| 摘要 |
PURPOSE:To produce a tuning voltage corresponding to a desired channel by applying operation and correction based on the standard data in a ROM and bit information of a switch circuit to which a data corresponding to a variation of a tuning circuit of each tuner is set at the outside of a microcomputer. CONSTITUTION:A value of a digital memory 16 is read at channel selection normally and a tuning voltage BTRF of a desired channel is outputted to an input stage tuning filter 5 through a D/A converter 18 based on the said value. When the value in the digital memory 16 is vanished, the random data inserted in a region of the digital memory 16 is dissident with the built-in data in the ROM. In this case, a microcomputer 17 inputs the bit information selected by switch circuits 31-a, 31-b set externally from a port (a). The bit information corresponding to the desired channel is calculated based on the data and the standard data built in the ROM, the result is D/A-converted (18) and given to a tuning voltage input terminal 19.
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