Signal conditioning circuit of modular tooth root apex locator

Abstract

The invention discloses a modular root apex locator signal conditioning circuit, which comprises a main controller, an excitation signal input port and a signal conditioning module, and is characterized in that the excitation signal input port is suitable for receiving a first excitation signal generated by the main controller; the signal conditioning module comprises a single-ended to differential circuit, an attenuation circuit and a root canal measurement output port; the single-ended to differential circuit is electrically connected with the excitation signal input port, and the single-ended to differential circuit is suitable for converting a first excitation signal input from the excitation signal input port into a differential form from a single-ended form so as to form a second excitation signal; the attenuation circuit is electrically connected with the single-ended to differential circuit, and the attenuation circuit is suitable for performing attenuation processing on the second excitation signal which is converted into the differential form so as to form a third excitation signal; the signal processing flow can be simplified, the consistency of measurement results is improved, and the maintenance cost is reduced through modular design.

Description

Technical Field

[0001] The invention relates to a modular tooth apex locator signal conditioning circuit, belonging to the technical field of signal processing circuits. Background Art

[0002] As a key device for measuring root canal length in dental treatment, the apex locator relies on the precise acquisition and analysis of bioimpedance signals. The current mainstream measurement method uses multi-frequency excitation to collect high- and low-frequency amplitudes, and uses the ratio of high- to low-frequency amplitudes as the measurement result. However, the traditional amplitude acquisition method has many disadvantages: The signal processing process is complicated, relying on multiple steps such as filtering, attenuation, amplification, and rectification. Finally, the ratio needs to be calculated by the main control controller, making the entire process cumbersome. The errors of components, especially capacitors, are large, which seriously affects the consistency of measurement results; The lack of modular design makes maintenance costs high and requires further reliance on software and hardware for further processing. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the existing technology and provide a modular tooth apex locator signal conditioning circuit, which can simplify the signal processing process, improve the consistency of measurement results, and reduce maintenance costs through modular design.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a modular tooth apex locator signal conditioning circuit, characterized by comprising: Main controller; an excitation signal input port, the excitation signal input port being adapted to receive a first excitation signal generated by the main controller; A signal conditioning module, comprising a single-ended to differential circuit, an attenuation circuit, and a root canal measurement output port; The single-ended to differential circuit is electrically connected to the excitation signal input port, and the single-ended to differential circuit is adapted to convert the first excitation signal input from the excitation signal input port from a single-ended form to a differential form to form a second excitation signal; an attenuation circuit, the attenuation circuit being electrically connected to the single-ended to differential conversion circuit, the attenuation circuit being adapted to perform attenuation processing on the second excitation signal converted into a differential form to form a third excitation signal; A root canal measurement output port is electrically connected to an external root canal to be measured, and the root canal measurement output port is suitable for outputting the third excitation signal to the external root canal to be measured.

[0005] Furthermore, in order to receive the response signal of the external root canal to be measured, the signal conditioning module also includes a root canal measurement input port, which is electrically connected to the external root canal to be measured and is suitable for receiving the response signal of the external root canal to be measured.

[0006] Furthermore, in order to improve the accuracy of signal processing, the signal conditioning module also includes a differential amplifier circuit, which is electrically connected to the root canal measurement port. The response signal of the external root canal to be measured is amplified by the differential amplifier circuit to form a measurement signal.

[0007] Furthermore, a modular root apex locator signal conditioning circuit also includes a sampling signal output port, which is electrically connected to the differential amplifier circuit, and the sampling signal output port is suitable for receiving the measurement signal and transmitting it to the main controller for digital signal processing.

[0008] Furthermore, the first excitation signal and the measurement signal are both sinusoidal or square wave signals.

[0009] After adopting the above technical solution, the present invention has the following beneficial effects: In the present invention, the main controller generates a single-ended first excitation signal (sine wave or square wave) and transmits it to the signal conditioning module through the excitation signal input port. The single-ended to differential circuit converts it into a differential second excitation signal to eliminate common-mode interference and improve signal transmission stability. The attenuation circuit attenuates the second excitation signal by -34dB±0.5dB to form a third excitation signal, significantly reducing the output current to ensure human safety. The response signal generated by the root canal after being stimulated is received by the root canal measurement input port. The differential amplifier circuit amplifies the weak response signal with a gain of 28dB±0.5dB to form a measurement signal, which is then transmitted back to the main controller through the sampling signal output port. The main controller performs analog-to-digital conversion and digital processing on the measurement signal, combines it with the characteristics of the excitation signal, calculates the impedance characteristics of the root canal, and accurately locates the root apex.

[0010] This modular apex locator signal conditioning circuit achieves the generation and conditioning of excitation signals and high-precision acquisition of response signals through modular design, simplifies the signal processing process and ensures safety. The modular design makes each functional unit independent and easy to maintain and upgrade. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a circuit schematic diagram of a modular tooth apex locator signal conditioning circuit of the present invention; Figure 2 A schematic flow chart of a modular tooth apex locator signal conditioning circuit according to the present invention; Figure 3 Schematic diagram of the processing flow of the main controller of the present invention. DETAILED DESCRIPTION

[0012] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0013] like Figure 1-3 , a modular tooth apex locator signal conditioning circuit, comprising: Main controller; an excitation signal input port, the excitation signal input port being adapted to receive a first excitation signal generated by a main controller; Signal conditioning module, the signal conditioning module includes a single-ended to differential circuit, an attenuation circuit and a root canal measurement output port; The single-ended to differential circuit is electrically connected to the excitation signal input port, and the single-ended to differential circuit is adapted to convert the first excitation signal input from the excitation signal input port from a single-ended form to a differential form to form a second excitation signal; an attenuation circuit, the attenuation circuit being electrically connected to the single-ended to differential conversion circuit, and the attenuation circuit being adapted to perform attenuation processing on the second excitation signal converted into a differential form to form a third excitation signal; The root canal measurement output port is electrically connected to an external root canal to be measured, and the root canal measurement output port is suitable for outputting the third excitation signal to the external root canal to be measured.

[0014] In this embodiment, the main controller is an MCU. Any single-chip microcomputer with an ARM Cortex-M series core can be used. In this embodiment, the one used is AT32F423.

[0015] like Figure 1 As shown, in this embodiment, the attenuation circuit includes a unidirectional attenuation network and a reverse attenuation network. The unidirectional attenuation network is provided with resistors R1, R3, R4, R5 and a first operational amplifier U1. The reverse attenuation network is provided with resistors R8, R10, R11, R12 and a second operational amplifier U2. The resistance values ​​of R1=R4=R8=R11, R3=R5=R10=R12 are equal. The first operational amplifier U1 and the second operational amplifier U2 are both conventional operational amplifier integrated chips.

[0016] Specifically, if Figure 1-2 As shown, the signal conditioning module further includes a root canal measurement input port, which is electrically connected to an external root canal to be measured and is suitable for receiving a response signal of the external root canal to be measured.

[0017] Specifically, if Figure 1-2As shown, the signal conditioning module further includes a differential amplifier circuit, which is electrically connected to the root canal measurement port. The response signal of the external root canal to be measured is amplified by the differential amplifier circuit to form a measurement signal.

[0018] In this embodiment, the differential amplifier circuit is provided with a resistor R7 and a third operational amplifier U3. The resistor R7 is suitable for adjusting the differential amplifier gain. The third operational amplifier U3 is an instrumentation amplifier integrated chip. The REF pin of the third operational amplifier U3 is grounded in order to set the reference voltage so that the amplified signal is adapted to the main controller signal acquisition.

[0019] Specifically, if Figure 1-2 As shown, a modular root apex locator signal conditioning circuit also includes a sampling signal output port, which is electrically connected to the differential amplifier circuit. The sampling signal output port is suitable for receiving the measurement signal and transmitting it to the main controller for digital signal processing.

[0020] Specifically, if Figure 1-3 As shown, the first excitation signal and the measurement signal are both sinusoidal or square wave signals.

[0021] Specifically, if Figure 3 As shown, the main controller in this embodiment conditions and samples the excitation signal, first improving the signal quality through the signal conditioning circuit, then sampling the high-frequency (Wh) and low-frequency (WL) signals, and then processing the signals using time division multiplexing technology to extract the amplitude and phase information of the high-frequency and low-frequency signals; Finally, the spectrum of the signal is analyzed by Fast Fourier Transform (FFT), and the ratio of the signal is calculated to facilitate further signal analysis and application.

[0022] In this embodiment, the attenuation coefficient of the attenuation circuit on the second excitation signal is -34dB±0.5dB.

[0023] The amplification gain of the differential amplifier circuit to the response signal of the external root canal to be tested is 28dB±0.5dB. The operator can modify the attenuation coefficient and the amplification gain by adjusting the resistance values ​​of the relevant resistors in this conditioning circuit according to actual needs.

[0024] In this embodiment, in the present invention, the main controller generates a first excitation signal (sine wave or square wave) in a single-ended form and transmits it to the signal conditioning module through the excitation signal input port. The single-ended to differential circuit converts it into a second excitation signal in a differential form, eliminating common-mode interference and improving signal transmission stability. The attenuation circuit attenuates the second excitation signal by -34dB±0.5dB to form a third excitation signal, significantly reducing the output current to ensure human safety. The response signal generated by the root canal after being stimulated is received by the root canal measurement input port. The differential amplifier circuit amplifies the weak response signal with a gain of 28dB±0.5dB to form a measurement signal, which is then transmitted back to the main controller through the sampling signal output port. The main controller performs analog-to-digital conversion and digital processing on the measurement signal, combines it with the characteristics of the excitation signal, calculates the impedance characteristics of the root canal, and accurately locates the root apex.

[0025] This modular apex locator signal conditioning circuit achieves the generation and conditioning of excitation signals and high-precision acquisition of response signals through modular design, simplifies the signal processing process and ensures safety. The modular design makes each functional unit independent and easy to maintain and upgrade.

[0026] The above specific embodiments further illustrate the technical problems, technical solutions and beneficial effects solved by the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A modular tooth apex locator signal conditioning circuit, characterized in that: include: Main controller; an excitation signal input port, the excitation signal input port being adapted to receive a first excitation signal generated by the main controller; A signal conditioning module, comprising a single-ended to differential circuit, an attenuation circuit, and a root canal measurement output port; The single-ended to differential circuit is electrically connected to the excitation signal input port, and the single-ended to differential circuit is adapted to convert the first excitation signal input from the excitation signal input port from a single-ended form to a differential form to form a second excitation signal; an attenuation circuit, the attenuation circuit being electrically connected to the single-ended to differential conversion circuit, the attenuation circuit being adapted to perform attenuation processing on the second excitation signal converted into a differential form to form a third excitation signal; A root canal measurement output port is electrically connected to an external root canal to be measured, and the root canal measurement output port is suitable for outputting the third excitation signal to the external root canal to be measured.

2. The modular tooth apex locator signal conditioning circuit according to claim 1, characterized in that: The signal conditioning module further includes a root canal measurement input port, which is electrically connected to an external root canal to be measured and is suitable for receiving a response signal of the external root canal to be measured.

3. The modular tooth apex locator signal conditioning circuit according to claim 2, characterized in that: The signal conditioning module further includes a differential amplifier circuit, which is electrically connected to the root canal measurement port. The response signal of the external root canal to be measured is amplified by the differential amplifier circuit to form a measurement signal.

4. The modular tooth apex locator signal conditioning circuit according to claim 3, characterized in that: It also includes a sampling signal output port, which is electrically connected to the differential amplifier circuit and is suitable for receiving the measurement signal and transmitting it to the main controller for digital signal processing.

5. The modular tooth apex locator signal conditioning circuit according to claim 1, characterized in that: The first excitation signal and the measurement signal are both sinusoidal or square wave signals.

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