阅读说明：本技术 基于stm32单片机的自适应数字滤波器设计方法 (Self-adaptive digital filter design method based on stm32 single chip microcomputer ) 是由 吴昊男 韩依伦 瞿祝 于 2019-08-16 设计创作，主要内容包括：本发明提供了一种基于stm32单片机的自适应数字滤波器设计方法。所述的基于stm32单片机的自适应数字滤波器设计方法包括根据实际应用场景动态调整采样率、单片机存储系列滤波器系数组、DA外接模拟滤波器恢复原有效信号,该方法可有效进行无用信号滤除,合成信号的分离,具有相应速度快、系统稳定性高、实现方法简易可行的特点。(The invention provides a design method of an adaptive digital filter based on a stm32 single chip microcomputer. The design method of the self-adaptive digital filter based on the stm32 single chip microcomputer comprises the steps of dynamically adjusting the sampling rate according to an actual application scene, storing a series filter coefficient group by the single chip microcomputer, and externally connecting a DA analog filter to recover an effective signal.)

1. A design method of an adaptive digital filter based on a stm32 single chip microcomputer is characterized by comprising the following steps: including accurate equal precision frequency measurement methods to determine the frequency components of the noise.

2. The design method of the adaptive digital filter based on the stm32 single-chip microcomputer according to claim 1, wherein the method comprises the following steps: including methods of configuring external triggers for flexible sample rate setting to dynamically use digital filters.

3. The design method of the adaptive digital filter based on the stm32 single-chip microcomputer according to claim 1, wherein the method comprises the following steps: including the setting of system frameworks and program flows.

Technical Field

The invention belongs to the technical field of signal processing, and particularly relates to a design method of an adaptive digital filter based on a stm32 single-chip microcomputer.

Background

The filter design is indispensable in the field of signal processing, and the filter can effectively solve the problems of separation after signal synthesis and noise pollution of signals; the development of the analog filter is limited by electronic components, and the design of the digital filter is limited by sampling rate and algorithm; in the complex signal processing process, a self-adaptive dynamically-adjusted filter is urgently needed, the effect of an equivalent analog filter can be enhanced by combining the assistance of an analog circuit, certain intelligence is achieved, and the subsequent algorithm optimization and the complexity of the analog circuit can be greatly simplified in the signal processing process.

Disclosure of Invention

The invention aims to provide a design method of an adaptive digital filter based on a stm32 single chip microcomputer.

Detailed Description

If the known noise frequency component is removed, a band elimination digital filter is built in the program; if signal separation is performed, a bandpass digital filter is built in the program.

Using equipment: precision DDS (stable, precise to 1HZ or better), precision comparator, STM32 single chip microcomputer (ADC, timer, GPIO, etc.)

The system flow is as follows: AD acquisition-STM 32 performs iir filter processing-DA output-analog filter to remove extraneous components.

The specific process is as follows: the mixed signal is collected through the single chip ADC, the sampling rate is directly controlled by the output of the single chip GPIO to configure an external precise DDS or an oscillation source, the signal is shaped into 0-3.3V square waves through the precise comparator and used as a stable trigger source of the single chip ADC, the DDS output frequency can be dynamically and flexibly adjusted, the analog sampling rate can be flexibly controlled, and the on-off of a set frequency band can be easily realized corresponding to a digital domain. The sampling rate setting is related to the filtered target frequency component and the digital sampling rate of the digital filter, and can be dynamically adjusted according to requirements.

(example) designing a digital filter with a sampling rate of 100000, a filtered component of 10000, and a stop band filter with a stop band of 9999-10001; when the noise component is 50000HZ, the signal component is less than 250000HZ, the sampling rate can be adjusted to 500000HZ, so that the 50000HZ frequency component can be accurately filtered, and all frequency components except the 49995HZ to 50005HZ components are not influenced; the DA output part can be connected to a 250000HZ active analog filter, the system can well filter noise components, and the system is high in corresponding speed and high in filtering accuracy.

The program built-in digital filter can be generated by FDAtools of matlab, the normalized sampling rate and the passband and stopband characteristics of the digital filter can be set, and the digital filter can be used as a coefficient of an IIR function in stm32 after configuration, so that the function of the digital filter can be realized. And the self-adaptive filter with any frequency can be flexibly realized by matching with the dynamic adjustment scheme, an external analog filter and other circuit aids.

In summary, the applied digital filter can be adjusted comprehensively according to the actual upper limit of the sampling rate, the filtered target component and the effective target component, a series of filter coefficients are stored in the single chip microcomputer, and dynamic selection is performed according to the actual application condition, so that the analog filter with any precision can be flexibly realized.