Adaptive control method, device, circuit, equipment and medium of bias voltage

Abstract

The application relates to the technical field of electronic technology, and discloses an adaptive control method, device, circuit, equipment and medium for a bias voltage. The method comprises the following steps: acquiring comprehensive noise of a diode unit, the diode unit comprising an avalanche photodiode and an operational amplifier circuit; acquiring a change trend of the comprehensive noise, and judging whether the avalanche photodiode reaches saturation output based on the change trend; when the avalanche photodiode reaches saturation output, acquiring a minimum bias voltage of the avalanche photodiode; adjusting the bias voltage of the avalanche photodiode based on the minimum bias voltage by using a dichotomy method, and acquiring real-time output of the avalanche photodiode during the adjustment; and when the real-time output is within a target output range, acquiring a target working voltage of a time domain reflectometer according to the bias voltage corresponding to the real-time output within the target output range. The application can effectively improve the efficiency and accuracy of determining the target working voltage, and reduce the instability of the OTDR.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to adaptive control methods, devices, circuits, equipment, and media for bias voltage. Background Technology

[0002] An OTDR (Optical Time Domain Reflectometer) is an instrument used to measure parameters such as attenuation, loss, and reflection in optical fiber links. It analyzes the performance of the fiber optic link by sending pulsed optical signals into the fiber and then measuring the reflection and scattering of the light signals. An Avalanche Photodiode (APD) is a key component of the OTDR, used to receive and amplify the reflected optical signals.

[0003] Traditional APD bias control methods mainly involve placing a thermistor near the APD device and establishing a linear relationship between the APD bias voltage and the ambient temperature through the feedback of the thermistor, thus performing bias compensation. This approach is rather crude, resulting in an inaccurate bias voltage and unstable OTDR dynamic range. Furthermore, this approach requires calibration compensation at high and low temperatures, which is cumbersome and inefficient. Summary of the Invention

[0004] Therefore, it is necessary to propose an adaptive control method, device, circuit, equipment, and medium for bias voltage to address the above problems. This can improve the efficiency and accuracy of determining the target operating voltage and enhance the stability of the time domain reflectometer.

[0005] An adaptive control method for bias voltage is provided for controlling the bias voltage of a time domain reflectometer, wherein the detector portion of the time domain reflectometer uses an avalanche photodiode.

[0006] The adaptive control method for the bias voltage includes the following steps:

[0007] The overall noise of the diode unit is obtained, wherein the diode unit includes the avalanche photodiode and an operational amplifier circuit;

[0008] Obtain the trend of the overall noise, and determine whether the avalanche photodiode has reached saturation output based on the trend.

[0009] When the avalanche photodiode reaches saturation output, the minimum bias voltage of the avalanche photodiode is obtained;

[0010] The bias voltage of the avalanche photodiode is adjusted using a binary method based on the minimum bias voltage. While adjusting, the real-time output of the avalanche photodiode is obtained. When the real-time output is within the target output range, the target operating voltage of the time domain reflectometer is obtained according to the bias voltage corresponding to the real-time output within the target output range.

[0011] An adaptive control device for bias voltage is provided for controlling the operating voltage of a time domain reflectometer, wherein the detector portion of the time domain reflectometer uses an avalanche photodiode.

[0012] The adaptive control device for the bias voltage includes the following modules:

[0013] A noise module is used to acquire the combined noise of the diode unit when the laser of the time domain reflectometer is turned off, the diode unit including the avalanche photodiode and an operational amplifier circuit;

[0014] The judgment module is used to obtain the changing trend of the comprehensive noise and determine whether the avalanche photodiode has reached saturation output based on the changing trend;

[0015] A voltage module is used to obtain the minimum bias voltage of the avalanche photodiode when the avalanche photodiode reaches saturation output.

[0016] The adjustment module is used to adjust the bias voltage of the avalanche photodiode using a binary method based on the minimum bias voltage. While adjusting, it acquires the real-time output of the avalanche photodiode. When the real-time output is within the target output range, it acquires the target operating voltage of the time domain reflectometer based on the bias voltage corresponding to the real-time output within the target output range.

[0017] An adaptive control circuit for bias voltage is provided to implement the adaptive control method for bias voltage as described above.

[0018] The adaptive control circuit for the bias voltage includes:

[0019] An analog-to-digital converter circuit, connected to an operational amplifier circuit and an avalanche photodiode, is used to obtain the real-time output of the avalanche photodiode and the combined noise of the avalanche photodiode and the operational amplifier circuit;

[0020] The voltage control unit includes a field-programmable gate array (FPGA) and a microcontroller unit (MCU) connected to each other. The FPGA is connected to the analog-to-digital converter (ADC), and the MCU is connected to the avalanche photodiode. The voltage control unit is used to acquire the trend of the overall noise and determine whether the avalanche photodiode has reached saturation output based on the trend. When the avalanche photodiode reaches saturation output, the minimum bias voltage of the avalanche photodiode is acquired. Based on the minimum bias voltage, the bias voltage of the avalanche photodiode is adjusted using a binary method, and the real-time output of the avalanche photodiode is acquired. When the real-time output is within the target output range, the target operating voltage of the time domain reflectometer is acquired based on the bias voltage corresponding to the real-time output within the target output range.

[0021] A computer device includes a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps described above.

[0022] A computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the steps described above.

[0023] The embodiments of the present invention have the following beneficial effects:

[0024] The bias voltage of the avalanche photodiode is adjusted using a binary method based on the minimum bias voltage until the real-time output of the avalanche photodiode is within the target output range. The binary method can quickly and accurately determine the optimal signal-to-noise ratio (SNR) point of the APD, and the target operating voltage of the time domain reflectometer is obtained based on the optimal SNR point of the APD, which effectively improves the efficiency and accuracy of determining the target operating voltage. When the bias voltage of the APD is set at the optimal SNR point, the sensitivity and dynamic range of the APD can usually reach the optimal state, thus ensuring the stability of the dynamic range of the OTDR. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] in:

[0027] Figure 1 This is a flowchart illustrating an embodiment of the adaptive control method for bias voltage provided by the present invention;

[0028] Figure 2 This is a schematic diagram of an embodiment of the adaptive control circuit for bias voltage provided by the present invention;

[0029] Figure 3 This is a schematic diagram of an embodiment of the adaptive control device for bias voltage provided by the present invention;

[0030] Figure 4 This is a structural block diagram of a computer device in one embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figure 1 , Figure 1 This is a flowchart illustrating an embodiment of the adaptive bias voltage control method provided by the present invention. The adaptive bias voltage control method provided by the present invention is used to control the bias voltage of an OTDR (Optical Time Domain Reflectometer) so that the OTDR's APD (Avalanche Photodiode) is at its optimal signal-to-noise ratio (SNR) point. The optimal SNR point of the APD refers to the point where the signal strength and noise level of the APD achieve the best balance. At the optimal SNR point, the APD can maximize the signal detection sensitivity and minimize the impact of noise. To find the optimal SNR point, a series of experiments and adjustments are usually required. In this embodiment, the operating point is adjusted by changing the bias voltage of the APD. As the bias voltage increases, the gain of the APD increases, but the noise level also increases. Finding the optimal SNR point of the APD, achieving the best balance between signal strength and noise level, results in the optimal SNR.

[0033] The adaptive control method for bias voltage provided by this invention includes the following steps:

[0034] S101: Obtain the overall noise of the diode unit, which includes an avalanche photodiode and an operational amplifier circuit.

[0035] In a specific implementation scenario, the overall noise of a diode unit, including an avalanche photodiode (APD) and an operational amplifier (APA) circuit, is acquired. The overall noise includes dark current noise caused by the dark current generated by the APD in the absence of light; the magnitude of the dark current is related to the APD's structure and materials. The presence of dark current leads to increased noise. In the APA circuit, components such as resistors and transistors generate thermal noise. The magnitude of thermal noise is related to the resistor's temperature, resistance value, and bandwidth. The amplifier itself in the APA circuit also introduces noise. This includes input noise, amplifier noise itself, and output noise. When searching for the optimal signal-to-noise ratio (SNR) of the APD, it is necessary to consider and collect this noise data in advance, and perform appropriate processing and analysis to obtain accurate results and the optimal SNR.

[0036] In one implementation scenario, the combined noise of the diode unit is acquired with the laser of the time-domain reflectometer (TD-RS) off. This avoids interference from the laser's optical signal on the APD measurement. When the laser is on, it generates a strong optical signal, which may saturate the APD or generate excessive current, making it difficult to accurately measure the APD's performance. By searching with the laser off, the influence of the laser's optical signal can be eliminated, resulting in more accurate measurement results. In this case, the acquired noise mainly comes from the dark current of the APD itself and the noise of the operational amplifier circuit, which better reflects the APD's performance.

[0037] In other implementation scenarios, the following methods can also be used to avoid interfering with the APD measurement:

[0038] In a time-domain reflectometer (TD-RS), filters can be used to select specific wavelengths of light signals to prevent interference from other wavelengths in the APD measurements. Filters can selectively transmit or block specific wavelengths of light, thereby reducing interference. APD measurements should be performed in a low-noise environment to avoid the influence of strong electromagnetic interference sources. Shielding measures can be taken to reduce the impact of external noise on the APD. For operational amplifier circuits, circuit design can be optimized to reduce noise introduction. Using low-noise amplifiers and optimizing the selection of resistors and capacitors can reduce noise introduced by the circuit itself. Noise can be reduced by controlling the APD's operating temperature. For example, using a thermostat or temperature control device to keep the APD operating at a stable temperature can reduce the impact of temperature changes on APD performance.

[0039] S102: Obtain the trend of the overall noise and determine whether the avalanche photodiode has reached saturation output based on the trend. If so, proceed to step S103.

[0040] In a specific implementation scenario, the noise change trend of the output collected by the ADC can be used to determine whether the avalanche photodiode has reached saturation output. When the APD reaches saturation output, its output signal will no longer increase linearly with the increase of the bias voltage, but tend to be stable or increase slightly.

[0041] An initial bias voltage can be set, and signal collection and analysis can be started. The noise of the APD output signal is collected by the ADC and recorded. The bias voltage is gradually increased, and signal collection and analysis are continued. The noise change trends at different bias voltages are compared. If the noise continues to increase or tends to be stable with the increase of the bias voltage and no longer increases significantly, it can be considered that the APD has reached saturation output.

[0042] S103: Obtain the minimum bias voltage of the avalanche photodiode, adjust the bias voltage of the avalanche photodiode by using the dichotomy method based on the minimum bias voltage, and simultaneously obtain the real-time output of the avalanche photodiode. When the real-time output is within the target output range, obtain the target working voltage of the time domain reflectometer according to the bias voltage corresponding to the real-time output within the target output range.

[0043] In a specific implementation scenario, when the APD reaches saturation output, obtain the bias voltage when the APD reaches saturation output as the minimum bias voltage Vb of the APD, and adjust the bias voltage by using the dichotomy method based on the minimum bias voltage. First, an initial bias voltage adjustment range can be determined according to the specifications and working requirements of the APD and the OTDR. The initial bias voltage adjustment range includes the minimum bias voltage Vb. Select an intermediate value within the initial bias voltage adjustment range as the initial bias voltage. For example, the minimum bias voltage Vb can be selected as the initial bias voltage.

[0044] Obtain the real-time output of the APD when the bias voltage is Vb. If the output is within the preset output range, it is considered that the current bias voltage (for example, Vb) is the optimal signal-to-noise ratio point of the APD, and the target working voltage of the OTDR can be obtained according to the current bias voltage. If the output is not within the preset output range, the bias voltage adjustment range can be adjusted according to the comparison of the output with the preset output range.

[0045] Assume that the initial bias voltage adjustment range is [a, b], where a < Vb < b, and the preset output range is [Fa, Fb]. If the real-time output x corresponding to the current bias voltage (for example, Vb) is less than Fa, the bias voltage adjustment range is adjusted to [Vb, b]. If the real-time output x corresponding to the current bias voltage (for example, Vb) is greater than Fb, the bias voltage adjustment range is adjusted to [a, Vb].

[0046] Select a new bias voltage based on the adjusted bias voltage range, for example, the midpoint of the adjusted bias voltage range (e.g., (Vb+b) / 2, or (a+Vb) / 2). Obtain the real-time output corresponding to the new bias voltage. If the output is within the preset output range, the current bias voltage is considered the optimal signal-to-noise ratio (SNR) point of the APD. If the output is not within the preset output range, repeat the steps of adjusting the bias voltage range based on the comparison between the output and the preset output range, and obtaining a new real-time output based on the adjusted bias voltage range, until a real-time output within the preset output range is obtained. The bias voltage corresponding to this real-time output within the preset output range is then taken as the optimal SNR point of the APD.

[0047] The binary search algorithm is a highly efficient search algorithm that rapidly approaches the target value by halving the search range each time. Compared to incremental methods, the binary search algorithm typically finds the optimal signal-to-noise ratio (SNR) point for the APD much faster. The binary search algorithm offers high accuracy because it continuously narrows the search range to approach the target value. By progressively adjusting the bias voltage and observing the output results in real time, the optimal SNR point for the APD can be determined more accurately. A key feature of the binary search algorithm is that it halves the search range in each iteration, meaning it avoids over-adjusting the bias voltage. By observing the output results in real time, adjustment can be stopped once the output falls within the target range, preventing over-adjustment that could lead to performance degradation or instability. The binary search algorithm can adaptively adjust the search range based on the real-time output results. If the output result is too high, the search range can be adjusted to half its lower value; if the output result is too low, the search range can be adjusted to half its higher value. This adaptability allows for a faster finding of the optimal SNR point for the APD.

[0048] In one implementation scenario, the bias voltage adjustment range is determined based on the minimum and maximum bias voltages supported by the APD. For example, if the minimum bias voltage of the APD is known to be Vmin and the maximum bias voltage is known to be Vmax, then the adjustable range can be selected as [Vmin, Vmax].

[0049] In another implementation scenario, the bias voltage adjustment range can be selected within the range of minimum and maximum bias voltages based on knowledge or experience. Alternatively, the bias voltage adjustment range can be selected within the range of minimum and maximum bias voltages by considering the specifications and performance parameters of the avalanche photodiode, as well as the performance requirements of the OTDR, such as the target output dynamic range.

[0050] In another implementation scenario, each APD has a room-temperature initial bias voltage. The room-temperature initial bias voltage of an APD refers to the initial bias voltage set by the APD at room temperature without any adjustment or optimization. This initial bias voltage is typically determined based on the APD's specifications and performance parameters, as well as the manufacturer's recommendations. Different APD models may have different room-temperature initial bias voltages. Obtaining the APD's room-temperature initial voltage and temperature coefficient is crucial. The temperature coefficient is the correlation coefficient between temperature and the APD's room-temperature initial voltage; the room-temperature initial voltage and temperature are positively correlated, approximating as a first-order linear function.

[0051] The current temperature of the APD is obtained by a temperature sensor or thermistor. The bias voltage adjustment range is obtained by combining the current temperature with the APD's initial bias voltage at room temperature and temperature coefficient.

[0052] Specifically, the bias voltage adjustment range can be obtained using the following formula:

[0053] a=(vbr-n)-k*(|T-25℃|)

[0054] b=(vbr+n)+k*(|T-25℃|)

[0055] Where vbr is the initial bias voltage at room temperature, k is the temperature coefficient, a is the minimum value of the bias voltage adjustment range, b is the maximum value of the bias voltage adjustment range, and n is a preset fixed value that can be set according to actual needs, for example, n=3.

[0056] The binary search method allows for the gradual adjustment of the avalanche photodiode's bias voltage, with real-time observation of the output. Once the real-time output falls within the target range, adjustment can be stopped, and the target operating voltage determined. This method ensures stable output within the target range, preventing performance degradation or instability caused by over-adjustment. A stable operating voltage is crucial for a time-domain reflectometer (TD-RS). Excessively high or low bias voltage can lead to output signal distortion or increased noise, affecting the accuracy and clarity of the reflected signal. By using the binary search method to obtain the target operating voltage, the APD's bias voltage can be precisely controlled, stabilizing it at its optimal value, thereby improving the T-RS's stability and signal quality. Furthermore, the binary search method avoids over-adjustment and frequent bias voltage adjustments, reducing system instability. By quickly and accurately determining the target operating voltage, system stability can be improved, maintaining output signal consistency and reliability.

[0057] The dynamic range of an OTDR refers to the maximum attenuation it can measure. Dynamic range is one of the important performance indicators of an OTDR. In optical fiber, the signal attenuates as the transmission distance increases. Dynamic range represents the difference between the minimum reflected light signal that an OTDR can detect and the maximum attenuation value. It is usually expressed in dB.

[0058] Setting the APD's bias voltage to the optimal signal-to-noise ratio (SNR) point ensures the OTDR's best dynamic range stability. The optimal SNR point is the point where the APD achieves the best signal amplification while minimizing noise. When the APD's bias voltage is set near the optimal SNR point, its sensitivity and dynamic range are typically at their best. This means the OTDR can accurately measure smaller reflected signals and high-attenuation regions while maintaining measurement stability; in other words, the OTDR's dynamic range stability is improved.

[0059] In one implementation scenario, when obtaining the real-time output of the APD via an analog-to-digital converter (ADC), the target output range is determined based on the number of bits in the ADC's output. For example, when the ADC output is 10 bits, the target output range is 1022(2). 10 -2)~1023(2 10 -1).

[0060] In one implementation scenario, the target operating voltage is obtained by subtracting a preset coefficient from the bias voltage corresponding to the real-time output within the target output range. The preset coefficient is a positive number, and its specific value can be set according to the design requirements of the OTDR, such as the required receiving sensitivity, dynamic range, and stability.

[0061] As described above, in this embodiment, the bias voltage of the avalanche photodiode is adjusted using a binary method based on the minimum bias voltage until the real-time output of the avalanche photodiode is within the target output range. The binary method can quickly and accurately determine the optimal signal-to-noise ratio (SNR) point of the APD, and obtain the target operating voltage of the time domain reflectometer based on the optimal SNR point of the APD, effectively improving the efficiency and accuracy of determining the target operating voltage. When the bias voltage of the APD is set at the optimal SNR point, the sensitivity and dynamic range of the APD can usually reach the optimal state, thus ensuring the stability of the dynamic range of the OTDR.

[0062] Please refer to the following: Figure 2 and Figure 1 , Figure 2This is a schematic diagram of an embodiment of the adaptive bias voltage control circuit provided by the present invention. The adaptive bias voltage control circuit 10 is used to implement the adaptive bias voltage control method described above, and includes an analog-to-digital converter (A / D) circuit 11, connected to an operational amplifier circuit (TIA+OP) and an avalanche photodiode (APD), for acquiring the real-time output of the avalanche photodiode and the combined noise of the avalanche photodiode and the operational amplifier circuit.

[0063] The voltage control unit 12 includes a field-programmable gate array (FPGA) 121 and a microcontroller unit (MCU) 122 connected to each other. The FPGA 121 is connected to the analog-to-digital converter circuit 11, and the MCU 122 is connected to the avalanche photodiode. The voltage control unit 12 is used to acquire the trend of the overall noise and determine whether the avalanche photodiode has reached saturation output based on the trend. When the avalanche photodiode reaches saturation output, the minimum bias voltage of the avalanche photodiode is acquired. Based on the minimum bias voltage, the bias voltage of the avalanche photodiode is adjusted using a binary method. At the same time, the real-time output of the avalanche photodiode is acquired. When the real-time output is within the target output range, the target operating voltage of the time domain reflectometer is acquired according to the bias voltage corresponding to the real-time output within the target output range.

[0064] The voltage control unit 12 is specifically used to obtain the initial bias voltage and temperature coefficient of the avalanche photodiode at room temperature, obtain the current temperature of the avalanche photodiode, obtain the bias voltage adjustment range based on the initial bias voltage, temperature coefficient and current temperature, and adjust the bias voltage within the bias voltage adjustment range using a binary method based on the minimum bias voltage.

[0065] The voltage control unit 12 is specifically used to obtain the bias voltage adjustment range according to the following formula:

[0066] a=(vbr-n)-k*(|T-25℃|)

[0067] b=(vbr+n)+k*(|T-25℃|)

[0068] Where vbr is the initial bias voltage at room temperature, k is the temperature coefficient, a is the minimum value of the bias voltage adjustment range, b is the maximum value of the bias voltage adjustment range, and n is a preset fixed value.

[0069] The adaptive control circuit 10 also includes a voltage calculation unit, which is used to subtract a preset coefficient from the bias voltage corresponding to the real-time output within the target output range to obtain the target operating voltage.

[0070] The voltage control unit 12 is specifically used to obtain the target output range based on the number of bits of the output of the analog-to-digital converter when the real-time output of the avalanche photodiode is obtained through the analog-to-digital converter.

[0071] The adaptive control circuit 10 also includes a control unit for driving the analog-to-digital conversion circuit 11 to acquire the combined noise of the diode unit when the laser of the time-domain reflectometer is turned off.

[0072] As described above, in this embodiment, the bias voltage of the avalanche photodiode is adjusted using a binary method based on the minimum bias voltage until the real-time output of the avalanche photodiode is within the target output range. The binary method can quickly and accurately determine the optimal signal-to-noise ratio (SNR) point of the APD, and obtain the target operating voltage of the time domain reflectometer based on the optimal SNR point of the APD, effectively improving the efficiency and accuracy of determining the target operating voltage. When the bias voltage of the APD is set at the optimal SNR point, the sensitivity and dynamic range of the APD can usually reach the optimal state, thus ensuring the stability of the dynamic range of the OTDR.

[0073] Please see Figure 3 , Figure 3 This is a schematic diagram of an embodiment of the adaptive bias voltage control device provided by the present invention. The adaptive bias voltage control device 20 controls the operating voltage of the time domain reflectometer. The detector part of the time domain reflectometer uses an avalanche photodiode and includes: a noise module 21, a judgment module 22, a voltage module 23, and an adjustment module 24.

[0074] Noise module 21 is used to acquire the overall noise of the diode unit when the laser of the time domain reflectometer is turned off. The diode unit includes an avalanche photodiode and an operational amplifier circuit. Judgment module 22 is used to acquire the trend of the overall noise and determine whether the avalanche photodiode has reached saturation output based on the trend. Voltage module 23 is used to acquire the minimum bias voltage of the avalanche photodiode when it reaches saturation output. Adjustment module 24 is used to adjust the bias voltage of the avalanche photodiode using a binary method based on the minimum bias voltage. While adjusting, it acquires the real-time output of the avalanche photodiode. When the real-time output is within the target output range, it acquires the target operating voltage of the time domain reflectometer based on the bias voltage corresponding to the real-time output within the target output range.

[0075] In one implementation scenario, the adjustment module 24 is used to obtain the initial bias voltage and temperature coefficient of the avalanche photodiode at room temperature, obtain the current temperature of the avalanche photodiode, obtain the bias voltage adjustment range based on the initial bias voltage, temperature coefficient and current temperature, and adjust the bias voltage within the bias voltage adjustment range using a binary method based on the minimum bias voltage.

[0076] In one implementation scenario, the adjustment module 24 is used to obtain the bias voltage adjustment range according to the following formula:

[0077] a=(vbr-n)-k*(|T-25℃|)

[0078] b=(vbr+n)+k*(|T-25℃|)

[0079] Where vbr is the initial bias voltage at room temperature, k is the temperature coefficient, a is the minimum value of the bias voltage adjustment range, b is the maximum value of the bias voltage adjustment range, and n is a preset fixed value.

[0080] In one implementation scenario, the adjustment module 24 is used to subtract a preset coefficient from the bias voltage corresponding to the real-time output within the target output range to obtain the target operating voltage.

[0081] In one implementation scenario, the adjustment module 24 is used to obtain the target output range based on the number of bits of the analog-to-digital converter when the real-time output of the avalanche photodiode is obtained through the analog-to-digital converter.

[0082] In one implementation scenario, noise module 21 is used to acquire the combined noise of the diode unit when the laser of the time domain reflectometer is turned off.

[0083] As described above, in this embodiment, the bias voltage of the avalanche photodiode is adjusted using a binary method based on the minimum bias voltage until the real-time output of the avalanche photodiode is within the target output range. The binary method can quickly and accurately determine the optimal signal-to-noise ratio (SNR) point of the APD, and obtain the target operating voltage of the time domain reflectometer based on the optimal SNR point of the APD, effectively improving the efficiency and accuracy of determining the target operating voltage. When the bias voltage of the APD is set at the optimal SNR point, the sensitivity and dynamic range of the APD can usually reach the optimal state, thus ensuring the stability of the dynamic range of the OTDR.

[0084] Figure 4 An internal structural diagram of a computer device in one embodiment is shown. This computer device can specifically be a terminal or a server. Figure 4 As shown, the computer device includes a processor, memory, and network interface connected via a system bus. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and may also store a computer program. When executed by the processor, this computer program enables the processor to implement an artificial intelligence-based food detection method. The internal memory may also store a computer program, which, when executed by the processor, enables the processor to implement the artificial intelligence-based food detection method. Those skilled in the art will understand that... Figure 4The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0085] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the following steps:

[0086] The method involves acquiring the overall noise of a diode unit, which includes an avalanche photodiode and an operational amplifier circuit; acquiring the trend of the overall noise; determining whether the avalanche photodiode has reached saturation output based on the trend; when the avalanche photodiode reaches saturation output, acquiring the minimum bias voltage of the avalanche photodiode; adjusting the bias voltage of the avalanche photodiode using a binary method based on the minimum bias voltage; acquiring the real-time output of the avalanche photodiode during adjustment; and when the real-time output is within the target output range, acquiring the target operating voltage of the time domain reflectometer based on the bias voltage corresponding to the real-time output within the target output range.

[0087] In one embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, causes the processor to perform the following steps:

[0088] The method involves acquiring the overall noise of a diode unit, which includes an avalanche photodiode and an operational amplifier circuit; acquiring the trend of the overall noise; determining whether the avalanche photodiode has reached saturation output based on the trend; when the avalanche photodiode reaches saturation output, acquiring the minimum bias voltage of the avalanche photodiode; adjusting the bias voltage of the avalanche photodiode using a binary method based on the minimum bias voltage; acquiring the real-time output of the avalanche photodiode during adjustment; and when the real-time output is within the target output range, acquiring the target operating voltage of the time domain reflectometer based on the bias voltage corresponding to the real-time output within the target output range.

[0089] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method of adaptive control of a bias voltage, characterized by, A bias voltage for controlling a time domain reflectometer, a probe part of the time domain reflectometer using an avalanche photodiode; The adaptive control method of the bias voltage comprises the following steps: Obtaining the comprehensive noise of a diode unit, the diode unit comprising the avalanche photodiode and an operational amplifier circuit; Obtaining the trend of the comprehensive noise, and determining whether the avalanche photodiode reaches saturation output based on the trend; When the avalanche photodiode reaches saturation output, obtaining the minimum bias voltage of the avalanche photodiode; Obtaining the initial bias voltage at room temperature and the temperature coefficient of the avalanche photodiode, obtaining the current temperature of the avalanche photodiode, and obtaining the bias voltage adjustment range according to the initial bias voltage at room temperature, the temperature coefficient and the current temperature; Adjusting the bias voltage of the avalanche photodiode based on the minimum bias voltage by using a dichotomy method, and obtaining the real-time output of the avalanche photodiode during the adjustment, when the real-time output is within a target output range, obtaining the target working voltage of the time domain reflectometer according to the bias voltage corresponding to the real-time output within the target output range; Wherein, the bias voltage adjustment range is obtained according to the following formula: a=(vbr-n)-k*(|T-25℃|) b=(vbr+n)+k*(|T-25℃|) Wherein, vbr is the initial bias voltage at room temperature, k is the temperature coefficient, a is the minimum value of the bias voltage adjustment range, b is the maximum value of the bias voltage adjustment range, and n is a preset fixed value.

2. The adaptive control method of bias voltage according to claim 1, wherein, The step of adjusting the bias voltage based on the minimum bias voltage by using a dichotomy method comprises: Adjusting the bias voltage within the bias voltage adjustment range based on the minimum bias voltage by using a dichotomy method.

3. The method of adaptive control of bias voltage according to claim 1, wherein, The step of obtaining the target working voltage of the time domain reflectometer according to the bias voltage corresponding to the real-time output within the target output range comprises: Subtracting a preset coefficient from the bias voltage corresponding to the real-time output within the target output range to obtain the target working voltage.

4. The method of adaptive control of bias voltage according to claim 1, wherein, Before the step of obtaining the target working voltage of the time domain reflectometer according to the bias voltage corresponding to the real-time output within the target output range, comprising: When obtaining the real-time output of the avalanche photodiode through an analog-to-digital converter, obtaining the target output range according to the output bit number of the analog-to-digital converter.

5. The method of adaptive control of bias voltage according to claim 1, wherein, The step of obtaining the comprehensive noise of the diode unit comprises: Obtaining the comprehensive noise of the diode unit under the condition that the laser of the time domain reflectometer is turned off.

6. An adaptive bias voltage control apparatus, characterized by comprising: A working voltage for controlling a time domain reflectometer, a probe part of the time domain reflectometer using an avalanche photodiode; The adaptive control device of the bias voltage comprises the following modules: A noise module, configured to obtain the comprehensive noise of a diode unit under the condition that the laser of the time domain reflectometer is turned off, the diode unit comprising the avalanche photodiode and an operational amplifier circuit; a judging module, configured to acquire a change trend of the comprehensive noise, and determine whether the avalanche photodiode reaches saturation output based on the change trend; a voltage module, configured to acquire a minimum bias voltage of the avalanche photodiode when the avalanche photodiode reaches saturation output; an adjusting module, configured to acquire an initial bias voltage at room temperature and a temperature coefficient of the avalanche photodiode, acquire a current temperature of the avalanche photodiode, acquire a bias voltage adjusting range according to the initial bias voltage at room temperature, the temperature coefficient and the current temperature, adjust the bias voltage of the avalanche photodiode based on the minimum bias voltage, acquire a real-time output of the avalanche photodiode during the adjustment, and acquire a target working voltage of the time domain reflectometer according to a bias voltage corresponding to the real-time output within a target output range when the real-time output is within the target output range. The bias voltage adjusting range is acquired according to the following formula: a = (vbr-n)-k*(|T-25℃|) b = (vbr+n)+k*(|T-25℃|) wherein vbr is the initial bias voltage at room temperature, k is the temperature coefficient, a is a minimum value of the bias voltage adjusting range, b is a maximum value of the bias voltage adjusting range, and n is a preset fixed value.

7. An adaptive bias voltage control circuit, characterized by comprising: An adaptive control method of a bias voltage is provided. The adaptive control circuit of the bias voltage comprises: an analog-to-digital conversion circuit connected to an operational amplifier circuit and an avalanche photodiode, configured to acquire a real-time output of the avalanche photodiode and a comprehensive noise of the avalanche photodiode and the operational amplifier circuit; a voltage control unit comprising a field programmable gate array and a micro control unit connected to each other, the field programmable gate array being connected to the analog-to-digital conversion circuit, and the micro control unit being connected to the avalanche photodiode, the voltage control unit being configured to acquire a change trend of the comprehensive noise, determine whether the avalanche photodiode reaches saturation output based on the change trend, acquire a minimum bias voltage of the avalanche photodiode when the avalanche photodiode reaches saturation output, adjust the bias voltage of the avalanche photodiode based on the minimum bias voltage, acquire a real-time output of the avalanche photodiode during the adjustment, and acquire a target working voltage of the time domain reflectometer according to a bias voltage corresponding to the real-time output within a target output range when the real-time output is within the target output range. 8.A computer readable storage medium storing a computer program, the computer program being executed by a processor to cause the processor to perform the steps of the method according to any one of claims 1 to 5. 9.A computer device comprising a memory and a processor, the memory storing a computer program, the computer program being executed by the processor to cause the processor to perform the steps of the method according to any one of claims 1 to 5.

Images