PURPOSE: To obtain a filter with an optional characteristic by providing a switched capacitor equivalent resistance circuit 1 capacitor circuit, a connection analog switch, a clock signal circuit and a rewritable nonvolatile memory.
CONSTITUTION: Clock signals fS1∼fSn of a prescribed frequency are given to switched capacitor equivalent resistor circuits R1∼R5 via a clock signal circuit 10 by switching frequency changeover command informations S0 stored in an EEPROM 200. In such a case, the content of storage of the EEPROM 200, that is, the content of the switching frequency changeover command information S0 is rewritten to revise the switched capacitor equivalent resistance optionally, then the characteristic change and trimming are made possible accordingly. Then the user can modify the characteristic and the characteristic change and trimming are attained by rewriting the storage data in the EEPROM externally.
KIDO MITSUYASU
KAWAI TADAO
KUDO HIROYUKI
| JPS57203315A | 1982-12-13 | |||
| JPS61177810A | 1986-08-09 |