| 摘要 |
PURPOSE: An RF tuning circuit of a television tuner is provided to reduce the number of components constructing the television tuner so as to minimize the size of the television tuner. CONSTITUTION: An RF tuning circuit(100) of a television tuner includes an input tuning unit(110) and a tuning unit(120) that respectively form channel select circuits(111,121). The channel select circuit of the input tuning unit is constructed in a manner that a coil(L4) and a condenser(C8) are serially connected to a condenser(C7) and a coil(L3) connected in parallel with each other and a plurality of condensers(C9,C10) and variable capacitance diodes(VD1,VD2) are connected to the condenser connected in parallel with the coil. The channel select circuit of the tuning unit is constructed in such a manner that a coil(L8) is connected in parallel with a condenser(C13), a variable capacitance diode(VD3), a coil(L7) and a condenser(C15) serially connected to a condenser line(C12) and the serially connected coil is connected to a coil(L6) connected in parallel with the condenser line.
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