Production manner null of the tuning circuit which forms the high frequency tuning circuit and its tuning circuit of the radio set

摘要

PROBLEM TO BE SOLVED: To improve the degree of designing freedom of a radio receiver by making each tuning circuit constructing a high frequency channel selection circuit into a single block. ;SOLUTION: The variable capacitance diodes are sorted for every necessary rank and the fixed capacitors are sorted for every necessary capacitance value respectively. Then the fixed capacitors corresponding to the ranks of variable capacitance diodes are selected for every tuning circuit. The variable capacitance diodes, the fixed capacitors selected according to the ranks of variable capacitance and the coils are connected together. Thus a block of a tuning circuit is formed. As a result, the capacitance variable ratio that is set by every tuning circuit is secured in a common tuning voltage range. Then the inductance of every tuning circuit is controlled at a common tuning voltage level, so that no tracking error is caused. Therefore, the tuning voltage range can cover the range of the receiving bands.;COPYRIGHT: (C)1997,JPO