PURPOSE: To provide the digital filter device not requiring high speed arithmetic operation even when an undesired signal component in a filter output is in existence at least a high frequency of an input analog signal.
CONSTITUTION: The filter is provided with an input terminal 101 used to receive an analog signal, an A/D converter means 102 sampling the analog signal at a frequency being twice or over of the highest frequency and converting the signal into a digital signal, a storage means 103 storing N sets of digital data outputted from the A/D converter means 102, an acyclic digital filter whose length of impulse response is N which receives an output of the storage means 103 to implement the arithmetic operation and a control means 108, and after the A/D converter means 102 samples N-sets of data and outputs an output signal from the digital filter based on the N-sets of data for each time below a period with respect to a frequency twice the highest frequency of the output signal.
YOSHIMOTO MITSUFUMI
HAMA KOJI
KOSAKA AKIO
TOKYO SANYO ELECTRIC CO