A DA converter circuit for a fiber optic gyroscope with zero-adjustment function

Abstract

This invention relates to a DA conversion circuit for a fiber optic gyroscope with zero-adjustment function, belonging to the field of fiber optic gyroscope technology. The circuit first uses a DA conversion unit to convert the digital angular rate to an analog voltage, then a bipolar conversion module to convert the voltage polarity, a gain configuration module to adjust the voltage gain, a compensation factor module to generate a compensation factor, and a zero-adjustment module to achieve circuit zeroing. Finally, a filtering and adjustment module performs bandwidth limiting, noise filtering, and output range adjustment, ultimately outputting an analog voltage signal with the required angular rate. This invention improves the circuit's output accuracy and stability, enabling precise, real-time conversion of the fiber optic gyroscope's digital angular rate to an analog signal.

Description

Technical Field

[0001] This invention relates to the field of fiber optic gyroscope technology, and in particular to a DA conversion circuit for a fiber optic gyroscope with zero-adjustment function. Background Technology

[0002] A fiber optic gyroscope is an angular rate sensor based on the Sagnac effect. Its core working principle dictates that its final output is a physical quantity proportional to the input angular rate. Although digital fiber optic gyroscope technology is becoming increasingly mature, analog-output fiber optic gyroscopes remain indispensable in critical scenarios with extremely high requirements for real-time performance and redundancy safety, such as aerospace attitude control and guidance equipment control. Analog-based fiber optic gyroscopes typically use analog circuits to directly process Sagnac phase signals, reducing the delays and potential failure points introduced by digital signal conversion, improving system response speed and overall reliability. Furthermore, their tolerance to electromagnetic interference is sometimes superior to digital systems, providing more robust performance in complex electromagnetic environments. Simultaneously, many existing inertial navigation systems or stabilization platforms are built based on analog interfaces; analog-output fiber optic gyroscopes are directly compatible with and seamlessly integrated into these existing devices, avoiding the high costs and complexity associated with interface conversion or complete system replacement.

[0003] In analog-output fiber optic gyroscopes, the DA converter circuit is the key bridge for directly outputting analog angular rate information. Modern high-performance fiber optic gyroscopes generally adopt a digital closed-loop scheme, using a digital signal processor to accurately measure the feedback phase required to cancel the Sagnac phase shift. This phase value exists in digital form and needs to be converted into an analog voltage output in real time by the DA converter circuit to characterize the angular rate information detected by the fiber optic gyroscope.

[0004] Currently, research on DA conversion circuits is mostly focused on control systems, with no research specifically on DA conversion circuits for fiber optic gyroscopes. Independent digital-to-analog conversion control research for analog output fiber optic gyroscopes has not yet been conducted in China. Existing publicly available DA conversion circuit technologies, such as DA conversion circuits designed for PWM phase-shift control, DA conversion circuit element methods proposed at the electro-optic device level, and DA conversion circuits focusing on reference voltage adjustment, are not designed for fiber optic gyroscope applications. When applied to fiber optic gyroscopes, they exhibit numerous shortcomings, specifically lacking zero-adjustment, bandwidth limiting and setting functions, output range setting functions, and gain adjustment functions. These deficiencies fail to meet the high precision and adaptability requirements of fiber optic gyroscopes for DA conversion circuits, making it difficult to achieve accurate and efficient conversion of the fiber optic gyroscope's digital angular rate to analog signals.

[0005] Meanwhile, traditional digital output fiber optic gyroscopes directly output internally processed digital angular rate signals. This digital output requires a series of processes such as encoding, framing, transmission, and decoding, which introduces a small but not negligible communication delay. In contrast, analog output fiber optic gyroscopes can provide compatibility, real-time performance, reliability, and ease of use based on user and system requirements. They can be used "plug and play" with existing analog interface inertial systems and control systems. Therefore, there is an urgent need for a high-performance DA conversion circuit that is suitable for fiber optic gyroscope application scenarios to solve the above-mentioned defects of existing DA conversion circuits. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a DA converter circuit for fiber optic gyroscopes with zero-adjustment function. This circuit achieves accurate conversion of the fiber optic gyroscope's angular rate from digital to analog, improving the accuracy, stability, and fidelity of the converted analog voltage signal. It adapts to the analog output application requirements of fiber optic gyroscopes and enables "plug-and-play" compatibility with analog interface systems. The technical solution adopted by this invention is as follows:

[0007] A DA conversion circuit for a fiber optic gyroscope with zero-adjustment function is provided. The DA conversion circuit for a fiber optic gyroscope with zero-adjustment function includes a reference source circuit, a DA conversion unit, a bipolar conversion module, a gain configuration module, a zero-adjustment module, a filter adjustment module, and a compensation factor adjustment module. A zero-adjustment resistor is configured as an external adjustment element for the zero-adjustment function and is connected to the compensation factor adjustment module.

[0008] The reference source circuit is used to provide a reference voltage for the entire DA conversion circuit;

[0009] The DA conversion unit is used to convert the digital angular rate information demodulated from the fiber optic gyroscope into an analog voltage signal;

[0010] The bipolar conversion module connects the DA conversion unit and the gain configuration module, and is used to convert the unipolar analog voltage output by the DA conversion unit into a bipolar analog voltage that meets the application requirements of fiber optic gyroscopes.

[0011] The gain configuration module, connected in series between the bipolar conversion module and the zero-adjustment module, is used to amplify / reduce the analog voltage after bipolar conversion by a certain proportion, thereby configuring the output voltage range.

[0012] The compensation adjustment factor module is connected in series between the reference source circuit and the zero adjustment module. It is used to generate a compensation factor signal with the same magnitude but opposite sign as the zero offset of the output voltage of the gain configuration module.

[0013] The zero-adjustment module, connected in series between the gain configuration module, the compensation adjustment factor module, and the filter adjustment module, is used to add the zero-offset voltage signal output by the gain configuration module and the compensation factor signal generated by the compensation adjustment factor module.

[0014] The filtering adjustment module connects the zero-adjustment module and the external analog interface system, and is used to perform bandwidth control and filtering on the zero-offset voltage signal output by the zero-adjustment module.

[0015] Optionally, the DA conversion unit is provided with only one analog voltage output interface, which is directly connected to the signal input terminal of the bipolar conversion module. The unipolar analog voltage signal after digital-to-analog conversion is output to the bipolar conversion module to provide a signal source for subsequent polarity conversion processing.

[0016] Optionally, the bipolar conversion module is directly connected to the analog voltage output terminal of the DA conversion unit to receive the unipolar analog voltage signal output by the DA unit. This unipolar analog voltage signal is the original input for the bipolar conversion module to perform polarity conversion. The bipolar conversion module is connected to the reference reference voltage output by the reference source circuit as the midpoint reference for polarity conversion, which is the reference basis for realizing unipolar to bipolar conversion. The output terminal of the bipolar conversion module is directly connected to the signal input terminal of the gain configuration module to transmit the converted bipolar voltage signal to the gain configuration module without loss, thus forming the connecting link of the entire signal processing chain.

[0017] Optionally, the gain configuration module has only one analog signal input terminal, which is directly connected to the analog voltage output terminal of the bipolar conversion module to receive the positive and negative symmetrical bipolar analog voltage signal output by the module. This bipolar analog voltage signal is the original signal source for the module to perform gain adjustment. It also has only one analog signal output terminal, which is directly connected to the first signal input terminal of the zeroing module to completely transmit the bipolar voltage signal after gain adjustment to the zeroing module.

[0018] Optionally, the zero-adjustment resistor is a two-pin precision adjustable resistor, whose two pins are directly connected between the two-stage input subtraction circuit inside the compensation adjustment factor module, serving as an adjustment component for the feedback loop of the two-stage subtraction circuit.

[0019] Optionally, the zeroing module has two independent signal input terminals. The first input terminal is directly connected to the output terminal of the gain configuration module to receive the bipolar voltage signal formed after gain adjustment. The second input terminal is directly connected to the output terminal of the compensation adjustment factor module to receive the zero-position compensation output generated by it.

[0020] Optionally, the output of the zeroing module is directly connected to the input of the filter adjustment module, transmitting the unbiased voltage signal after zero offset cancellation to the filter adjustment module as the original signal for filter adjustment and bandwidth limitation.

[0021] Optionally, under the coordinated control of SYNC, SCLK, and SDIN signals, the DA conversion unit performs digital-to-analog conversion on the input 16-bit angular rate digital quantity with reference to the reference voltage, and outputs a 0 to 5V unipolar analog voltage signal that is proportional to the amplitude of the digital quantity.

[0022] Optionally, the DA conversion unit uses the XDDZ5064 chip as its core hardware.

[0023] Optionally, when the DA conversion unit outputs 0V, after differential operation, the bipolar conversion module outputs a negative voltage with the same amplitude but opposite polarity as the reference voltage; when the DA conversion unit outputs the reference voltage, the bipolar conversion module outputs an equal amount of positive voltage; when the DA conversion unit outputs an intermediate value, the reference voltage outputs a voltage value corresponding to the positive and negative ranges.

[0024] This invention provides a DA conversion circuit for a fiber optic gyroscope with zero-adjustment function. The technical solution provided by the embodiments of this invention brings at least the following beneficial effects:

[0025] (1) Precise zeroing and adjustable gain and output range. The zero offset is offset by the compensation factor module and the zeroing module, which improves the zero accuracy of the circuit output. At the same time, the gain can be flexibly adjusted by the gain configuration module and the output range can be set in two layers by the filter adjustment module, which can adapt to the diverse application needs of fiber optic gyroscopes.

[0026] (2) High anti-interference and signal fidelity. The filtering adjustment module adopts a second-order filter architecture, which can realize flexible bandwidth setting, effectively filter out high-frequency noise and switching ripple, optimize signal phase response and amplitude flatness, and improve the stability and fidelity of angular rate output signal.

[0027] (3) Excellent adaptability and real-time performance. It adopts a bipolar conversion architecture to realize positive and negative voltage output. It is designed for fiber optic gyroscopes to realize accurate real-time conversion of angular rate digital quantity to analog quantity. The output signal can be directly connected to the analog interface system to realize "plug and play". It solves the communication delay problem of traditional digital output fiber optic gyroscopes and is suitable for high-end and high-reliability application scenarios.

[0028] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0029] 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.

[0030] Figure 1 A schematic diagram illustrating the composition principle of a DA conversion circuit for a fiber optic gyroscope;

[0031] Figure 2 A schematic diagram of the DA conversion circuit used in fiber optic gyroscopes. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] Before describing the technical solution of the present invention in detail, the technical background and technical terms involved in the technical solution will be explained first:

[0034] Zeroing: This technique, achieved through circuit design, actively cancels the zero-point offset generated during the operation of the DA conversion circuit. It ensures that the output analog voltage signal is precisely zero when there is no angular rate digital input (or the input is zero). This is the core function for improving the zero-point accuracy of the circuit output. In the implementation logic of this invention, zeroing is not an independent function of a single module, but rather a collaborative process between the compensation factor module and the zeroing module. First, the compensation factor module uses an operational amplifier as its core to build a subtraction circuit, generating a compensation factor with the same amplitude but opposite sign as the circuit's zero-point offset signal. Then, the zeroing module superimposes this compensation factor with the voltage signal that has a zero-point deviation after gain configuration. The compensation factor cancels the zero-point offset in the voltage signal, thereby restoring the circuit output to a precise zero position. This solves the problem of large zero-point deviation in traditional DA conversion circuits and ensures the conversion accuracy of the fiber optic gyroscope's angular rate analog voltage signal.

[0035] Figure 1 This is a schematic diagram illustrating the principle of a DA converter circuit for a fiber optic gyroscope. The DA converter circuit for a fiber optic gyroscope with zero-adjustment function is structured as a combination of a serial signal processing link and a multi-module power supply / reference signal parallel supply architecture. It includes a reference source circuit, a DA conversion unit, a bipolar conversion module, a gain configuration module, a zero-adjustment module, a filter adjustment module, and a compensation factor adjustment module. A zero-adjustment resistor is configured as an external adjustment element for the zero-adjustment function and connected to the compensation factor adjustment module. The physical connections of each component are tightly coupled with its functional implementation. Specific details are as follows:

[0036] 1. Reference source circuit;

[0037] The reference source circuit receives an externally supplied +5V DC voltage and an externally input 15V voltage signal. These two voltage signals serve as the operating power input for the reference source circuit. It directly receives +5V and 15V power from the external power supply system, providing the basic energy for the internal voltage regulation and reference generation circuits. This is a prerequisite for the entire DA conversion circuit to achieve voltage reference conversion. The reference source circuit has one output signal terminal (+5VREF reference voltage), as detailed below:

[0038] This output is a high-precision, high-stability 5V reference voltage signal, which serves as the core reference for the entire DA conversion circuit. This signal is transmitted in parallel to the DA conversion unit, the bipolar conversion module, and the compensation adjustment factor module, providing a voltage reference for the DA conversion unit's digital-to-analog conversion, a reference for the bipolar conversion module's polarity conversion, and a reference for the compensation signal calculation in the compensation adjustment factor module. It is a crucial output for ensuring the accuracy of the circuit's signal processing.

[0039] The reference source circuit regulates, filters, and calibrates the externally input +5V and 15V voltages to generate a +5VREF reference voltage, which serves as the signal processing reference for the entire circuit. Through the precise distribution of multiple output +5V reference voltages, a stable and interference-free circuit operation foundation is established, ensuring the signal processing accuracy and operational stability of the DA conversion unit, bipolar conversion module, and compensation adjustment factor module.

[0040] 2. DA conversion unit;

[0041] The DA conversion unit is the core module of the digital-to-analog conversion circuit used in this fiber optic gyroscope. It is responsible for converting the digital angular rate information demodulated by the fiber optic gyroscope into an analog voltage signal. Its structure, interface, signal interaction, and functions are as follows:

[0042] (1) Hardware core and selection;

[0043] In this invention, the DA conversion unit uses the XDDZ5064 chip as the core hardware. This chip is adapted to the conversion requirements of digital signals of fiber optic gyroscopes, has high-precision digital-to-analog conversion capability, and can meet the accuracy requirements of fiber optic gyroscope angular rate signal conversion.

[0044] (2) Input interface and signal type;

[0045] The DA converter unit is equipped with multiple input interfaces to receive external control, data, and power signals, specifically including:

[0046] Digital control and data input interface: The SYNC synchronization signal, SCLK clock signal, and SDIN data signal are connected to the external signal input, which together constitute the SPI communication interface. The SYNC synchronization signal is used to synchronously trigger data transmission, the SCLK clock signal provides a clock reference for data transmission, and the SDIN data signal transmits the 16-bit angular rate digital quantity output by the fiber optic gyroscope demodulation, which is the core channel for digital signal input.

[0047] Power input interface: Connects to an external power supply VEE (+5V) to provide a stable operating voltage for the internal circuitry of the chip and ensure the normal operation of the chip.

[0048] Reference voltage input interface: Receives the +5VREF reference voltage output from the reference source circuit. This voltage is the core basis for the DA conversion unit to achieve accurate digital-to-analog conversion, and determines the amplitude and accuracy of the converted analog voltage.

[0049] (3) Output interface and signal transmission;

[0050] The DA conversion unit has only one analog voltage output interface, which is directly connected to the signal input terminal of the bipolar conversion module. It outputs the unipolar analog voltage signal after digital-to-analog conversion to the bipolar conversion module, providing a signal source for subsequent polarity conversion processing.

[0051] (4) Working principle;

[0052] Under the coordinated control of the SYNC, SCLK, and SDIN signals of the SPI communication interface, the DA conversion unit uses a +5VREF reference voltage as a reference to perform digital-to-analog conversion on the input 16-bit angular rate digital quantity, outputting a 0- to 5V unipolar analog voltage signal proportional to the amplitude of the digital quantity. This conversion process strictly follows the linear correspondence between the digital quantity and the analog voltage, ensuring accurate mapping from the angular rate digital quantity to the analog voltage. It is the first step in the entire circuit's signal conversion and directly determines the fundamental accuracy of subsequent analog signal processing.

[0053] The DA conversion unit is the core bridge connecting the fiber optic gyroscope digital demodulation system and the analog signal processing link. It is used to perform accurate conversion of digital angular rate information into unipolar analog voltage, providing reliable analog signal input for subsequent signal processing stages such as bipolar conversion, gain configuration, and zero adjustment compensation. It is the basic unit for realizing the conversion of digital to analog quantities in fiber optic gyroscopes and directly affects the conversion accuracy and signal fidelity of the entire DA conversion circuit.

[0054] 3. Bipolar conversion module;

[0055] The bipolar conversion module is a functional module in the DA conversion circuit used in fiber optic gyroscopes that realizes voltage polarity adaptation. It connects the DA conversion unit and the gain configuration module. Its function is to convert the unipolar analog voltage output by the DA conversion unit into a bipolar analog voltage that meets the application requirements of fiber optic gyroscopes. Its interface connection, circuit logic, working principle and functional positioning are as follows:

[0056] (1) Input / output interfaces and their connections;

[0057] Main signal input: directly connected to the analog voltage output terminal of the DA conversion unit, receiving the unipolar analog voltage signal output by it. This signal is the original input for the module to perform polarity conversion.

[0058] Reference voltage input: The +5VREF reference voltage output from the reference source circuit is connected as the midpoint reference for polarity conversion and is the core reference for realizing unipolar to bipolar conversion.

[0059] Signal output interface: The output terminal is directly connected to the signal input terminal of the gain configuration module, and transmits the converted bipolar voltage signal to the next module without loss, forming a key link in the entire signal processing chain.

[0060] (2) Circuit architecture and component configuration;

[0061] The bipolar conversion module employs a differential operational circuit architecture centered around an operational amplifier. Components include matched resistors R1 and R2 (R1=R2) and a high-precision operational amplifier. The output voltage of the DA conversion unit is connected to the signal input terminal of the operational amplifier, and the +5VREF reference voltage is connected to the reference input terminal of the operational amplifier. Resistors R1 and R2 form the proportional matching network of the differential circuit, providing symmetrical circuit conditions for polarity conversion.

[0062] (3) Working principle;

[0063] The bipolar conversion module uses +5VREF as the voltage reference point and completes polarity conversion through differential operation logic. Its conversion logic is based on the symmetrical characteristics of the circuit.

[0064] Basic conversion logic: The unipolar voltage output by the DA conversion unit has a lower limit of 0V and an upper limit of +5VREF. The bipolar conversion module performs differential calculation between this unipolar voltage and the +5VREF reference voltage to shift the voltage reference point from 0V to +5VREF / 2, thereby realizing the reversal and expansion of voltage polarity.

[0065] The specific conversion process is as follows: When the DA converter outputs 0V, after differential operation, the module outputs a negative voltage with the same amplitude but opposite polarity as +5VREF; when the DA converter outputs +5VREF, the module outputs an equal positive voltage; when the DA converter outputs an intermediate value, the module outputs a voltage value corresponding to the positive and negative ranges. Ultimately, the unipolar voltage output by the DA converter is completely converted into a symmetrical bipolar voltage signal with 0V as the midpoint, achieving a precise transition from unipolar to bipolar voltage range.

[0066] The bipolar conversion module accurately converts unipolar analog voltage to bipolar analog voltage, overcoming the polarity limitation of the native output of the DA conversion unit. It generates an analog voltage that conforms to the bidirectional variation characteristics of the fiber optic gyroscope's angular rate signal, adapting to the output requirements of the fiber optic gyroscope for positive and negative angular rate detection. As a crucial link connecting the digital-to-analog conversion core and subsequent gain adjustment, its conversion accuracy directly depends on the stability of the +5VREF reference voltage and the matching degree of resistors R1 and R2. Through high-precision circuit configuration, the module ensures the linearity and symmetry of the voltage after polarity conversion, providing a high-quality bipolar signal source for the amplitude adjustment of the subsequent gain configuration module. This is a prerequisite for the entire circuit to achieve wide-range, high-precision analog output.

[0067] 4. Gain configuration module;

[0068] The gain configuration module is the core functional module in the DA conversion circuit of this fiber optic gyroscope, enabling precise voltage amplitude adjustment. Connected in series between the bipolar conversion module and the zero-adjustment module, its function is to proportionally amplify / reduce the amplitude of the analog voltage after bipolar conversion, allowing for flexible configuration of the output voltage range. Simultaneously, it provides a standardized voltage signal source for subsequent zero-adjustment compensation, adapting to the analog voltage output requirements of the fiber optic gyroscope in different application scenarios. The interface connections, circuit architecture, working principle, and functional characteristics of this module are all designed around high-precision gain adjustment, as described in detail below:

[0069] (1) Interface connection relationship;

[0070] The gain configuration module is a crucial component for adjusting the amplitude of signals before and after the stage. It adopts a direct-connect signal transmission design, eliminating additional signal conversion losses and ensuring the accuracy of gain adjustment. The specific input and output connections are as follows:

[0071] Input interface: Only one analog signal input terminal is provided, which is directly connected to the analog voltage output terminal of the bipolar converter module to receive the positive and negative symmetrical bipolar analog voltage signal output by it. This signal is the original signal source for the module to perform gain adjustment, and its linearity and symmetry directly determine the basic quality of gain adjustment.

[0072] Output interface: Only one analog signal output terminal is provided, which is directly connected to the first signal input terminal of the zeroing module. The bipolar voltage signal after gain adjustment is completely transmitted to the zeroing module, providing an amplitude-adapted voltage signal for subsequent zero offset compensation, thus forming a seamless connection of the entire signal processing link.

[0073] (2) Circuit architecture and component configuration;

[0074] The gain configuration module adopts a negative feedback amplifier circuit architecture with an operational amplifier as its core. This architecture features precise gain adjustment, stable output signal, and high linearity, and is fully compatible with the high-precision requirements of fiber optic gyroscope DA conversion circuits. The components and configuration are as follows:

[0075] Active components: High-precision, low-drift operational amplifiers are used to effectively avoid gain errors caused by the amplifier's own performance deviations, ensuring signal fidelity during voltage amplification.

[0076] Passive components: The input resistor and the feedback resistor form a proportional adjustment network. By adjusting the resistance ratio of the feedback resistor, the gain coefficient of the circuit can be accurately set. All resistors are high-precision and high-stability surface mount resistors to reduce the influence of ambient temperature and electromagnetic interference on the resistance value and ensure the long-term stability of the gain coefficient.

[0077] Circuit configuration characteristics: In this circuit design, by precisely matching the resistance ratio of the input and feedback resistors, the module gain coefficient is configured to -3, which realizes the inverting proportional amplification of the input voltage. Moreover, the entire circuit has no extra redundant components, which simplifies the architecture and reduces signal loss and error introduction.

[0078] (3) Working principle;

[0079] The gain configuration module relies on the linear operation characteristics of the negative feedback amplifier circuit to adjust the amplitude of the voltage signal output by the bipolar conversion module with a fixed gain coefficient. The entire process maintains a linear correspondence between the voltage and the angular rate of the fiber optic gyroscope, with no signal distortion. The specific working logic is as follows:

[0080] Adjusting the logic basis: The gain of the negative feedback amplifier circuit is determined by the ratio of the input resistor to the feedback resistor. In the inverting amplification mode, the output voltage and the input voltage satisfy Uo1=G×Uoo (where Uo1 is the module output voltage, G is the gain coefficient, and Uoo is the bipolar conversion module input voltage), where G=-3, achieving a 3-fold inverting amplification of the input voltage.

[0081] The specific adjustment process is as follows: The module receives a -5V to +5V symmetrical bipolar voltage from the bipolar conversion module. After inverting amplification with a gain coefficient of -3, it outputs a -15V to +15V bipolar voltage signal. During amplification, the positive and negative characteristics of the input voltage reverse with the inverting amplification, and the voltage amplitude is precisely amplified by a factor of 3. Any input voltage value follows this linear amplification law, ensuring accurate mapping between the angular rate signal and the analog voltage. The inherent characteristics of the negative feedback architecture can effectively suppress circuit temperature drift, zero drift, and component parameter deviations, enabling the module to maintain a constant gain coefficient even in complex working environments (such as high and low temperatures and strong electromagnetic environments in aerospace), avoiding voltage output deviations caused by gain drift.

[0082] (4) Implement the function;

[0083] Achieving precise proportional adjustment of voltage amplitude: By presetting the gain coefficient, the standardized output voltage of the bipolar conversion module is extended to the voltage range required for fiber optic gyroscope applications. In this invention, the amplitude amplification from -5V to +5V to -15V to +15V is completed, which meets the range requirements of high-end inertial systems and control systems for the analog voltage output of fiber optic gyroscopes.

[0084] Provides core adjustment means for setting the output range: As a primary adjustment module for setting the circuit output range, it can flexibly adjust the gain coefficient by changing the resistance ratio to achieve the configuration of different voltage output ranges and adapt to the personalized needs of fiber optic gyroscopes in different application scenarios.

[0085] Provide a standardized signal source for the zero-adjustment module: After adjusting the voltage amplitude to the target range, provide a voltage signal with amplitude matching to the zero-adjustment module, so that the zero-position compensation factor can be designed according to a fixed ratio, simplifying the circuit complexity of the zero-adjustment module and improving the accuracy of zero-adjustment compensation.

[0086] The gain configuration module is the core component in the entire DA conversion circuit, enabling customized voltage range. Positioned between bipolar conversion and zero-adjustment compensation, its performance directly impacts subsequent signal processing and the accuracy of the final output voltage. From a signal processing perspective, the module converts standardized bipolar voltages into the target amplitude voltage required for fiber optic gyroscope applications, a crucial step in achieving "plug-and-play" functionality, allowing the output voltage to directly match the input requirements of the analog interface system. Regarding output range setting, the module, as a primary adjustment unit, works in conjunction with the secondary adjustment of the filter adjustment module to achieve precise dual-layer setting of the circuit's output range, overcoming the shortcomings of traditional DA conversion circuits lacking output range setting functionality. In terms of overall accuracy, the module's high-precision gain adjustment ensures a linear proportional relationship between the digital angular rate and the final analog voltage, avoiding fiber optic gyroscope angle measurement errors caused by amplitude adjustment deviations, making it a vital module for guaranteeing the accuracy of the entire DA conversion circuit. Meanwhile, the negative feedback amplifier circuit architecture of this module takes into account gain accuracy, signal stability and configuration flexibility, and is fully adapted to the stringent requirements of high-end application scenarios such as aerospace and guidance equipment control for fiber optic gyroscopes, providing core amplitude adjustment guarantee for the entire circuit to achieve high reliability and high precision analog voltage output.

[0087] 5. Zero-adjustment resistor and compensation adjustment factor module;

[0088] The zero-adjustment resistor and compensation adjustment factor module are the core functional units of this fiber optic gyroscope's DA conversion circuit for achieving high-precision zero-position compensation. They work together as a unified whole. The compensation adjustment factor module is the main generator of the zero-position compensation signal, while the zero-adjustment resistor is its core adjustment element. The module is connected in series between the reference source circuit and the zero-adjustment module. Its core function is to generate a compensation factor signal with the same amplitude but opposite sign as the zero-position offset of the output voltage from the gain configuration module. This provides a precise and adjustable compensation basis for the zero-position offset cancellation of the zero-position module, completely solving the technical defects of traditional DA conversion circuits, such as lack of zero-adjustment function and large zero-position deviation. The specific connection relationships are divided into two parts: the internal connection of the zero-adjustment resistor and compensation adjustment factor module, and the overall connection between the compensation adjustment factor module and the external circuit.

[0089] Internal connection between the zero-adjustment resistor and the compensation adjustment factor module: Zero-adjustment resistor R zero This is a two-pin precision adjustable resistor, with its two pins directly connected between the two-stage input subtraction circuits inside the compensation adjustment factor module. As the core adjustment component of the feedback loop of the two-stage subtraction circuit, it forms an electrical connection with the operational amplifier and fixed resistor within the module. This connection method allows changes in the zero-adjustment resistor's value to directly alter the equivalent operational ratio of the two-stage subtraction circuit, thereby precisely adjusting the amplitude and polarity of the compensation factor signal output by the module. This is the core electrical connection design for achieving accurate zero-point compensation calibration.

[0090] Overall Connection between the Compensation Adjustment Factor Module and External Circuits: As an independent functional unit within the circuit, the compensation adjustment factor module only has external electrical connections with the reference source circuit and the zeroing module, with no other redundant connections. Regarding the connection to the reference source circuit, the reference voltage input terminal of the compensation adjustment factor module is directly connected to the +5V VREF output terminal of the reference source circuit. It receives the high-precision, high-stability 5V reference voltage provided by the reference source circuit. This voltage is the core calculation reference for generating the compensation factor signal using the two-stage subtraction circuit within the module, and is the compensation output voltage U. pz The basic input for the operation. The connection with the zero-adjustment module: The compensation signal output terminal of the compensation adjustment factor module is directly connected to the second signal input terminal of the zero-adjustment module. This transmits the zero-offset compensation factor signal (compensation output voltage Upz) generated by the module to the zero-adjustment module. This, together with the offset voltage signal Uo1 output by the gain configuration module and connected to the first input terminal of the zero-adjustment module, forms a dual-input signal superposition relationship, providing a precise compensation signal source for subsequent addition to cancel the zero-offset.

[0091] 6. Zeroing module;

[0092] The zero-adjustment module is the execution module for achieving precise zero-offset cancellation using the DA conversion circuit in this fiber optic gyroscope. It is connected in series between the gain configuration module, the compensation adjustment factor module, and the filter adjustment module. It is a dual-input single-output signal superposition unit. Its function is to add the zero-offset voltage signal output by the gain configuration module and the compensation factor signal generated by the compensation adjustment factor module. By utilizing the characteristics that the two signals have equal amplitudes but opposite signs, the zero-offset in the voltage signal is completely canceled out. This allows the circuit to accurately return the output voltage to 0 when there is no angular rate digital input or when the input value is zero. This completely solves the technical defect of large zero-offset in traditional DA conversion circuits and provides a high-quality voltage signal source without zero-offset for the subsequent filter adjustment module.

[0093] The zero-adjustment module has two independent signal input terminals: the first input terminal is directly connected to the output terminal of the gain configuration module, receiving a -15V to +15V bipolar voltage signal Uo1 after gain adjustment. This signal is an analog voltage signal carrying the effective angular rate of the zero-position offset. The second input terminal is directly connected to the output terminal of the compensation adjustment factor module, receiving the zero-position compensation output Upz generated by it. This compensation signal is a dedicated compensation factor signal with the same amplitude but opposite sign as the zero-position offset in Uo1 after adjustment by the zero-adjustment resistor Rzero. Both input signals adopt a direct-connection transmission design without intermediate conversion components, minimizing signal transmission loss and interference, and ensuring the accuracy of superposition calculation.

[0094] The output of the zeroing module is directly connected to the input of the filter adjustment module, transmitting the unbiased voltage signal after zero offset cancellation to the next module as the original signal for filter adjustment and bandwidth limiting. The entire module is built with a high-precision, low-drift operational amplifier as the core to construct an addition superposition circuit, and uses high-matching, low-drift surface mount resistors to form the signal input and operation network. The circuit architecture is simple and has no redundant components, which not only ensures the linearity and accuracy of the addition superposition operation, but also improves the module's anti-interference ability and working stability.

[0095] The zero-adjustment module operates on the principle of linear addition and cancellation. It utilizes an internal addition circuit to perform real-time superposition of the two input voltage signals Uo1 and Upz. Because the zero-offset signals in the compensation signal Upz and Uo1 have equal amplitudes but opposite signs, their superposition completely cancels out the zero-offset component, retaining only the effective voltage signal precisely corresponding to the fiber optic gyroscope's angular rate. Furthermore, the entire superposition process strictly adheres to linear operation rules, preventing any interference or distortion to the amplitude or phase of the effective angular rate signal, thus ensuring the fidelity of the angular rate analog signal. During operation, this module performs only the dedicated function of zero-offset cancellation, completely decoupled from the signal processing functions of other modules in the circuit. The accuracy of its superposition operation is determined solely by the performance of the internal operational amplifier and the resistor matching, making it minimally affected by external environmental factors. Even in harsh working environments such as aerospace and guidance equipment control, it maintains a stable zero-offset cancellation effect, effectively improving the zero-offset output accuracy and operational reliability of the entire DA conversion circuit. Meanwhile, this module works in synergy with the compensation adjustment factor module, which provides a flexibly adjustable and precise compensation signal, while the zeroing module acts as the execution end to complete the final zero-position cancellation. The combination of the two realizes a closed loop of "precise generation + effective execution" for circuit zero-position compensation, enabling the entire DA conversion circuit to have active and precise zero-position calibration capabilities. It also provides a key guarantee for the high precision of the fiber optic gyroscope's analog output signal and is an important link in realizing the "plug-and-play" adaptation of the entire circuit to analog interface systems.

[0096] 7. Filter adjustment module;

[0097] The filtering and adjustment module is the final signal processing module of the DA conversion circuit used in this fiber optic gyroscope. Connecting the zeroing module to the external analog interface system, it is the core functional module for implementing circuit bandwidth limiting, noise filtering, and secondary setting of the output range. Its function is to precisely control and filter the zero-offset voltage signal output from the zeroing module. Simultaneously, it works with the gain configuration module to complete the final setting of the output range, ultimately outputting a high-precision, high-stability, and highly anti-interference target angular rate analog voltage signal, achieving "plug-and-play" compatibility with external analog inertial and control systems. This module is also a key design feature that addresses the lack of bandwidth limiting and setting functions in traditional DA conversion circuits, fully adapting to the stringent requirements of signal fidelity and stability in high-end applications such as aerospace and guidance equipment control.

[0098] The input of this module is directly connected to the output of the zeroing module, adopting a direct-connect signal transmission design without intermediate conversion components. This minimizes signal loss and interference during transmission, receiving a pure voltage signal that retains only the effective angular rate information of the fiber optic gyroscope after zeroing. The output serves as the final signal output port of the entire DA conversion circuit, directly interfacing with an external analog interface system to output a target analog voltage signal that meets the system's input requirements. The entire module internally uses a high-precision operational amplifier as the core to build a second-order filter architecture, and uses high-matching, low-temperature drift, and electromagnetic interference-resistant precision resistors and capacitors to form a filter network. The circuit architecture is simple and highly targeted, and all component parameters are precisely matched according to the transmission characteristics of the fiber optic gyroscope angular rate signal and the interface requirements of the external system. This ensures the accuracy of filtering and bandwidth limiting, and improves the module's working stability under complex conditions.

[0099] The working principle of the filter adjustment module revolves around the electrical characteristics of a second-order filter. On one hand, it utilizes the inherent characteristics of the second-order filter to limit and set the bandwidth of the input signal. Based on the application scenario of the fiber optic gyroscope and the signal reception requirements of the external system, it can precisely adjust the cutoff frequency of the filter, effectively filtering out high-frequency noise, switching ripple, and other interference components in the signal. Furthermore, it provides good phase response and amplitude flatness near the cutoff frequency, avoiding signal distortion and phase shift, significantly improving the fidelity of the angular rate output signal and the overall anti-interference capability of the system. On the other hand, this module undertakes the function of secondary setting of the circuit output range, working in synergy with the primary gain adjustment of the gain configuration module. Besides adjusting the amplification ratio through the gain configuration module to achieve the initial setting of the output range, it can also further precisely adjust and calibrate the voltage range after zeroing by adjusting the parameters of the internal resistors and capacitors of the second-order filter. Ultimately, it achieves flexible and precise setting of the entire circuit's output range, meeting the personalized requirements of different analog interface systems for the input voltage range.

[0100] During operation, this module only performs bandwidth limiting, filtering, and output range calibration on the signal, without causing any interference or distortion to the effective components of the fiber optic gyroscope's angular rate analog signal. It maintains a linear correspondence between the signal and the angular rate, and its second-order filter architecture possesses excellent frequency selectivity, minimal attenuation of the effective signal, and strong suppression of interference signals. Even in harsh operating environments such as high and low temperatures, strong electromagnetic fields, and vibrations, the core components exhibit high parameter stability, consistently maintaining stable filtering and bandwidth limiting effects, effectively ensuring the consistency and reliability of the entire DA conversion circuit's output signal. Furthermore, as the final link in the entire signal processing chain, the module's processing performance directly determines the quality of the final output analog voltage signal. By filtering out various interferences, precisely controlling the bandwidth, and completing the final calibration of the output range, it ensures that the output target signal perfectly matches the reception requirements of the external analog system. Direct connection can be achieved without additional interface conversion circuits, truly realizing "plug and play" for the fiber optic gyroscope's analog output. This also overcomes the technical deficiencies of existing DA conversion circuits in bandwidth control and flexible output range setting, providing crucial signal quality assurance for the entire DA conversion circuit in high-end, high-reliability applications.

[0101] Figure 2 This is a schematic diagram of the DA converter circuit used in a fiber optic gyroscope. It fully presents the entire signal processing chain from the digital input of angular rate to the target analog voltage output. It clearly demonstrates the cascading relationship, signal interaction logic, and core operational principles of the reference source circuit, DA converter unit, bipolar conversion module, gain configuration module, compensation factor module, zero-adjustment module, and filter adjustment module. Each module completes signal processing in the order of "digital-to-analog conversion → polarity conversion → gain adjustment → zero-position compensation → filter width determination," and each stage matches the voltage calculation formula, achieving high-precision, distortion-free conversion of digital angular rate to analog voltage. A detailed description follows:

[0102] 1. Overall signal flow direction;

[0103] Figure 2 The entire circuit operates based on the +5V reference voltage (VREF) output by the reference source circuit as the core calculation benchmark. This reference voltage provides a unified voltage reference for the DA conversion unit, bipolar conversion module, and compensation factor module, and is the core parameter of all voltage calculation formulas. The 16-bit angular rate digital quantity and SPI control command output from the external fiber optic gyroscope demodulation control are input to the DA conversion unit. After being processed by each module in sequence, the final output of the target analog voltage signal that accurately corresponds to the angular rate is output by the filtering and adjustment module. The entire link maintains a linear correspondence between the digital quantity and the analog voltage, with no signal distortion.

[0104] 2. Principles and signal operations of each module;

[0105] (1) DA conversion unit: the core conversion from digital quantity to unipolar analog voltage;

[0106] The DA converter unit is the core of the entire circuit's digital-to-analog conversion. Figure 2 The middle module is the starting module for signal processing. Its input terminal receives two external inputs: one is the SPI control command (including SYNC synchronization, SCLK clock, and SDIN data transmission signal (the digital value of the angular rate output by the fiber optic gyroscope demodulation control)), and the other is the VREF=5V reference voltage provided by the reference source circuit and the external operating power supply (VEE(+5V)). The output terminal is directly connected to the input terminal of the bipolar conversion module, transmitting the converted unipolar analog voltage to it.

[0107] Driven synchronously by SPI control commands, this module converts a 16-bit angular rate digital quantity into a unipolar analog voltage (Uo) ranging from 0 to 5V. The converted voltage value is determined by the 16-bit code D written to the DAC and the reference voltage VREF, serving as the original signal source for all subsequent analog voltage calculations.

[0108] (2) Bipolar conversion module: linear conversion of unipolar to bipolar voltage;

[0109] Bipolar conversion module in Figure 2 The module connects the DA conversion unit and the gain configuration module. Its input terminals are connected to the unipolar voltage Uo output by the DA conversion unit and the VREF=5V reference voltage of the reference source circuit, respectively. The module is equipped with matching resistors R1 and R2, and the circuit design strictly follows the symmetry principle of R1=R2. The output terminal is directly connected to the input terminal of the gain configuration module and outputs the converted bipolar voltage Uoo.

[0110] This module performs unipolar to bipolar voltage conversion based on VREF=5V. The core calculation formula for the output voltage under its bipolar architecture is as follows:

[0111] ;

[0112] Wherein, Uo is the 0-5V unipolar voltage output by the DA conversion unit, and D is the 16-bit code written to the DAC. After calculation by this formula, the module accurately converts the 0-5V unipolar voltage into a positive and negative symmetrical bipolar voltage from -5V to +5V, realizing the effective output of the negative angular rate signal and adapting to the physical characteristics of the positive and negative bidirectional changes in the angular rate of the fiber optic gyroscope.

[0113] (3) Gain configuration module: proportional amplitude amplification of bipolar voltage;

[0114] Gain configuration module in Figure 2It is connected in series between the bipolar conversion module and the zero-adjustment module, and adopts a negative feedback amplifier circuit architecture as its core design. The input terminal is connected to the output Uoo (-5V to +5V) of the bipolar conversion module. The gain coefficient is set by adjusting the negative feedback amplification ratio inside the module. The output terminal is directly connected to the first signal input terminal of the zero-adjustment module, and outputs the voltage Uo1 after gain adjustment.

[0115] In this invention, the gain coefficient of the module is configured to be -3, and the bipolar voltage from -5V to +5V is amplified in reverse phase and proportionally. After calculation, a bipolar voltage output from -15V to +15V is formed. This gain adjustment process maintains the linear mapping between voltage and angular rate, providing a standardized amplitude signal for subsequent zero-position compensation. At the same time, the gain coefficient can be flexibly changed by adjusting the circuit amplification ratio, realizing the first-level setting of the output range.

[0116] (4) Compensation Factor Module: Accurate generation of zero-position offset compensation factor;

[0117] The compensation factor module is in Figure 2 The module is an independent signal compensation unit that inputs signals to the zero-adjustment module in parallel with the gain configuration module. It is the core module for realizing the circuit's zero-adjustment function. Its input terminal is connected to a 5V reference voltage (VREF) from the reference source circuit. Internally, the module uses an operational amplifier to build a two-stage subtraction circuit, configured with fixed resistors R4, R5, R7, and R8, and an adjustable zero-position resistor Rzero. Its output terminal is directly connected to the second signal input terminal of the zero-adjustment module, outputting a zero-position compensation voltage Upz. This module adjusts Rzero to compensate for the zero-position of the output Uo1 of the gain configuration module. The calculation formula for the compensation output Upz is as follows:

[0118] ;

[0119] exist Figure 2 In the compensation adjustment factor module, the zero-adjustment resistor Rzero is connected across the feedback loop of the first-stage operational amplifier, forming the feedback network of the second-stage operational amplifier together with the fixed resistor R7. In the above calculation formula, R11 + R12 is essentially the complete resistance value of the zero-adjustment resistor Rzero, i.e., R11 + R12 = Rzero. This is a mathematical expression that splits the adjustable resistor into two fixed resistance parts, used to more clearly describe the proportional calculation logic of the compensation factor generation. In practice, after the zero-adjustment cancellation factor is determined, it can also be converted into two independent resistor elements in the circuit whose sum is equal to Rzero. The advantage of doing this is to improve the stability of the system's zero-adjustment compensation. The first term in the above formula... It is the base compensation voltage after the output of the first-stage op-amp is amplified by the second-stage op-amp; the second term The adjustable compensation component is introduced by the zero-adjustment resistor Rzero. By adjusting Rzero (R11+R12), the amplitude and polarity of the compensation output Upz can be precisely changed to achieve zero-position compensation calibration.

[0120] Calculated using the above formula, the module can accurately generate a compensation factor signal with the same amplitude but opposite sign as the zero offset signal output by the gain configuration module, providing a precise compensation basis for subsequent zero offset cancellation. Furthermore, by adjusting Rzero, the amplitude and polarity of the compensation factor can be flexibly adjusted to adapt to the zero compensation requirements under different operating conditions.

[0121] (5) Zeroing module: precise cancellation of zero offset;

[0122] Zeroing module in Figure 2 Connecting the gain configuration module, compensation factor module, and filter adjustment module, it is a dual-input single-output signal superposition unit. The first input terminal is connected to Uo1 (-15V to +15V) output from the gain configuration module, the second input terminal is connected to the compensation voltage Upz output from the compensation factor module, and the output terminal is directly connected to the input terminal of the filter adjustment module, outputting a zero-adjusted offset voltage signal.

[0123] The module works by additive superposition cancellation, which linearly superimposes the offset voltage signal from the gain configuration module with the compensation signal from the compensation factor module. The zero offset in the voltage signal is completely canceled by the compensation factors with equal amplitude and opposite sign. This ensures that the output voltage is accurately zero when there is no angular rate digital input (or the input is zero), thus completely solving the problem of large zero deviation in traditional DA conversion circuits and improving the zero accuracy of the circuit output.

[0124] (6) Filtering adjustment module: final setting of bandwidth limit and output range;

[0125] The filter adjustment module is Figure 2 The last signal processing module in the entire circuit is the final output unit. The input terminal is connected to the offset-free voltage signal output by the zeroing module. The module adopts a second-order filter architecture design. The output terminal is the signal output port of the entire DA conversion circuit, which outputs the target analog voltage signal that precisely corresponds to the angular rate of the fiber optic gyroscope.

[0126] This module performs two core functions: First, it uses a second-order filter to limit and set bandwidth, effectively filtering out high-frequency noise and switching ripple introduced during signal transmission. This provides good phase response and amplitude flatness for the signal near the cutoff frequency, improving the fidelity of the angular rate signal and the system stability. Second, it enables secondary setting of the output range. In conjunction with the primary gain adjustment of the gain configuration module, by adjusting the parameters of the second-order filter, the voltage range after gain adjustment can be further precisely adjusted. Ultimately, this allows for flexible setting of the entire circuit's output range, enabling the target analog voltage to directly match the input requirements of various analog interface systems, achieving "plug and play".

[0127] Figure 2 The modules within the system form a seamless collaborative link through direct signal transmission, and all modules use VREF=5V of the reference source circuit as a unified calculation benchmark to ensure the consistency and accuracy of voltage calculations at each stage. The DA conversion unit completes the digital-to-analog conversion, providing a standardized unipolar analog voltage for subsequent modules; the bipolar conversion module achieves polarity conversion, expanding the voltage output range and adapting to the signal characteristics of the fiber optic gyroscope; the gain configuration module achieves amplitude adjustment through negative feedback amplification, completing the first-level setting of the output range; the compensation factor module generates a precise compensation factor based on a dedicated formula, which, together with the signal from the gain configuration module, is input to the zero-adjustment module to complete zero-point compensation; the filtering adjustment module completes the second-level setting of bandwidth limitation, noise filtering, and output range through second-order filtering, ultimately outputting a high-precision, highly stable, and highly anti-interference target analog voltage signal.

[0128] In summary, this invention incorporates a compensation factor module and a zero-adjustment module. The compensation factor module generates a compensation factor with the same amplitude but opposite sign as the zero-position offset. The zero-adjustment module superimposes the compensation factor with the voltage after gain adjustment to achieve precise zero-adjustment, solving the problem of large zero-position deviation in traditional DA conversion circuits and effectively improving the zero-position accuracy of the circuit output, thus ensuring the conversion accuracy of the fiber optic gyroscope's angular rate analog signal. The filtering adjustment module of this invention adopts a second-order filter architecture, which not only enables flexible bandwidth limitation and setting but also effectively filters out high-frequency noise and switching ripple in the signal. It provides good phase response and amplitude flatness near the cutoff frequency, improving the fidelity of the fiber optic gyroscope's output angular rate signal and system stability, and enhancing the system's anti-interference capability. This invention employs a bipolar architecture conversion module, realizing the conversion from 0 to 5V unipolar voltage to -5V to +5V bipolar voltage, giving the circuit positive and negative range voltage output capability, adapting to the analog output polarity requirements of the fiber optic gyroscope, and expanding the circuit's application range. The gain configuration module of this invention adopts a negative feedback amplifier circuit architecture, which can flexibly adjust the gain by adjusting the circuit amplification ratio. Simultaneously, in conjunction with the filter adjustment module, it can complete the dual-layer setting of the circuit output range, achieving flexible adjustment of the output range. This solves the problem of traditional DA conversion circuits lacking gain adjustment and output range setting functions. The output voltage range can be adjusted according to the application requirements of the fiber optic gyroscope, making it more adaptable. The DA conversion circuit of this invention is specifically designed for fiber optic gyroscopes, achieving accurate and real-time conversion of the fiber optic gyroscope's angular rate from digital to analog. The output analog voltage signal can be directly interfaced with existing analog interface inertial systems and control systems, achieving "plug and play." This solves the communication delay problem introduced by encoding and transmission processes in traditional digital output fiber optic gyroscopes, improving the real-time performance and reliability of fiber optic gyroscopes, and adapting to the needs of high-end, high-reliability applications such as aerospace and guidance equipment control. The DA conversion circuit for fiber optic gyroscopes with zero-adjustment function of this invention has a reasonable structural design, with clearly defined and coordinated functions for each module. It achieves multiple functions such as zero-adjustment, gain adjustment, bandwidth setting, and output range setting, overcoming many shortcomings of existing technologies. It can accurately convert the digital to analog angular rate of the fiber optic gyroscope, and the output analog voltage signal has high accuracy, strong stability, and good anti-interference capability. It can be directly used as the analog output signal of the fiber optic gyroscope to interface with existing analog interface systems, achieving "plug and play". The circuit of this invention is built using mature electronic components and circuit architecture, making it easy to process, assemble, and debug. Production costs are controllable, allowing for mass production. It is adaptable to the application requirements of various analog output fiber optic gyroscopes and has broad application prospects in aerospace, guidance equipment control, inertial navigation systems, stabilization platforms, and other fiber optic gyroscope application fields, possessing significant industrial practicality.

[0129] The specific embodiments described above do not constitute a limitation on the scope of protection of this disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A DA converter circuit for a fiber optic gyroscope with zero-adjustment function, characterized in that, The DA conversion circuit for the fiber optic gyroscope with zero-adjustment function includes a reference source circuit, a DA conversion unit, a bipolar conversion module, a gain configuration module, a zero-adjustment module, a filter adjustment module, and a compensation factor adjustment module. A zero-adjustment resistor is also configured as an external adjustment element for the zero-adjustment function and connected to the compensation factor adjustment module. The reference source circuit is used to provide a reference voltage for the entire DA conversion circuit; The DA conversion unit is used to convert the digital angular rate information demodulated from the fiber optic gyroscope into an analog voltage signal; The bipolar conversion module connects the DA conversion unit and the gain configuration module, and is used to convert the unipolar analog voltage output by the DA conversion unit into a bipolar analog voltage that meets the application requirements of fiber optic gyroscopes. The gain configuration module, connected in series between the bipolar conversion module and the zero-adjustment module, is used to amplify / reduce the analog voltage after bipolar conversion by a certain proportion, thereby configuring the output voltage range. The compensation adjustment factor module is connected in series between the reference source circuit and the zero adjustment module. It is used to generate a compensation factor signal with the same magnitude but opposite sign as the zero offset of the output voltage of the gain configuration module. The zero-adjustment module, connected in series between the gain configuration module, the compensation adjustment factor module, and the filter adjustment module, is used to add the zero-offset voltage signal output by the gain configuration module and the compensation factor signal generated by the compensation adjustment factor module. The filtering adjustment module connects the zero-adjustment module and the external analog interface system, and is used to perform bandwidth control and filtering on the zero-offset voltage signal output by the zero-adjustment module.

2. The DA converter circuit for a fiber optic gyroscope with zero-adjustment function according to claim 1, characterized in that, The DA conversion unit has only one analog voltage output interface, which is directly connected to the signal input terminal of the bipolar conversion module. It outputs the unipolar analog voltage signal after digital-to-analog conversion to the bipolar conversion module, providing a signal source for subsequent polarity conversion processing.

3. The DA converter circuit for a fiber optic gyroscope with zero-adjustment function according to claim 1, characterized in that, The bipolar conversion module is directly connected to the analog voltage output of the DA conversion unit, receiving the unipolar analog voltage signal output by the unit. This unipolar analog voltage signal is the original input for the bipolar conversion module to perform polarity conversion. The bipolar conversion module is connected to the reference voltage output by the reference source circuit, which serves as the midpoint reference for polarity conversion and is the reference basis for realizing unipolar to bipolar conversion. The output of the bipolar conversion module is directly connected to the signal input of the gain configuration module, transmitting the converted bipolar voltage signal to the gain configuration module without loss, thus forming the connecting link of the entire signal processing chain.

4. The DA conversion circuit for a fiber optic gyroscope with zero-adjustment function according to claim 1, characterized in that, The gain configuration module has only one analog signal input terminal, which is directly connected to the analog voltage output terminal of the bipolar conversion module to receive the positive and negative symmetrical bipolar analog voltage signal output by the module. This bipolar analog voltage signal is the original signal source for the module to adjust the gain. It also has only one analog signal output terminal, which is directly connected to the first signal input terminal of the zeroing module to transmit the bipolar voltage signal after gain adjustment to the zeroing module.

5. The DA converter circuit for a fiber optic gyroscope with zero-adjustment function according to claim 1, characterized in that, The zero-adjustment resistor is a two-pin precision adjustable resistor. Its two pins are directly connected between the two-stage input subtraction circuit inside the compensation adjustment factor module, serving as the adjustment component of the feedback loop of the two-stage subtraction circuit.

6. The DA converter circuit for a fiber optic gyroscope with zero-adjustment function according to claim 1, characterized in that, The zeroing module has two independent signal input terminals. The first input terminal is directly connected to the output terminal of the gain configuration module and receives the bipolar voltage signal formed after gain adjustment. The second input terminal is directly connected to the output terminal of the compensation adjustment factor module and receives the zero-position compensation output generated by it.

7. The DA converter circuit for a fiber optic gyroscope with zero-adjustment function according to claim 6, characterized in that, The output of the zeroing module is directly connected to the input of the filter adjustment module, transmitting the unbiased voltage signal after zero offset cancellation to the filter adjustment module as the original signal for filter adjustment and bandwidth limitation.

8. The DA converter circuit for a fiber optic gyroscope with zero-adjustment function according to claim 1 or 2, characterized in that, Under the coordinated control of SYNC, SCLK, and SDIN signals, the DA conversion unit performs digital-to-analog conversion on the input 16-bit angular rate digital quantity with reference voltage as the reference, and outputs a 0 to 5V unipolar analog voltage signal that is proportional to the amplitude of the digital quantity.

9. The DA converter circuit for a fiber optic gyroscope with zero-adjustment function according to claim 8, characterized in that, The DA conversion unit uses the XDDZ5064 chip as its core hardware.

10. The DA converter circuit for a fiber optic gyroscope with zero-adjustment function according to claim 3, characterized in that, When the DA converter outputs 0V, after differential operation, the bipolar converter outputs a negative voltage with the same amplitude but opposite polarity as the reference voltage; when the DA converter outputs the reference voltage, the bipolar converter outputs an equal amount of positive voltage; when the DA converter outputs an intermediate value, the reference voltage outputs the voltage value corresponding to the positive and negative ranges.

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