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Title:
RECEIVING BAND CHANGEOVER DEVICE
Document Type and Number:
Japanese Patent JPS59196618
Kind Code:
A
Abstract:

PURPOSE: To simplify the circuit by using a variable capacitance and one switch so as to change over two bands.

CONSTITUTION: When a switching transistor (TR) 21 is turned on and a tuning coil 18 is short-circuited in receiving the MW, a resonance circuit is constituted by a tuning coil 13 and a variable capacitance tuning element 15 so as to receive the MW. In receiving the LW, the switching TR21 is turned off so as to form the resonance circuit with the tuning coils 13, 18 and the variable capacitance tuning element 15, thereby tuning the resonance circuit to the LW band by using two antenna coils 11, 17. In selecting the winding ratio of the tuning coils 19, 18 to a value of nearly 1:2, the mtching with a loop antenna 10 is excellently taken comparatively and a signal is received with high sensitivity.


Inventors:
Serizawa, Masabumi
Taniguchi, Kazuo
Application Number:
JP1982000184873
Publication Date:
November 08, 1984
Filing Date:
October 20, 1982
Export Citation:
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Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H03J5/24; (IPC1-7): H03J5/24



 
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