2015年电大作业语音滤波器复习.docVIP

目录 1 设计任务··································1 1.1设计题目······························1 1.2 设计内容及要求························1 2 滤波器的概述······························1 2.1滤波器的功能和类型·····················1 3 滤波器参数································1 3.1滤波器的传递函数·······················2 3.2滤波器的频率特性·······················2 4 滤波器的设计方案··························3 4.1设计思路·······························3 4.2单元电路的设计·························3 4.2.1滤波器的系统框图····················6 4.2.2低通滤波器的设计····················7 4.2.3高通滤波器的设计····················8 5 总电路与仿真效果··························8 5.1总电路·································8 5.2仿真效果································9 6设计心德与总结······························10 7参考文献··································10 8附录······································11 附录1：元器件清单 附录2：小组各成员所做工作说明（设计者排序），每个成员对最终方案的贡献（哪个地方是谁设计的fH=3400Hz,fL=300Hz,Av=0.1~10,阻带衰减频率=-40db/10倍频程。 第二章 滤波器的概述 功能：是指减少或消除谐波对电力系统影响的电气部件。是一种用来消除干扰杂讯的，将输入或输出经过过滤而得到纯净的直流电。对特定频率的频点或该频点以外的频率进行有效滤除的，就是滤波器，其功能就是得到一个特定频率或消除一个特定频率 Av 0.707Av (a) (b) Av 0.707v (c) 图2滤波器的幅频特性曲线 滤波器的设计方案 4.1设计思路 考虑到实用性，带负载能力要比较强，要满足输入阻抗要足够高，输出阻抗要足够小；要满足阻带衰减频率等于或大于40db/10倍频程，由于在理论上，一级二阶滤波电路的衰减频率为40db/10倍频程，在实际做板子时，衰减频率没有达到40db/10倍频程，所以要考虑到讲几个滤波电路级联在一起，提高衰减频率。 我们知道，带通滤波电路可以有一个高通和一个低通的滤波电路级联而成，再级联上一个带通的滤波电路，提高衰减频率。电路的增益Av=10，在设计电路时计算好阻值和容值。 上图依次是低通、高通、带通幅频图 4.2单元电路的设计 4.2.1滤波器的系统框图 语音滤波器的设计原理：一个一级低阶低通滤波器与一个一级高通滤波器的级联，然后带通就可以形成语言滤波器的功能。 4.2.2低通滤波器的设计 f(H) 10~100 100~1k 1k~10k 10k~100k C(uf) 10~0.1 0.1~0.01 0.01~0.001 0.001~0.0001 表4.2.1滤波器工作频率与电容取值的对应表 压控电压源电路 电路形式 电路参数 Av=1+R4/R3 电路元件值 Av 1 2 4 6 8 10 R1 1.422 1.126 0.824 0.167 0.521 0.462 R2 5.399 2.250 1.537 2.051 2.429 2.742 R3 开路 6.752