关于带通型信号抽样定理，请教老师~

dingdangt

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;">试求某<span lang="EN-US">312kHz</span>～<span lang="EN-US">552 kHz</span>带通型信号的抽样频率<span lang="EN-US">fs</span>。<span lang="EN-US"><p></p></span></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><b style="mso-bidi-font-weight: normal;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt;">第一种做法：</span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><b style="mso-bidi-font-weight: normal;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt;">因为<span lang="EN-US"> B</span>＝<span lang="EN-US">fH</span>－<span lang="EN-US">fL</span>＝<span lang="EN-US">552</span>－<span lang="EN-US">312</span>＝<span lang="EN-US">240</span></span></b><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"><br/>&nbsp;&nbsp;&nbsp;<b style="mso-bidi-font-weight: normal;">kHz</b></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"></span><b style="mso-bidi-font-weight: normal;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt;">可得<span lang="EN-US"> n</span>＝<span lang="EN-US">fL/B</span>＝<span lang="EN-US">312/240</span>＝<span lang="EN-US">1.3</span></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><b style="mso-bidi-font-weight: normal;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt;"><span lang="EN-US"></span></span></b><b style="mso-bidi-font-weight: normal;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt;">取整数<span lang="EN-US"> n</span>＝<span lang="EN-US">1</span></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><b style="mso-bidi-font-weight: normal;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt;"><span lang="EN-US"></span></span></b><b style="mso-bidi-font-weight: normal;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt;">所以<span lang="EN-US"><span style="mso-spacerun: yes;">&nbsp; </span>fs=2(fL</span>＋<span lang="EN-US">fH) /</span>（<span lang="EN-US">2n</span>＋<span lang="EN-US">1</span>）＝<span lang="EN-US">576</span></span></b><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;">kHz</span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;">第二种做法：</p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt;"><strong>因为<span lang="EN-US"> B</span>＝<span lang="EN-US">fH</span>－<span lang="EN-US">fL</span>＝<span lang="EN-US">552</span>－<span lang="EN-US">312</span>＝<span lang="EN-US">240</span></strong></span><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"><strong>kHz</strong></span></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><span><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"></span></span><span><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"><strong>n取小于FH/B的最大整数，FH/B=2.3，取n=2</strong></span></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><span><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"></span></span><span><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"><strong>所以fs=2B+2（FH-nB)/n=552<span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;">kHz</span></strong></span></span></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><span><p><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"><strong><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"></span></strong></span></p></span></p><p><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"><strong><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"></span></strong></span></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 27pt;"><span><p><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"><strong><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;">哪种对？谁能该我讲讲？谢谢</span></strong></span></p></span></p><p><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;"><strong><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 'Courier New'; mso-bidi-font-size: 10.5pt;">哪种对？谁能该我讲讲？谢谢</span></strong></span></p><p></p>

[此贴子已经被作者于2008-4-20 20:27:57编辑过]