抑制载波双边带解调电路设计

论文编号:TX343  论文字数:10065,页数:30

摘要
 
 在通信系统中，基带信号所占的有效频带往往具有频率较低的频谱分量，如在信道中直接传输，就会严重影响信号传输的有效性和可靠性。因此不适宜直接进行传输的。在通信系统的发射端通常需要调制过程，将信号的频谱搬移到所希望的位置上，使之转化成适合信道传输的调制信号。而在接收端则需要解调过程，以恢复原来有用的信号。调制解调过程常常决定了一个通信系统的性能。随着数字化波形测量技术和计算机技术的发展，可以使用数字化方法实现调制与解调的过程。同时调制还可以提高性能，特别是抗干扰能力，以及更好的利用频带。
 本设计主要是通过一个乘法器，将一个同频同相的载波信号与抑制载波的双边带调幅信号相乘，来实现频谱搬移。将已调信号的频谱搬回到原点位置，就可以得到原始的调制信号频谱，从而恢复出原始信号。这种解调方式具有抗噪声抗干扰能力强、功率有效性高等特点。

关键词：调制，解调，基带信号，调制信号

ABSTRACT

 In the communications system, the proportion of base-band signal is often an effective band of the spectrum with low frequency components, such as direct transmission channel, it will seriously affect the effectiveness of signal transmission and reliability. Therefore not suitable for direct transmission. In communication systems usually require the transmitter modulation process, the removal of the signal spectrum to the desired position, so that suitable channel into the modulation signal transmission. The receiving end in the demodulation process is required in order to restore the original useful signal. Modulation and demodulation process often determines the performance of a communication system. With the digital waveform measurement technology and the development of computer technology, you can use the method of digital modulation and demodulation process. At the same time, modulation can also improve performance, especially the anti-interference ability, as well as better use of bandwidth.
 This design mostly multiplied a carrier signal and a signal of sidebands of suppressed by multiplication sign to carry the spectral. To resume the barbarism signal by carrying the spectral of the modulated signal.For this mode of demodulation,having a good ability of demur Noise and Molest,a good validity power and so on.

Key words: Modulation, Demodulation, Base-band signal, Modulation signal
 
目录

摘要 I
ABSTRACT II
第1章 引言 1
 1.1 背景 1
 1.2 研究内容 1
第2章 抑制载波双边带的解调 3
 2.1 解调的概述 3
 2.1.1 解调的定义 3
 2.1.2 解调的任务及目的 3
 2.2 解调的分类 3
 2.2.1 相干解调 4
 2.2.2 包络检波 4
 2.3 锁相环的应用 4
 2.3.1 锁相环的定义 4
 2.3.2 锁相环的基本组成 4
 2.3.3 锁相环的基本原理 5
 2.3.4 锁相环的用途及分类 5
 2.3.5 锁相环在调频和解调电路中的应用 6
 2.4 抑制载波双边带解调电路的原理 7
 2.4.1 抑制载波双边带调幅（DSB-SC） 7
 2.4.2 抑制载波双边带解调 8
第3章 抑制载波双边带解调电路的设计 10
 3.1 MC1496的概述 10
 3.2 MC1496的内部结构及原理 10
 3.3 中频解调电路模块 11
 3.3.1 解调电路模块各组成单元 12
 3.3.2 解调电路各模块功能 12
 3.3.3 解调电路的测试点 16
 3.4 解调电路的其它芯片 16
 3.4.1 芯片LM358 16
 3.4.2 芯片HD74LS04P 17
 3.4.3 芯片DM74LS74AN 17
第4章 中频解调电路模块PCB板的制作 18
 4.1 Protel99SE概述 18
 4.2 原理图的设计 18
 4.2.1 原理图的设计流程 19
 4.2.2 焊接与调试 19
 4.3 调试图形展示 20
 4.4 调试后总结 23
第5章 结束语 24
致谢 25
参考文献 26