| 摘要 |
PURPOSE:To decrease the cost by combining a short ferrite bar antenna and a tuning transformer so as to form a band selecting section. CONSTITUTION:An inductance of a ferrite antenna coil L3 is tuned to the 1st band signal and an inductance of a tuning transformer L4 is tuned to the 2nd band signal having a frequency lower than that of the 1st band when the ferrite antenna coil L3 is connected to a tap (b). In taking the 1st band as a medium wave and the 2nd band as a long wave, the inductance of the ferrite antenna coil L3 is 280muH and that of the tuning transformer L4 is about 8mH. The tracking is adjusted for the medium wave by the position of the L3 and a trimmer capacitor C3 and for the long wave by the core of L4 and a trimmer capacitor C4. |
