| 摘要 |
PURPOSE:To easily and accurately attain the desired tuning control by storing a control voltage characteristic of a frequency tuning circuit into a pROM. CONSTITUTION:The characteristic of a tuning frequency fo of a filter and a VCO being components of the frequency tuning circuit together with a varactor diode and the characteristic of a control voltage VB of the varactor diode are measured, the control voltage VB is digitized by an analog/digital converter, the frequency or channel number corresponding to a digital code are used as an address and the data is stored in a programmable ROM 15. In operating the titled circuit, when a desired frequency or a desired channel is designated by inputting a number setting signal 18 next, a data taking a number setting input in the pROM 15 as an address, that is, a digital control voltage DVB is outputted and fed to a next-stage digital/analog converter 16, from which an analog control voltage VB is generated and inputted to a frequency tuning circuit 17, whose tuning frequency is controlled.
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