| 摘要 |
An improved channel selector for a television receiver includes a metal semiconductor field effect transistor, i.e. MESFET mixer in combination with an acoustic surface wave device filter. The MESFET mixer simultaneously receives a plurality of channels and mixing signals of a selectable frequency, and in response thereto frequency shifts selectable channels to a predetermined center frequency. The MESFET mixer has almost perfect square law characteristics, and accordingly introduces extremely small distortion into the system. The acoustic surface wave device filter has an input coupled to the output of the MESFET mixer. The surface wave device filter provides essentially all of the channel selectivity of the receiver.
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