Non-intrusive and digitally-triggered narrow pulse current signal sampling circuit

Abstract

The utility model relates to a non-intrusive and digitally-triggered narrow pulse current signal sampling circuit. The circuit comprises an integrating circuit, an amplifying and pulse broadening circuit, a sampling trigger circuit, an analog signal filter, a digital filter circuit and a master control circuit, the non-intrusive current sensor and the integrating circuit acquire narrow pulse current signal-analog quantity, the non-intrusive current sensor electromagnetically induces magnetic field change around a wire to generate induced current, and the integrating circuit integrates the induced current; the amplification and pulse broadening circuit is used for amplifying and broadening the narrow pulse current signal-analog quantity; the sampling trigger circuit sends a trigger signal-digital quantity based on the amplified and broadened narrow pulse current signal-analog quantity; the analog signal filter performs analog quantity filtering on the amplified and broadened narrow pulse current signal; the digital filter circuit filters the trigger signal-digital quantity; and the master control circuit receives the filtered trigger signal-digital quantity, and filters and samples the filtered narrow pulse current signal-analog quantity.

Description

TECHNICAL FIELD

[0001] The utility model relates to signal sampling, specifically relates to a narrow pulse current signal sampling circuit of non -invasive, digital trigger. BACKGROUND

[0002] The collection of narrow pulse current signals has wide application in communication, radar, medical treatment and other fields, but its collection and processing has been facing many challenges. The traditional method often cannot meet the requirements of high time resolution and high spatial resolution at the same time, and the real -time performance and accuracy are also insufficient.

[0003] The traditional current sampling mode is to increase the sampling resistance in the loop, must reserve in the design process, cannot sample in the position without sampling reservation, the flexibility is lower, the sampling resistance is greatly influenced by temperature and other environments, the sampling is easy to heat when the current is large, there is certain safety risk, especially to the sampling in some high -voltage system, in order to guarantee the reliability of control system, must do isolation processing, increase system design complexity and cost.

[0004] At the same time, narrow pulse signals are characterized by short pulse width and fast rising edge, which require the data acquisition module to have sufficient time resolution and spatial resolution. Specifically, the time resolution refers to the minimum time interval that the sampling system can achieve, i.e. the highest sampling rate that can be achieved. The spatial resolution is the minimum voltage value that can be measured.

[0005] General signal collection must be directly performed at the high end or low end of the circuit. In either case, the collection circuit must be connected to the loop being collected. At the same time, the pulse current signal may have a pulse width as short as microseconds or even shorter, so the sampling system must have a very high sampling rate to capture the complete waveform of the signal.

[0006] At the same time, the voltage amplitude of narrow pulse signals is relatively small, possibly only tens of millivolts or even lower. Ordinary data acquisition modules cannot distinguish small voltage changes, and these small signals are easily affected by electromagnetic interference. The lack of spatial resolution caused by these signal amplitudes can cause signal distortion or loss of important information, affecting subsequent signal analysis and processing.

[0007] According to the Nyquist sampling principle, the sampling frequency must be more than twice the frequency of the sampled waveform to accurately restore the sampled waveform. This means that for fast-changing narrow pulse signals, the sampling time interval must be very small.

[0008] In order to solve these problems, the narrow pulse signal usually needs to collect and analyze a large amount of data in a short time, which puts high requirements on the real-time and accuracy of the system. The sampling needs to select an ADC (analog-to-digital converter) chip with high sampling rate and high resolution to ensure processing a large amount of data in a short time, so as to meet the time resolution and spatial resolution requirements of narrow pulse signal acquisition. For the narrow pulse signal with periodicity, the equivalent sampling mode can be used to reconstruct the waveform through multiple triggering and acquisition; for the non-periodic narrow pulse signal, the real-time sampling mode needs to be used to ensure that enough samples are collected in a single triggering event.

[0009] At the same time, in terms of hardware design, reasonable layout and wiring are needed to reduce the influence of noise and interference on the acquisition result; in terms of software design, efficient and stable code needs to be written to realize real-time acquisition, storage and processing of data.

[0010] In summary, the difficulty of narrow pulse current signal acquisition lies in the requirements of high time resolution and high spatial resolution, and the challenges of real-time and accuracy. Practical new type content

[0011] The utility model provides a kind of non-invasive, digital trigger's narrow pulse current signal sampling circuit.

[0012] The technical scheme of the utility model:

[0013] A kind of non-invasive narrow pulse current signal sampling circuit, the circuit includes non-invasive current sensor, integral circuit, amplification and pulse broadening circuit, analog signal filter, main control circuit;The non-invasive current sensor, integral circuit obtains narrow pulse current signal-analog quantity, the magnetic field change around the non-invasive current sensor electromagnetic induction lead, generates induced current, the integral circuit is integrated to induced current;The amplification and pulse broadening circuit amplify and broaden narrow pulse current signal-analog quantity;The analog signal filter filters narrow pulse current signal-analog quantity after amplification and broadening;The main control circuit filters narrow pulse current signal-analog quantity after sampling.

[0014] The above technical scheme is further refined, and the integral circuit is composed of diode, resistance and capacitor;The amplification and pulse broadening circuit is composed of triode and resistance;The main control circuit is MCU.

[0015] The utility model discloses a non -invasive, digital trigger's narrow pulse current signal sampling circuit, the circuit includes integral circuit, amplification and pulse broadening circuit, sampling trigger circuit, analog signal filter, digital filter circuit, main control circuit, the non -invasive current sensor, integral circuit obtains narrow pulse current signal - analog, the non -invasive current sensor electromagnetic induction wire around the magnetic field change, produces induction current, integral circuit integrates induction current,

[0016] Amplification and pulse broadening circuit amplify and broaden narrow pulse current signal - analog, sampling trigger circuit sends trigger signal - digital based on amplified and broadened narrow pulse current signal - analog, analog signal filter filters amplified and broadened narrow pulse current signal - analog, digital filter circuit filters trigger signal - digital, and main control circuit accepts filtered trigger signal - digital, filters narrow pulse current signal - analog and samples.

[0017] The utility model further refines the above technical scheme, and integral circuit is composed of diode, resistance, capacitor, amplification and pulse broadening circuit is composed of triode, resistance, sampling trigger circuit is composed of resistance, triode, digital filter circuit is composed of resistance, capacitor, and main control circuit is MCU.

[0018] The utility model discloses a non -invasive, digital trigger's narrow pulse current signal sampling circuit, the circuit includes integral circuit, amplification and pulse broadening circuit, sampling trigger circuit, analog signal filter, digital filter circuit, main control circuit, the non -invasive current sensor, integral circuit obtains narrow pulse current signal - analog, the non -invasive current sensor electromagnetic induction wire around the magnetic field change, produces induction current, integral circuit integrates induction current, BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is non -invasive, digital trigger's narrow pulse current signal sampling circuit diagram.

[0020] Figure 2 It is non -invasive, digital trigger's narrow pulse current signal sampling circuit principle diagram.

[0021] In the drawing, non -invasive current sensor T1 1, integral circuit 2, amplification and pulse broadening circuit 3, sampling trigger circuit 4, analog signal filter C2 5, digital filter circuit 6, MCU 7. DETAILED DESCRIPTION

[0022] As Figure 1As shown, a non-invasive, digital trigger narrow pulse current signal sampling circuit, non-invasive current sensor T1 1, diode D1, resistor R1, capacitor C1 constitute integral circuit 2, transistor Q1, resistor R2, resistor R3 constitute amplification and pulse stretching circuit 3, resistor R4, resistor R5, resistor R6, transistor Q2 constitute sampling trigger circuit 4, analog signal filter C2 5, resistor R6, capacitor C3 constitute digital filter circuit 6, MCU 7.

[0023] Principle 1:

[0024] The pulse current I flows in the wire, the time is t (P1), the magnetic field around the wire changes, the current sensor T1 generates an induced electromotive force in the coil due to electromagnetic induction, and then generates an induced current Is, which is integrated by R1 and C1. The voltage across C1 after integration is Uc1; At the same time, C1 discharges through R2, and because R2 is relatively large, the discharge period t2 is long, and the pulse signal is stretched (P2). The pulse signal is amplified by Q1 at the same time, (because the current signal is generated during the discharge and signal amplification process, the anti-interference performance is strong) After amplification, the signal is filtered by C2, and the MCU samples it. One end generates a digital signal (P3) as a sampling trigger level and a start and stop signal for sampling. Figure 2 Figure 2 Figure 2

[0025] Principle 2:

[0026] As Figure 1 , the current function in the wire is i(t), and the current sensor T1 will generate a corresponding induced electromotive force e(t). According to Ampere's loop theorem:

[0027] (Formula 1)

[0028] (Formula 2)

[0029] According to formulas 1 and 2:

[0030] (Formula 3)

[0031] Where e is the induced voltage; N is the number of turns; A is the cross-sectional area of the coil; M is the mutual inductance of the coil; μ0 is the relative magnetic permeability of air;

[0032] From formula 3, it can be seen that the measured current and the coil induced voltage are in a differential relationship, and the coil is essentially equivalent to a differential element. In order to accurately reproduce the current waveform, the accurate equivalent circuit model of the sensor head must be established to accurately integrate and restore the induced voltage e(t). ​​​

[0033] As Figure 1 , using R1 and C1 consisting of integral circuit to e(t) integration, C1 end voltage is UC1:

[0034] (Formula 4)

[0035] Assuming the triode amplification β, then C2 output voltage is UC2:

[0036] (Formula 5)

[0037] The pulse width τ after the spread: τ ≈ 2R2*C (determined according to the specific amplification).

[0038] The above, only for the preferred embodiment of the present application, but the scope of the present application is not limited to this, any skilled in the art of the technical personnel in the present application disclosed in the technical range, can easily think of changes or replacement, should be covered in the scope of the present application. Therefore, the scope of the present application should be limited to the scope of protection claimed in the claims.

Claims

1. A non-invasive narrow pulse current signal sampling circuit, characterized by, The circuit comprises: a non-intrusive current sensor for acquiring narrow pulse current signal-analog quantity, an integral circuit, a magnetic field change around an electromagnetic induction wire, a non-intrusive current sensor for generating induced current, and an integral circuit for integrating the induced current; an amplification and pulse widening circuit for amplifying and widening the narrow pulse current signal-analog quantity; an analog signal filter for filtering the narrow pulse current signal-analog quantity after amplification and widening; a main control circuit for filtering and sampling the narrow pulse current signal-analog quantity after filtering.

2. The non-intrusive narrow pulse current signal sampling circuit according to claim 1, wherein the integral circuit is composed of a diode, a resistor, and a capacitor; the amplification and pulse widening circuit is composed of a triode and a resistor; the main control circuit is an MCU.

3. A non-invasive, digitally triggered, narrow pulse current signal sampling circuit, characterized by, The circuit comprises: a non-intrusive current sensor for acquiring narrow pulse current signal-analog quantity, an integral circuit, a magnetic field change around an electromagnetic induction wire, a non-intrusive current sensor for generating induced current, and an integral circuit for integrating the induced current; an amplification and pulse widening circuit for amplifying and widening the narrow pulse current signal-analog quantity; a sampling trigger circuit for sending a trigger signal-digital quantity based on the narrow pulse current signal-analog quantity after amplification and widening; an analog signal filter for filtering the narrow pulse current signal-analog quantity after amplification and widening; a digital filter circuit for filtering the trigger signal-digital quantity; a main control circuit for filtering and sampling the narrow pulse current signal-analog quantity after filtering.

4. The non-intrusive, digital trigger narrow pulse current signal sampling circuit according to claim 3, wherein the integral circuit is composed of a diode, a resistor, and a capacitor; the amplification and pulse widening circuit is composed of a triode and a resistor; the sampling trigger circuit is composed of a resistor and a triode; the digital filter circuit is composed of a resistor and a capacitor; the main control circuit is an MCU.

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