| 摘要 |
PURPOSE:To improve the operability by providing a pre-stage receiving means formed with a single mixer to plural receiving signals so as to use a receiving circuit in common thereby eliminating the need for installation of plural receivers. CONSTITUTION:An antenna 1, an RF unit 2 and a mixer 3 constitute a pre-stage reception circuit. The pre-stage reception circuit inputs a local signal fL to the local side of the mixer 3, converts plural desired signals into plural intermediate frequencies and outputs to the 1st the 2nd receiving circuits of the post stage. The 1st and 2nd receiving circuits of the post-stage consist of an intermediate frequency circuit 4, its sound circuit, an intermediate frequency circuit 4' and its sound circuit. Since the pre-stage reception circuit is used in common in this way, even if plural receiving signals are intercepted, it is not required to install plural receivers and the operability is improved.
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