| 摘要 |
The clock has an input circuit selectively tuned to the frequency of the transmitter and supplied from the 220 volt mains network. The input circuit uses an LC bandpass filter with a selection precision of + or-1KHz at -3db. Pref. the input circuit has two input modes (11,12) to which the mains cable is soldered, each coupled to a capacitor (13,14) with a capacitance of 4.7nF. The capacitors (13,14) are coupled at the opposite side by a coil (16) which forms part of a variable inductive coupling, the other coil (18) of which is connected in series with a tuning coil (19) and a capacitor (23). The output modes (21,22) are coupled to either side of this capacitor. |
