| 摘要 |
PURPOSE:To make it possible to practice economy from conventionally-two kinds of circuit to one kind of circuit, by extracting a low-frequency compoent by removing a carrier from an input signal by using a matching filter for a split-phase signal with a phase synchronous circuit. CONSTITUTION:A carrier-frequency signal applied to terminal A is integrated from the start to the end of one cycle of the carrier by matching filter 5 which regards one cycle of the carrier as a split-phase (SP) signal of one bit. At the end of the cycle, the integral value is sampled and outputted. This output has the unneeded high- frequency component removed by LPF6 and is decoded by matching filter 7 for a SP signal. Matching filters 5 and 7 mentioned above may use integral discharge type one or be composed of an A/D converter and an up-down counter. Consequently, needed two kinds of circuits can be reduced to one, so that the constitution can be simplified. |
