| 摘要 |
The circuit generates the reference level prevented from being varied by detecting peak level with a differential amplifier to improve the characteristics of teletext data abstracting. The circuit includes a differential amplifier section (11a) for detecting positive signal from input signal (Vin), an emitter follower outputting sect. (11b) for negatively feeding back level stabilizing output (VL) and peak level output (VH) to differential amplifier sect. (11a,12a), and an averaging circuit (13) for generating the reference level signal (Vref) of teletext data abstracting.
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