Digital slide average low-pass filter and filtering method thereof

The invention relates to a digital slide average low-pass filter and a filtering method thereof. The filter comprises a digital filter. The digital filter comprises an A/D converting unit, a first calculation unit, a second calculation unit, a first storage unit and a second storage unit. The A/D converting unit converses a sampling analog signal into a digital signal and send the digital signal to the first calculation unit. The first storage unit stores data cumulative sum output by the first calculation unit. The second storage unit stores a digital filter output value output by the first calculation unit. The first calculation unit reads the data of the first storage unit and the second storage unit and calculates the data cumulative value of the current cycle. The second calculation unit receives the data sent by the first calculation unit and updates and stores the digital filter output value to the second storage unit. According to the invention, a traditional filtering method heavily relying on the memory space of a chip is optimized to the filtering method simply needing two storage units, so that the relying degree of the method on system resources is greatly reduced.