch group and the sixth analog switch group are controlled by an exclusive OR control of a direction switch and a receiving enable switch.

3. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 2, characterized in that: The control mode of the first analog switch group, the second analog switch group, the third analog switch group and the fourth analog switch group is direction switch control.

4. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 1, characterized in that: The fifth analog switch group and the sixth analog switch group are controlled by an exclusive OR control of a reverse direction switch and a receiving enable switch.

5. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 4, characterized in that: The control mode of the first analog switch group and the second analog switch group is XOR control of a direction switch and a receiving enable switch.

6. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 5, characterized in that: The control mode of the third analog switch group and the fourth analog switch group is direction switch control.

7. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 1, characterized in that: The signal receiving module includes an amplifier, a comparator, a timing unit and a processor.

8. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 1, characterized in that: The signal transmission module includes a controller, a pulse generator and a driver.

9. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 1, characterized in that: The other end of the ultrasonic sensor A or the ultrasonic sensor B is grounded.

10. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 1, characterized in that: The normally closed end of the fourth analog switch group is grounded.

11. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 1, characterized in that: The normally closed end of the sixth analog switch group is grounded.

12. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 1, characterized in that: The first analog switch group, the second analog switch group, the third analog switch group, the fourth analog switch group, the fifth analog switch group and the sixth analog switch group each include one analog switch or two analog switches, and the analog switch is one of a single-channel single-pole double-throw analog switch chip, a multi-channel single-pole double-throw analog switch chip or an integrated chip.

13. The ultrasonic transducer signal receiving and transmitting switching circuit according to claim 12, characterized in that: The two signal ends of the ultrasonic sensor A are electrically connected to the signal transmitting module through the first analog switch group and the third analog switch group, and the two signal ends of the ultrasonic sensor B are electrically connected to the signal transmitting module through the second analog switch group and the fourth analog switch group; The two signal ends of the ultrasonic sensor A are electrically connected to the signal receiving module through the first analog switch group and the fifth analog switch group, and the two signal ends of the ultrasonic sensor B are electrically connected to the signal receiving module through the second analog switch group and the sixth analog switch group.

14. An ultrasonic metering module, characterized in that: It comprises an ultrasonic transducer signal receiving and transmitting switching circuit as described in claims 1 to 13.

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