THE VARIABLE GAIN AMPLIFIER AND THE VARIABLE CUTOFF FREQUENCY FILTER WHICH USE LINEAR-IN-DB PROGRAMABLE RESISTORS METHOD THEREOF

摘要

The the present invention is an analog amplifier, and relates to an analog filter, in particular, gain and cut-off frequency in the variable gain amplifier and a variable cut-off frequency filter capable of changing the gain and cut-off frequency for amplifying the analog signal to an apparatus and method that can be simply controlled. Variable resistor of the present invention when comprising a plurality of resistor segments in the interior of the variable resistor, arranged a plurality of resistance value candidates that has the variable resistor can have in order of size, the plurality of resistance value candidates a geometric progression characterized in that the make up. ;