STATE VARIABLE TYPE BAND-PASS FILTER

摘要

PURPOSE:To set independently the center angular frequency, sharpness and pass band gain by providing 4-stage of operational amplifiers and acting the 1st and 2nd operational amplifiers like inverse amplifiers and acting the 3rd and 4th operational amplifiers like integration devices respectively. CONSTITUTION:The 4-stage of operational amplifiers OP11-OP14 are provided in series, the amplifiers OP11, OP12 constitute inverse amplifiers respectively and the amplifiers OP13, OP14 constitute integration devices respectively. The product between an input resistor R17 and a capacitor C17 is selected equal to the product between an input resistor R18 and a capacitor C12, an input resistor R11, a feedback resistor R12 and the resistor R17, and the product between the resistor R17 and the capacitor C11 are made variable. Thus, the center angular frequency omega0, the sharpness Q and the pass band gain H are variable independently and the degree of freedom to them is attained and the titled filter copes with many systems.