| 摘要 |
An input and supply circuit for a filter, specifically centralized remote control receiver, comprising : - a first and a second input terminals (1, 2) receiving an input a.c. signal to be filtered, the energy of which is partially used for supplying the filter (30), - a rectifier circuit (10) having two primary terminals (11, 12) connected to the input terminals (1, 2) and two secondary terminals (13, 14) for the rectified current which are connected to a first (33) and a second (34) supply terminals of the filter (30), respectively, and - a sampling circuit (20) connected to the input terminals (1, 2) and to a first (31) and a second (32) injection terminals of the filter (30) to provide the latter with a signal to be filtered having the same useful spectral characteristics as the input signal, wherein the sampling circuit comprises an electrical link between the first input terminal (1) and the first injection terminal (31) of the filter (30) and a voltage regulator (27) connected to the secondary terminals (13, 14) of the rectifier circuit (10) and providing a stable voltage (U0 ) between the second supply (34) and injection (32) terminals of the filter (30), which circuit is characterized in that the sampling circuit (20) comprises a current mirror (25) connected to the electrical link joining the first input terminal (1) with the first injection terminal (31), to the second input terminal (2) and to the second supply terminal (34) of the filter (30) in order to derive from said electrical link a current (12) the a.c. component of which is equal to that of the current (IS2) flowing across the second input terminal (2) and the second supply terminal (34) of the filter (30). |
