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Title:
FREQUENCY MODULATION BAND PASS FILTER
Document Type and Number:
Japanese Patent JPS58220512
Kind Code:
A
Abstract:

PURPOSE: To constitute so that input impedance has both terminals of 75Ω and 300Ω, by grounding the middle point of a primary coil, and connecting each capacitor having an equal capacity between both ends of the primary coil and a ground, in parallel to the primary coil divided into two.

CONSTITUTION: Primary coils 1, 1' and capacitors 3, 3' have equal number of windings and capacity, respectively, therefore, when output voltage generated between output terminals 8, 9 in case of applying input voltage V1 to input terminals 5, 6 is denoted as V0, the output voltage V0 is generated between the output terminals 8, 9 even if the input voltage V1 is applied between the input terminals 6, 7. Also, when input voltage of 2V1 is applied between the input terminals 5, 7, the output voltage V0 is generated between the output terminals 8, 9. Accordingly, electric power in case when the input voltage V1 is applied between the input terminals 5, 6 is equal to electric power in case when the input voltage 2V1 is applied between the input terminals 5, 7, therefore, input impedance between the input terminals 5, 7 is proportional to a square of the input voltage, and an antenna inputting circuit provided with a 75Ω unbalanced type and a 300Ω balanced type is obtained without using a balun transformer.


Inventors:
Umemoto, Katsuhiko
Application Number:
JP1982000102972
Publication Date:
December 22, 1983
Filing Date:
June 17, 1982
Export Citation:
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Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H03H7/09; H03H7/42; H04B1/10; (IPC1-7): H03H7/09



 
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