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

摘要

This invention relates to an analog amplifier and an analog filter for amplifying the analog signal , and in particular gain block relates to a variable gain amplifier and a variable cut-off frequency device and method for simply controlling the gain and cut-off frequency in a filter capable of changing a frequency . Variable resistor of the present invention comprises a plurality of resistance segments in the interior of the variable resistor , in the case of sorting a plurality of candidates for the variable resistor a resistance value which may have in order of size , the plurality of resistance value candidates are the geometric sequence features that make it . ;