
n. [电讯] 超外差式收音机
This paper first discusses the instinct disadvantage of a superheterodyne receiver, which is that it has more spurious response.
本文首先指出了超外差接收机的固有缺点,即它有更多的虚假响应。
In this paper, a superheterodyne receiver is taken as an example to illustrate the characteristic and effect of virtual experiment teaching.
并以超外差接收机的工作原理为例,说明了虚拟实验教学的特点和作用。
According to the research and analysis of structure in several receivers, this paper brings forward a solution based on the superheterodyne receiver.
在分析研究各种接收机结构的基础上,论文提出了基于超外差接收机的解决方案。
The system uses the emitter to send ultra high frequency signals after coding with signal coder and the secondary superheterodyne mixing receiver to accept the moving target signals.
系统中发射器采用编码器编码后发送超高频信号,接收器采用二次混频型超外差式接收移动目标信号。
Aiming at request of private mobile radio, technology requirement of base station receiver based on TETRA protocol is analyzed, and two intermediate frequency superheterodyne structure is selected.
针对专用移动移动通信对接收机的要求,分析了TETRA协议中基站接收机技术指标和选择双中频超外差接收机方案。
Finally, it points out that, as far as wide open receiver is concerned, to suppress or reduce the spurious response is one of the most important tasks in designing a superheterodyne receiver.
最后指出对于宽开接收机而言,抑制或减少虚假响应是设计超外差接收机的重要任务之一。
超外差接收机(Superheterodyne Receiver) 是一种广泛应用于无线电通信(如广播、电视、雷达)的高性能接收机架构。其核心原理是通过变频技术,将接收到的高频射频信号转换为固定的、较低的中频信号,再进行放大和解调,从而显著提高接收机的灵敏度、选择性和稳定性。
$$ V{out} = k times V{RF} times V{LO} $$
其中 $$V{RF}$$ 是射频信号,$$V_{LO}$$是本振信号,$$k$$是混频系数。
超外差架构由美国工程师埃德温·阿姆斯特朗于1918年发明并申请专利(专利号US1342885A),彻底革新了无线电接收技术。在此之前,接收机(如再生式、直放式)在高频段难以同时获得高增益和高选择性。超外差原理因其卓越性能,至今仍是几乎所有现代无线接收设备(收音机、电视机、手机、Wi-Fi路由器、雷达接收机、卫星接收机等)的基础架构。
参考资料:
超外差接收机(superheterodyne receiver)是一种广泛应用于无线电通信的核心技术,其核心原理是通过频率转换实现高效信号处理。以下是详细解释:
超外差接收机是一种将接收信号与本机振荡器(LO)产生的频率混合,生成固定中频(IF)信号的无线电接收装置。这种设计由Edwin Armstrong于1918年发明,至今仍是主流技术。主要模块包括:
关键步骤为:
存在镜像频率干扰问题,即:$$ f{image} = f{LO} pm f_{IF} $$ 需通过预选滤波器抑制干扰
广泛应用于广播收音机(AM/FM)、电视、雷达、卫星通信等场景,现代智能手机的射频前端也采用改进型超外差架构
该技术通过频率转换的创新设计,解决了早期收音机多频段接收的难题,成为无线电发展史上的里程碑。
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