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标题: 术语解释“zero crossing counter” [打印本页]
作者: xiongbindhu    时间: 2013-6-24 17:17
标题: 术语解释“zero crossing counter”
术语解释“zero crossing counter”,干啥用的？
作者: skatecom    时间: 2013-6-24 19:29
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作者: zgq800712    时间: 2013-6-24 22:58
骚年，google会用不？. D* P! f$ s  L  W5 K
作者: 风吹摇摆    时间: 2013-6-25 08:37
zgq800712 发表于 2013-6-24 22:58
( u  U8 q# X3 w+ j( q* p8 x# ]+ `+ E骚年，google会用不？

& U9 W$ [) j$ I# Q: j不要用古狗，用百度！% v$ t) m3 A* ~
作者: 木头脑瓜    时间: 2013-6-25 08:57
风吹摇摆 发表于 2013-6-25 08:37
7 ]4 R* t9 E0 ^# A8 @: {不要用古狗，用百度！
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狗主的地盘敢不用古狗^_^
作者: 超級狗    时间: 2013-6-25 09:07
本帖最后由 超級狗 于 2013-6-25 15:24 编辑
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; I1 b1 M+ S% B用途很廣，我找到的並非全部，大家參考一下好了。
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零交越計數器（Zero Crossing Counter）" y' V+ B+ p, m- e( V# U$ ~2 R
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解釋︰/ ^( O" F' A3 e& i
以零做為基準點的計數器，當訊號跨越零點時才計數。3 v! Z: `5 v% E9 ?  e9 S

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9 _2 U* ^' w: H- ]' A1 S! ~( n應用︰
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......
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我以前的工作經驗，交換機（PBX）有用到。振鈴產生器（Ring Generator）會在零交越（Zero Crossing）時才將振鈴繼電器（Ring Relay）切換回正常的位置，避免電話端殘存的高電平回灌交換機（PBX），將振鈴產生器（Ring Generator）打死！
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{:soso_e163:}
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作者: xiongbindhu    时间: 2013-6-25 12:37
超級狗 发表于 2013-6-25 09:07
2 w) k. ]# W& H* O1 ~用途很廣，我找到的並非全部，大家參考一下好了。& r3 S# g: y4 G. \

. X" W! `6 j* ?* u1 v; h& K零交越計數器（Zero Crossing Counter）

1 Y; A* [( O5 b5 C{:soso_e163:} & X4 N# h* S8 S
我看的资料这边，那应该是用来测量信号频率的。
9 K1 w( u9 M1 s; y* I" X2 V3q，gogo
作者: zgq800712    时间: 2013-6-25 15:00
Zero Crossing Counter" ]5 k! B6 S( A, c

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7 E* X; p& s' u  P8 HIn some DSP applications, it can be very helpful to know how many times your signal has crossed the zero-line (amplitude origin). * R$ E! n& u8 `1 v+ k$ v

5 F% G8 V% r. W$ SHow is this helpful?  Well, zero-crossings can tell you very quickly if your signal is composed of high frequency content or not.  Let's say your sample rate is 50kHz and over a small window of 1,000 samples there are 500 zero-crossings.  That would mean that every two samples crosses the zero-line (i.e. 12.5kHz)
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In speech processing, the zero-crossing counts can help distinguish between voiced and un-voiced speech.  Un-voiced sounds are very noise-like ('Shh' and 'Sss' for example).  In addition, zero-crossings could also be used to determine if your signal has a DC offset.  If you signal is 'muted' and you are not seeing alot of zero-crossings might mean that your signal is offset from the zero-line0 t) c1 \) Z1 y  R, ~
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One nice thing about the matlab code below is that it is implemented in a very DSP-friendly way.  It ports very easily into C-Code and does minimizes the amount of conditional statements for faster processing time.



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