s06-02.htm

关于扩频的一些好资料

            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">为跳频图案、跳频频率以及跳频起止时刻完全一致的同步情况。图中黑色矩形块代表接收端的跳频图案，带有斜线的矩形块代表发送端的跳频图案，即所要接收的外来信号的跳频图案。图</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">(b)</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">和图</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">(c)</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中，接收端跳频图案的瞬时频率比外来信号高出一个中频。</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt"><SPAN 
            style="mso-spacerun: yes">&nbsp;</SPAN></SPAN></P>
            <P class=MsoNormal 
            style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%">　</P>
            <P class=MsoNormal 
            style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%"><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt"><O:P></O:P></SPAN></P>
            <P class=MsoNormal 
            style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; LINE-HEIGHT: 150%"><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt; COLOR: navy">6.2.4 </SPAN><SPAN 
            style="FONT-SIZE: 12pt; COLOR: navy; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">跳频信号的波形</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt; COLOR: navy"><O:P> 
            </O:P></SPAN></P>
            <P class=MsoNormal 
            style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%"><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">与定频连续信号波形不同，跳频信号的波形是不连续的，这是因为跳频器产生的跳变载波信号之间是不连续的。频率合成器从接受跳频指令开始到完成频</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt; mso-spacerun: yes">&nbsp; 
            </SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">率的跳变需要一定的切换时间。为了保证其输出的频率纯正而稳定，防止杂散辐射，在频率切换的瞬间是抑止发射机末级工作的。</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt"><O:P> </O:P></SPAN></P>
            <P class=MsoNormal 
            style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%"><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">频率合成器从接受指令开始建立振荡到达稳定状态的时间叫作建立时间；稳定状态持续的时间叫驻留时间；从稳定状态到达振荡消失的时间叫消退时间。从</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt; mso-spacerun: yes">&nbsp; 
            </SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">建立到消退的整个时间叫作一个跳周期，记作</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">Th</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。建立时间加上消退时间叫作换频时间。只有在驻留时间</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">(</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">记作</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">T<SUB>D</SUB>)</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">内才能有效地传送信息。图</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">6</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">－</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">10</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">给出频率</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt; mso-spacerun: yes">&nbsp; 
            </SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">合成器的换频过程和载波信号的波形。</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt"><O:P> </O:P></SPAN></P>
            <P class=MsoNormal 
            style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%" 
            align=center><SPAN lang=EN-US style="FONT-SIZE: 12pt">&nbsp;<IMG 
            height=279 src="s06-02.files/s6-10.gif" width=500 border=0><O:P> 
            </O:P></SPAN></P>
            <P class=MsoNormal 
            style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%" 
            align=center><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">图</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">6</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">－</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">10<O:P> </O:P></SPAN></P>
            <P class=MsoNormal 
            style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%" 
            align=center><SPAN lang=EN-US 
            style="FONT-SIZE: 12pt"><O:P></O:P></SPAN></P>
            <P class=MsoNormal 
            style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; LINE-HEIGHT: 150%"><SPAN 
            lang=EN-US 
            style="FONT-SIZE: 12pt; mso-spacerun: yes">&nbsp;&nbsp;&nbsp; 
            </SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">跳频通信系统为了能更有效地传送信息，要求频率切换占用的时间越短越好。通常，换频时间约为跳周期</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">Th</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">1/8 ~ 1/10</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。比如跳频速率每秒</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">500</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">跳的系</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">统，跳周期</SPAN><SPAN 
            lang=EN-US 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">Th</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">＝</SPAN><SPAN 
            lang=EN-US 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">2ms</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，其换频时间为</SPAN><SPAN 
            lang=EN-US 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">0.2ms</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">左右。跳频速率每秒</SPAN><SPAN 
            lang=EN-US 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">20</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">跳的系统，跳周期是</SPAN><SPAN 
            lang=EN-US 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">50ms</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，其换频时间约为</SPAN><SPAN 
            lang=EN-US 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">5ms</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">。</SPAN></P></TD>
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