引言目前所有调幅收音机或调谐器的设计,几乎都采用铁氧体天线以及/或者具有一个或二个单独的调谐射频电路的调谐射频级。基本上这是老式五管机的稍许改进。由于这个原因,几乎所有涉及调幅收音机设计的文献,都是在大型电子管式收音机普及时发表的。当收音机必须具有大于4千赫的音频响应时,这种结构是不能满意的,因而需寻 INTRODUCTION At present, almost all AM receivers or tuners are designed with ferrite antennas and / or tuned RF stages with one or two separate tuned RF circuits. Basically this is a slight improvement on the old five-tube machine. For this reason, almost all the literature on the design of AM radios is published at the time of popularization of large-scale tube radios. When the radio must have an audio response greater than 4 kHz, this structure is unsatisfactory and therefore needs to be searched