VHF TUNER
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专利名称：VHF TUNER
发明人：OOSAWA HIROSHI 申请号：JP2074581
申请日：19810213
公开号：JPS57135529A
公开日：
19820821
专利内容由知识产权出版社提供
摘要：PURPOSE:To set the value of a feedback resistance relatively small by connecting the feedback resistance to the cathode side of a switching diode for band switching. CONSTITUTION:While a switch 22 allows a DC voltage +B to be developed at an output terminal 23, a tuning circuit 36 is placed in a low-band reception state. The voltage +B and bias resistances 27, 28, 35, and 34 set a local oscillation transistor (TR)25 for a relatively small bias. When the voltage +B is developed at an output terminal, a switching diode 30 for band switching turns on to ground a point B in terms of high frequency, so the circuit 36 is set in a high-band reception state. The DC voltage at the terminal 24, on the other hand, is applied to a TR25 through a switching diode 29. A voltage developed across a feedback resistance 34 is also applied to the TR25. Thus, the bias to the TR25 is set great. Further, the resistance 34 is provided on the cathode side of the diode 30, so that its required value may be relatively small.
申请人：SANYO DENKI KK
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