高频课程设计—混频器

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1、 I 通信电子线路课程设计说明书通信电子线路课程设计说明书 混频器 院 、 部： 电气与信息工程学院 2 0 1 4 年1 2 月 II 摘 要 模拟相乘器的主要技术指标是工作象限、线性度和馈通度。工作象限是指容 许输入变量的符号范围。只容许 ux 和 uy 均为正值的相乘器称为一象限的,而容 许 ux 和 uy 都可以取正、负值的则称为四象限的。线性度是指相乘器的输出电压 uO与输入电压ux(或uy)成线性的程度。 馈通度是指两个输入信号中一个为零时， 另一个在输出端输出的大小。 混频是将载波为高频的已调信号，不失真地变换为载波为中间的已调信号。 在通信接收机中, 混频电路的作用在于将不同载

2、频的高频已调波信号变换为同 一个固定载频(一般称为中频)的高频已调波信号, 而保持其调制规律不变。 例如, 在超外差式广播接收机中, 把载频位于 535 kHz1605kHz 中波波段各电台的普 通调幅信号变换为中频为 465kHz 的普通调幅信号, 把载频位于 88 MHz 10.8MHz的各调频台信号变换为中频为10.7MHz的调频信号, 把载频位于四十几 兆赫至近千兆赫频段内各电视台信号变换为中频为 38 MHz 的视频信号。由于设 计和制作增益高, 选择性好, 工作频率较原载频低的固定中频放大器比较容易, 所以采用混频方式可大大提高接收机的性能。此设计就是利用仿真软件，采用模 拟相乘器

3、实现混频电路的。 关键词：模拟相乘器；混频电路 III ABSTRACT The mixer in communication engineering and radio technology, application is very extensive, in modulation system, the input of baseband signal are throughfrequency conversion into a high frequency modulated signal. In the demodulation process, the received modula

4、ted high frequency signal afterfrequency conversion, into intermediate frequency signals corresponding to.Especially in the superheterodyne receiver, mixer is widely used, such as AMradio receiver will be amplitude modulated signal 535KHZ- a 1605KHZ to become 465KHZ IF signal, image signal televisio

5、n receiver will have a 870M48.5M to become 38MHZ of intermediate frequency image signal. In mobile communication, a frequency and the two frequency etc In the transmitter, in order to improve the stability of transmitting frequency, uses the multistagetype transmitter. With a low frequency of the qu

6、artz crystal oscillator as the main oscillator, generating the main oscillation signal of a frequency is verystable, and then through the frequency plus or minus, multiply, divide intoradio frequency, we must use a mixer circuit, such as converting TV transposer transceiver channel, the uplink, downlink frequency in satellitecommunication transform, must be in the mixer. Thus, mixing circuit is the key module of Applied Electronic Technology and professional radio must master. Key