METHOD FOR IMPROVING FILTERING CHARACTERISTICS OF LOW PASS FILTER

PURPOSE: A method for improving a filtering characteristics of a low pass filter is provided, which obtains a desired frequency cutting characteristics with a low order low pass filter by reducing an overshoot around a cutoff frequency and also improves a cutoff band characteristics as to the low pass filter. CONSTITUTION: According to the method, a low pass filter is constituted by installing a notch filter between the first low pass filter and the second low pass filter. And if input signal is filtered by the first low pass filter, it shows a filtering characteristics curve of Figure 7-(A). And the signal filtered through the first low pass filter is filtered by the notch filter, it shows a filtering characteristics curve of Figure 7-(B). And the signal filtered by the notch filter is filtered by the second low pass filter, it shows a filtering characteristics curve of Figure 7-(C).