| 摘要 |
A circuit arrangement with an adjustable amplitude-frequency response between an input signal terminal and an output signal terminal can be changed over simply between a fourth-order high-pass or low-pass characteristic and a second-order all-pass characteristic. The circuit includes first and third filters each with a filter function F, a second filter with a filter function G, a plurality of coefficient sections and first and second summing stages all coupled together so that the circuit has a transfer function A between the input signal terminal and the output signal terminal with a component complying with A=(C+(1-C)xF-2xCxG)x(C(1-C)xF),whereF=FN=1/(1+axs+bxs2)orF=FH=bxs2/(1+axs+bxs2)represents a first filter function with a second-order high-pass or a low-pass characteristic andG=axs/(1+axs+bxs2)represents a second filter function, and where a, b are constant real factors, C is a real factor whose magnitude is selectable between 0 and 1 inclusive, and s is the product of the imaginary unit and the angular frequency ( omega ).
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