Analog quantity acquisition method and acquisition system with self-excitation test

Abstract

This invention provides an analog signal acquisition method and system with self-excitation testing, solving the problem of high noise introduced by existing engine analog signal acquisition and detection circuits. Based on the type of analog signal being acquired, a corresponding detection signal is generated through a DDS and an FPGA+DA converter. An analog switch controls the type of signal flowing into the AI ​​(AI) circuit. Based on the selected injection signal, a differential injection circuit balances the injection impedance to eliminate signal interference. This provides the engine analog signal acquisition circuit with functions for open / short circuit detection, filtering performance testing, bit function testing, and anti-interference capability testing. This invention is feature-rich, highly versatile, and has strong anti-interference capabilities, providing testing functions for various commonly used analog signal acquisition circuits, and is of great significance to the function and performance of detection signal acquisition circuits.

Description

Technical Field

[0001] This invention relates to the technical field of aero-engine testing, and in particular to an analog quantity acquisition method and system with self-excitation testing capability. Background Technology

[0002] Aircraft electromechanical systems contain a large number of analog signals such as pressure, temperature, rotational speed, and angle. With the increasing integration and generalization of electromechanical systems, higher demands are placed on the accuracy, speed, and precision of analog signal acquisition. Simultaneously, the failure modes of analog devices are increasing, and tolerance failures are more frequent, making the design of analog bit-tests (BITs) more challenging. Furthermore, typical bit-test circuits have relatively limited functionality; when weak signals are detected via bit-testing, the injection of the signal also introduces noise, failing to meet testing requirements under various operating conditions. Summary of the Invention

[0003] In view of this, the analog signal acquisition system with self-excitation testing provided by the present invention has strong anti-interference ability and eliminates interference from the system's acquired signals.

[0004] An analog signal acquisition system with self-excitation testing capability is disclosed. The system includes an analog switching circuit, which comprises a switching matrix and a differential injection circuit.

[0005] The input terminal of the switch matrix receives the actual analog signal transmitted from the outside and the detection signal generated by the signal generation circuit in the airborne system. It is used to select the detection signal and control whether to receive the external actual analog signal.

[0006] The input terminal of the differential injection circuit is connected to the output terminal of the switch matrix to simulate the superposition of input signals, amplify the superimposed signal, and send it to the back-end conditioning circuit for secondary processing.

[0007] Beneficial effects

[0008] This invention utilizes a DDS (Direct Digital Synthetic Array) frequency synthesizer and an "FPGA+DA converter" analog signal generation method to provide rich analog input test signals for analog signal acquisition systems with self-excited testing capabilities, improving system reusability and avoiding signal interference. The chip select control of the switch matrix provides four operating states: short-circuit, open-circuit, single-sided, and double-sided, enabling the system to adapt to different analog signal acquisition circuits. The balancing resistors of the AI ​​interface balance the interface impedance, ensuring the integrity of the analog signal acquisition. The analog differential injection circuit uses differential injection to eliminate the influence of interference signals on the analog signal acquisition, ensuring the accuracy of the analog signal acquisition. In addition to bit testing, it also features interference noise injection, circuit performance testing, open-circuit and short-circuit functional testing, and single / double-sided input signal reconfigurability, thus having a wider range of applications. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a functional principle block diagram of the present invention;

[0011] Figure 2 This is the circuit schematic diagram of the present invention. Detailed Implementation

[0012] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0013] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0014] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0015] It is also necessary to describe the components related to this disclosure rather than drawing them according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0016] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the aspects can be practiced without these specific details.

[0017] The analog test signal is generated by a DDS and an FPGA+DA converter. The DDS generates a frequency signal with adjustable period, phase, and amplitude. The FPGA minimum system unit generates the digital value of the analog signal, which is then converted back to an analog signal by the DA converter. A switch matrix consisting of four analog switches controls the switching between various operating modes of the system, realizing various testable functions, and is controlled by the FPGA for chip selection. See also Figure 1 An analog signal acquisition system with self-excitation testing capability includes an analog switching circuit, which comprises a switching matrix and a differential injection circuit.

[0018] The input of the switch matrix receives the actual analog signal transmitted from the outside and the detection signal generated by the signal generation circuit in the air. It is used to select the detection signal and control whether to receive the external actual analog signal, so as to realize the injection of different detection signals and correspond to different detection functions.

[0019] The input terminal of the differential injection circuit is connected to the output terminal of the switch matrix to simulate the superposition of input signals and amplify the superimposed signal. The analog differential injection circuit is used to collect interference in a differential form to ensure the accuracy of analog signal acquisition and send it to the back-end conditioning circuit for secondary processing.

[0020] This system addresses the problems of high noise, limited functionality, and poor versatility in existing engine analog signal acquisition and detection circuits. It generates corresponding detection signals based on the type of analog signal being acquired, such as voltage, current, and frequency, using a DDS and an FPGA+DA converter. Analog switches control the type of signal flowing into the AI ​​(frequency signal, analog signal (voltage / current), noise). Based on the selected injection signal, a differential injection circuit balances the injection impedance and eliminates signal interference, providing the engine analog acquisition circuit with functions for open / short circuit detection, filtering performance testing, bit-in-the-loop (BIT) function testing, and anti-interference capability testing.

[0021] As a specific implementation method provided in this case, the detection signal is an analog test signal, which includes a frequency signal with adjustable amplitude, phase and period generated by the DDS and a BIT detection signal and noise signal generated by the FPGA chip controlling the DA converter. The BIT detection signal generally includes voltage signal and current signal.

[0022] The switch matrix is ​​controlled by the FPGA chip of the airborne acquisition system. It can control the selection of detection signals and whether to receive external actual analog signals. Specifically, the switch matrix includes a first analog switch K1, a second analog switch K2, a third analog switch K3, and a fourth analog switch K4.

[0023] like Figure 2 As shown, the first analog switch K1 and the fourth analog switch K4 control the selection of the detection signal, while the second analog switch K2 and the third analog switch K3 control the selection of the actual analog signal. The purpose is to achieve open / short circuit detection, filtering performance testing, bit function testing, and anti-interference capability testing of the analog signal acquisition system through different selection states of the switch matrix.

[0024] Furthermore, to achieve input impedance balance, it is preferable to set input resistors with the same resistance value at the AI ​​terminal. The differential injection circuit includes a signal amplifier, resistors R1, R2, R3, R4, and R5, wherein...

[0025] One end of resistors R1 and R2 is connected to the inverting input of the signal amplifier, and the other end is connected to the first analog switch and the second analog switch, respectively. One end of resistors R3 and R4 is connected to the non-inverting input of the signal amplifier, and the other end is connected to the third analog switch and the fourth analog switch, respectively. The detection signal is injected into the input of the signal amplifier in a differential form. The differential injection circuit realizes the functions of impedance balance and eliminating analog signal acquisition interference in a differential injection form.

[0026] One end of resistor R5 is connected to the output terminal of resistor R1, and the other end is connected to the output terminal of the signal amplifier. This is used for negative feedback of the signal at the inverting input terminal of the signal amplifier to improve the stability of the output.

[0027] As a specific implementation method provided in this case, the switch matrix also includes multi-ports, such as... Figure 2 As shown, the switch matrix also includes multiple ports, see Table 1 for switch interface combination function comparison table. 。

[0028]

[0029] Table 1

[0030] From Table 1 and Figure 2 The first analog switch K1 corresponds to three input ports S1, open circuit port S14, short circuit port S15 and ground port S16. The three input ports S1 include port S11, port S12 and port S13.

[0031] The fourth analog switch K4 corresponds to three input ports S4, open circuit port S44, short circuit port S45, and ground port S46. The three input ports S4 include port S41, port S42, and port S43.

[0032] The three input ports S1 and S4 correspond to the frequency detection signal, analog detection signal, and noise injection generated by the signal generation circuit, respectively.

[0033] Short-circuit port S15 is shorted to short-circuit port S45, open-circuit port S14 and open-circuit port S44 are both in the open-circuit state, and grounding port S16 and grounding port S46 are grounded respectively;

[0034] The second analog switch K2 corresponds to two input ports S2, an open-circuit port S23, and a ground port S24. The two input ports S2 include port S21 and port S22.

[0035] The third analog switch K3 corresponds to two input ports S3, an open-circuit port S33, and a ground port S34. The two input ports S3 include port S31 and port S32.

[0036] The two input ports S2 and S3 correspond to the actual analog signal and the actual frequency signal, respectively. The open-circuit ports S23 and S33 are both in the open-circuit state, and the grounding ports S23 and S33 are grounded.

[0037] As a specific implementation method provided in this case, the switching between single-sided acquisition and double-sided acquisition modes is realized through a switch matrix, and the reconstruction of the single-sided signal of single-sided acquisition is also realized.

[0038] Secondly, an analog signal acquisition method with self-excitation testing is provided, using an analog signal acquisition system with self-excitation testing as described in part or all of the above. The analog signal acquisition method includes:

[0039] Step 1: Use a DDS (e.g., JDDS9910) to directly generate a frequency signal with adjustable period, phase, and amplitude. Use the FPGA minimum system unit (e.g., Virtex-4) to digitally output the analog signal to the output channel. The output channel converts the digital signal to be output into an analog signal through a DA converter chip (e.g., DEC7744). It can output interference noise signals, realizing the function of "FPGA + DA converter" to generate analog signals.

[0040] Step 2: Control the four analog switches (e.g., HI1-0548-5) by controlling the selection mode of the switch matrix chip select through the FPGA chip.

[0041] Step 3: Set input resistors with the same resistance value at the differential injection circuit terminal to achieve the effect of input impedance balance;

[0042] Step 4: The analog input signal through the differential injection circuit interface (AI interface) is then superimposed onto the analog acquisition signal through the analog differential injection circuit, and the interference is acquired in a differential form.

[0043] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. An analog quantity acquisition system with self-excitation test, characterized in that, It includes an analog switching circuit, which comprises a switching matrix and a differential injection circuit, wherein, The input terminal of the switch matrix receives the actual analog signal transmitted from the outside and the detection signal generated by the onboard signal generation circuit. It is used to select the detection signal and control whether to receive the external actual analog signal. It can control the selection of the detection signal and whether to receive the external actual analog signal. The input terminal of the differential injection circuit is connected to the output terminal of the switch matrix to simulate the superposition of input signals, amplify the superimposed signal, and send it to the back-end conditioning circuit for secondary processing. The detection signal is an analog test signal, which includes a frequency signal with adjustable amplitude, phase, and period generated by the DDS and a BIT detection signal and noise signal generated by the FPGA chip controlling the DA converter.

2. The analog acquisition system of claim 1, wherein, The switch matrix includes a first analog switch K1, a second analog switch K2, a third analog switch K3, and a fourth analog switch K4, wherein, The first analog switch K1 and the fourth analog switch K4 control the selection of the detection signal, and the second analog switch K2 and the third analog switch K3 control the selection of the actual analog signal.

3. The analog acquisition system of claim 2, wherein, The differential injection circuit includes a signal amplifier, resistors R1, R2, R3, R4, and R5, wherein... One end of resistors R1 and R2 is connected to the inverting input terminal of the signal amplifier, and the other end is connected to the first analog switch and the second analog switch, respectively. One end of resistors R3 and R4 is connected to the non-inverting input terminal of the signal amplifier, and the other end is connected to the third analog switch and the fourth analog switch, respectively. The detection signal is injected into the input terminal of the signal amplifier in a differential form. The differential injection circuit realizes the functions of impedance balance and elimination of analog signal acquisition interference in a differential injection form. One end of resistor R5 is connected to the output terminal of resistor R1, and the other end is connected to the output terminal of the signal amplifier, for signal negative feedback at the inverting input terminal of the signal amplifier.

4. The analog acquisition system of claim 3, wherein, The switch matrix also includes multiple ports. The first analog switch K1 corresponds to three input ports S1, open-circuit port S14, short-circuit port S15 and ground port S16. The three input ports S1 include port S11, port S12 and port S13. The fourth analog switch K4 corresponds to three input ports S4, open circuit port S44, short circuit port S45 and ground port S46. The three input ports S4 include port S41, port S42 and port S43. The three input ports S1 and the three input ports S4 respectively correspond to the frequency detection signal, analog detection signal and noise injection generated by the signal generation circuit; The short-circuit port S15 is shorted to the short-circuit port S45, the open-circuit port S14 and the open-circuit port S44 are both in the open-circuit state, and the grounding port S16 and the grounding port S46 are respectively grounded; The second analog switch K2 corresponds to two input ports S2, an open-circuit port S23, and a ground port S24. The two input ports S2 include port S21 and port S22. The third analog switch K3 corresponds to two input ports S3, an open-circuit port S33, and a ground port S34. The two input ports S3 include port S31 and port S32. The two input ports S2 and the two input ports S3 correspond to the actual analog signal and the actual frequency signal, respectively. The open-circuit ports S23 and S33 are both in an open-circuit state, and the ground ports S24 and S34 are grounded.

5. The analog quantity acquisition system with self-excitation test according to claim 4, characterized in that, The switching matrix enables the switching between single-sided and double-sided acquisition modes, and also enables the reconstruction of single-sided signals acquired from single-sided acquisition.

6. An analog quantity acquisition method with self-excitation test, characterized in that, Using the analog signal acquisition system with self-excitation testing as described in any one of claims 1 to 5, the analog signal acquisition method includes: Step 1: Use DDS to directly generate frequency signals with adjustable period, phase, and amplitude, and use the FPGA minimum system unit to output the analog signal to the output channel. The output channel converts the digital signal to be output into an analog signal through the DA converter chip. It can output interference noise signals, realizing the function of FPGA and DA converter to generate analog signals. Step 2: Control the four analog switches by controlling the selection mode of the switch matrix chip select through the FPGA chip; Step 3: Set input resistors with the same resistance value at the differential injection circuit terminal to achieve the effect of input impedance balance; Step 4: The analog input signal through the differential injection circuit interface is then superimposed onto the analog acquisition signal through the analog differential injection circuit, and the interference is acquired in a differential form.

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