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Title:
VARIABLE TUNING FILTER CONTROL METHOD AND RECEIVER USING THE METHOD
Document Type and Number:
Japanese Patent JP2002026751
Kind Code:
A
Abstract:

To provide a receiver that can apply frequency tuning control to a variable tuning filter, by utilizing a frequency control signal of a PLL local oscillation circuit.

An amplifier 1 amplifies a received signal 101 up to a desired amplitude. The variable tuning filter 2, that is controlled by a voltage control signal 110 applies band limiting to the received signal 101. A mixer 3 applies frequency conversion to the received signal 101. An intermediate frequency amplifier 4 amplifies the output of the mixer 3, until it has a desired amplitude. A filter 5 eliminates unwanted waves which lie outside of the band. A demodulation section 6 demodulates an output of the filter 5. A local oscillation section 7 provides the output of a local oscillation signal 104, on the basis of the frequency control signal 106. A digital/analog converter 8 supplies the voltage control signal 110, selected from a preset control voltage corresponding to the frequency control signal 106, to the variable tuning filter 2. A control section 9 outputs the frequency control signal 106, on the basis of an external control signal 105 that designates the frequency of the received signal 101.


Inventors:
YOKOTA YOSHIMASA
Application Number:
JP2000201181A
Publication Date:
January 25, 2002
Filing Date:
July 03, 2000
Export Citation:
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Assignee:
NEC WIRELESS NETWORKS LTD
International Classes:
H03H17/00; H03H17/02; H04B1/10; H04L27/148; H04L27/22; (IPC1-7): H04B1/10; H03H17/00; H03H17/02; H04L27/148; H04L27/22
Attorney, Agent or Firm:
Naoki Kyomoto (2 outside)