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Patent Searching and Data


Title:
BAND-PASS FILTER CIRCUIT
Document Type and Number:
Japanese Patent JPS59204308
Kind Code:
A
Abstract:

PURPOSE: To observe and adjust the characteristics of a filter almost in a package state by providing a multistage BPF, varying means which vary the reactance element of the BPF, and control voltage generation part at the front stage part of a receiver.

CONSTITUTION: When a channel is set manually from a channel switch 7 and when a channel specifying signal is inputted directly to a control part 25 from a base station side, channel control data is outputted to a local oscillator 5 to set the local oscillator 5 to a desired frequency, and the control voltage generation part 30 of the BPF21 outputs a control voltage corresponding to the channel number. This output voltage is determined while capacity variation of a varicap diode is considered, and outputted to the BPF21. This voltage is applied to varicap diodes 35 and 36 to vary their capacities, setting the BPF21 almost to the frequency of the specified channel. Simultaneously, the frequency of the trailing stage BPF22 is also varied by a varicap diode provided to the BPF22 as well as the front-stage BPF21.


Inventors:
Takahashi, Masao
Iizuka, Shogo
Yamada, Jun
Shimizu, Satoshi
Application Number:
JP1983000079564
Publication Date:
November 19, 1984
Filing Date:
May 06, 1983
Export Citation:
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Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H03H7/01; H03J3/18; (IPC1-7): H03H7/01