PURPOSE: To reduce a variable range of a tuning voltage of a VHF circuit especially with respect to the tuner circuit employing a varactor diode for a tuning circuit.
CONSTITUTION: A tuning voltage is applied from a terminal 3 to a UHF circuit as it is, the tuning voltage is divided by resistors 14,15 and the divided voltage is fed to varactor diodes 9-12 of a VHF circuit. Thus, the tuning voltage of the VHF circuit is biased to 0V position to reduce a variable tuning range. Thus, the variable tuning voltage is adjusted by dividing the tuning voltage fed to each varactor diode of the VHF circuit by resistors and the tuner circuit is operated stably. The inductance of the coil is reduced by increasing the tuning capacity of the tuning circuit to make the tuner circuit small.
JP4425711 | Antenna control method and wireless transmitter / receiver |
JP3316663 | [Title of Invention] High-sensitivity wireless receiver |
WO/2011/052658 | DIGITAL TUNER |
TAMARU KENJI