| 摘要 |
PURPOSE:To perform time constant switching of optional four kinds by providing a feedback circuit consisting of four resistors and a capacitor connected in series between output of a feedback type amplifier circuit and a feedback point and controlling connection of four resistors using two switching elements. CONSTITUTION:A feedback circuit 10 is connected between the output terminal 3 of a feedback type amplifier circuit 2. The circuit 10 is made by connecting resistors R5, R6, R7, R8 and a capacitor 9 directly. Further, a switching element 11 is connected to both ends of series connection of R5 and R6. When using an ordinary tape at normal speed, both elements 11, 12 are made off, and when using a high performance tape at normal speed, the element 11 is made on and the element 12 is made off. When using an ordinary tape at high speed, the element 11 is made off and the element 12 is made on. When using a high- performance tape at high speed, both elements 11, 12 are made on. Thus, four kinds of time constant switching can be made.
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