| 摘要 |
PURPOSE:To reduce digital disturbance without increasing the number of bits, by providing a nonlinear circuit, which operates as an LPF in response to only an extremely samll variation, on a transmission line for the D/A-converted picture signal of a digitized picture signal. CONSTITUTION:An analog picture signal (a), obtained by performing the D-A conversion 1 of a digitized picture signal, is passed through a transistor TR2, a resistance 3, and a capacitor 4 to obtain a signal (b) having the high freuqnency range emphasized, and the signal (b) is supplied to the base of a TR6. In response to large variations of the signal (b), either one of diodes 9 and 10 conducts to supply the signal (b) to an output as it is. In response to small variations of the signal (b), neither diode 9 nor 10 conducts and the signal (b) appearing at the emitter of the TR6 is outputted through an inductance 7. The inductance 7 and a resistance 8 form an LPF, through which only small level variations of the signal (b) pass to eliminate the high frequency component of the small variation part of the original signal (a). Consequently, it is restored to a signal (c) having gentle slanting characteristics, thereby reducing disturbance due to an quantization error in digitization. |
