?? 直接式數字鎖相環頻率合成器的仿真.htm
字號:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- saved from url=(0063)http://www.mvista.com.cn/svu-www/index4/index4-4/index4-4-4.htm -->
<HTML><HEAD><TITLE>直接式數字鎖相環頻率合成器的仿真</TITLE>
<META http-equiv=Content-Type content="text/html; charset=gb2312">
<META content="MSHTML 6.00.2600.0" name=GENERATOR></HEAD>
<BODY bgColor=#e2cbc0>
<TABLE height=34 cellSpacing=2 cellPadding=2 width=755 border=0>
<TBODY>
<TR>
<TD width=187 height=2><A name=image00></A></TD>
<TD width=355 height=2><B><FONT color=#ff6633
size=+3>數字頻率合成器</FONT></B></TD>
<TD width=193 height=2><IMG height=44
src="直接式數字鎖相環頻率合成器的仿真.files/0033.gif" width=112><FONT size=+2><B><FONT
color=#00cc00><A
href="http://www.mvista.com.cn/svu-www/index4/index4-4.htm">返回</A></FONT></B></FONT></TD></TR></TBODY></TABLE>
<TABLE height=17 cellSpacing=2 cellPadding=2 width=755 border=0>
<TBODY>
<TR>
<TD width=10 height=246> </TD>
<TD width=704 height=246><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">作為實驗，如圖</SPAN><SPAN
lang=EN-US>6.5</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">所示為一個用</SPAN><SPAN
lang=EN-US>SystemView</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">實現的<A
href="http://www.mvista.com.cn/svu-www/index4/index4-4/index4-4-4.htm#image01">直接式數字鎖相環頻率的仿真電路</A>。為了節省仿真時間，參考振蕩器直接采用了較低的</SPAN><SPAN
lang=EN-US>10Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">正弦波信號（圖符</SPAN><SPAN
lang=EN-US>0</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">），而沒有采用由一個較高的參考振蕩器經過分頻</SPAN><SPAN
lang=EN-US>R</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">得到</SPAN><SPAN
lang=EN-US>f<SUB>R</SUB></SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的辦法。鎖相環的</SPAN><SPAN
lang=EN-US>VCO</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">用了一個</SPAN><SPAN
lang=EN-US>FM</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">圖符代</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">替（圖符</SPAN><SPAN
lang=EN-US>2</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">），其載波頻率設置為</SPAN><SPAN
lang=EN-US>195Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，增益為</SPAN><SPAN
lang=EN-US>20Hz/V</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。環路低通濾波器使用了一個</SPAN><SPAN
lang=EN-US>8</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">極點的貝塞爾低通濾波器（圖符</SPAN><SPAN
lang=EN-US>5</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">），帶通為</SPAN><SPAN
lang=EN-US>5Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。在濾波器前端加入了一個</SPAN><SPAN
lang=EN-US>100Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的采樣圖符以減少系統仿真時的運行時間。分頻器使用通信圖符庫中的</SPAN><SPAN
lang=EN-US>N</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">倍分頻器（圖符</SPAN><SPAN
lang=EN-US>3</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">），分頻器的</SPAN><SPAN
lang=EN-US>N/(N+1)</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">控制端未使用。若取分頻比</SPAN><SPAN
lang=EN-US>N=20</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，則鎖相環的輸出</SPAN><SPAN
lang=EN-US>f<SUB>0</SUB></SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">應該鎖定在</SPAN><SPAN
lang=EN-US>f<SUB>0</SUB> =</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">（</SPAN><SPAN
lang=EN-US>N</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">＋</SPAN><SPAN
lang=EN-US>1</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）</SPAN><SPAN
lang=EN-US>f<SUB>R</SUB> =21</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">×</SPAN><SPAN
lang=EN-US>10=210Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">上，<A
href="http://www.mvista.com.cn/svu-www/index4/index4-4/index4-4-4.htm#image02">輸出信號的頻譜圖</A>如圖</SPAN><SPAN
lang=EN-US>6.6</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">所示，在</SPAN><SPAN
lang=EN-US>210Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">出有較高的能量峰值，說明輸出的信號被鎖定在</SPAN><SPAN
lang=EN-US>210Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">上了。將</SPAN><SPAN
lang=EN-US>N</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">改設為</SPAN><SPAN
lang=EN-US>19</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，則輸出信號應該為</SPAN><SPAN
lang=EN-US>200Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，如<A
href="http://www.mvista.com.cn/svu-www/index4/index4-4/index4-4-4.htm#image03">圖</A></SPAN><A
href="http://www.mvista.com.cn/svu-www/index4/index4-4/index4-4-4.htm#image03"><SPAN
lang=EN-US>6.7</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">所示</SPAN></A><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，仿真的結果在</SPAN><SPAN
lang=EN-US>200Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">處的頻譜有峰值。改變</SPAN><SPAN
lang=EN-US>N</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">為其它值，輸出信號的頻率將變為</SPAN><SPAN
lang=EN-US>10Hz</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的整數倍。但事實上由于鎖相環的鎖定范圍限制（與濾波器帶寬和</SPAN><SPAN
lang=EN-US>VCO</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的載波最大變化范圍有關），只能輸出</SPAN><SPAN
lang=EN-US>VCO</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">載波頻率附近的幾個整數倍的頻率。</SPAN></TD>
<TD width=21 height=246> </TD></TR></TBODY></TABLE>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P><A name=image01></A></P>
<P> </P>
<P> </P>
<TABLE height=26 cellSpacing=2 cellPadding=2 width=684 border=0>
<TBODY>
<TR>
<TD width=76> </TD>
<TD width=584><IMG height=314 src="直接式數字鎖相環頻率合成器的仿真.files/image015.gif"
width=522 v:shapes="_x0000_s1108 _x0000_s1106 _x0000_s1107"><A
href="http://www.mvista.com.cn/svu-www/index4/index4-4/index4-4-4.htm#image00"><<
返回</A> </TD>
<TD width=4> </TD></TR></TBODY></TABLE>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P><A name=image02></A></P>
<P> </P>
<P> </P>
<TABLE height=25 cellSpacing=2 cellPadding=2 width=693 border=0>
<TBODY>
<TR>
<TD width=101> </TD>
<TD width=565><IMG height=304 src="直接式數字鎖相環頻率合成器的仿真.files/image017.gif"
width=378 v:shapes="_x0000_s1111 _x0000_s1109 _x0000_s1110"><A
href="http://www.mvista.com.cn/svu-www/index4/index4-4/index4-4-4.htm#image00"><<
返回</A></TD>
<TD width=7> </TD></TR></TBODY></TABLE>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P><A name=image03></A></P>
<P> </P>
<P> </P>
<TABLE height=22 cellSpacing=2 cellPadding=2 width=694 border=0>
<TBODY>
<TR>
<TD width=135> </TD>
<TD width=532><IMG height=297 src="直接式數字鎖相環頻率合成器的仿真.files/image019.gif"
width=378 v:shapes="_x0000_s1114 _x0000_s1112 _x0000_s1113"><A
href="http://www.mvista.com.cn/svu-www/index4/index4-4/index4-4-4.htm#image00"><<
返回</A></TD>
<TD width=7> </TD></TR></TBODY></TABLE>
<P> </P>
<P> </P></BODY></HTML>
?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -