11种数字滤波函数（Eleven digital filtering functions）.docVIP

11种数字滤波函数（Eleven digital filtering functions） The principle and realization of 11 kinds of classical software filtering 1. Limited filter method (also known as program judgment filtering method) A. methods: According to experience, the maximum deviation value (set to A) is determined by two sampling permits. Each time a new value is detected: If this value is not the same as the last value, the value is valid If the difference between this value and the last value is A, this value will not be valid, and the value will be replaced by the previous value B. Advantages: Can overcome the impulsive interference caused by accidental factors C and disadvantages You cant suppress that kind of periodic interference Poor smoothness 2. Median filtering method A, method: N times continuous sampling (N takes odd number) Arrange N subsamples by size Take the intermediate value for this valid value B. Advantages: Can effectively overcome the disturbance caused by accidental factors The measured parameters of temperature and liquid level are well filtered C, disadvantages: It is not suitable for fast changing parameters such as flow rate and speed 3. Arithmetic mean filtering method A. methods: N sample values are continuously taken to perform arithmetic arithmetic Higher N value: high signal smoothness, but lower sensitivity N value: low signal smoothness, but high sensitivity N value selection: general flow, N = 12; Pressure: N = 4 B. Advantages: It is suitable for filtering the signal with random interference The signal is characterized by an average signal that moves up and down near a numerical range C. Disadvantages: Real time control for slow measurement or fast data calculation is not applicable Its a waste of RAM 4. Recursive average filtering method (also known as sliding average filtering method) A. methods: Im going to take N sample values as a queue The length of the queue is fixed to N Each time a new data is sampled into the team tail, and discard the first data of t