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Patent Searching and Data

Document Type and Number:
Japanese Patent JPH05284050
Kind Code:

PURPOSE: To provide the tuner circuit having high jamming excluding ability against jamming signals lower than a desired frequency band by forming a variable voltage trap circuit at a point coupled from an inter-step tuner circuit to the input side of a mixer circuit.

CONSTITUTION: Since the joining capacity of variable capacity diodes 10 and 11 in an inter-step tuner circuit 2 is changed corresponding to a tuning voltage supplied from a terminal 12, the stepwise tuner circuit 2 is tuned to received signals. Concerning a local oscillation circuit 4, the resonance frequency is changed, the frequency of local oscillated signals is turned to a prescribed value, and those signals are inputted to a mixer circuit 3. Thus, the inputted received signals are amplified by a high frequency amplifier circuit 1, band- selected by the inter-step tuner circuit 2 and inputted to the mixer circuit 3. In the mixer circuit 3, the local oscillated signals outputted from the local oscillation circuit 4 and the received signals are mixed, and intermediate frequency signals 5 are generated. The tuning voltage supplied from the terminal 12 is supplied from the inter-step tuner circuit 2 to a coupling capacitor 9 at a gap to the mixer circuit 3, and the joining capacity is changed.

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Masumi Iwamura
Application Number:
Publication Date:
October 29, 1993
Filing Date:
April 06, 1992
Export Citation:
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International Classes:
H04B1/10; H04N5/44; (IPC1-7): H04B1/10; H04N5/44
Attorney, Agent or Firm:
Ogawa Katsuo