术语解释“zero crossing counter”

xiongbindhu · 发表于 2013-6-24 17:17

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术语解释“zero crossing counter”,干啥用的？

skatecom · 发表于 2013-6-24 19:29

zgq800712 · 发表于 2013-6-24 22:58

骚年，google会用不？

风吹摇摆 · 发表于 2013-6-25 08:37

zgq800712 发表于 2013-6-24 22:58
/ E8 h/ { Q) g) r& O骚年，google会用不？

不要用古狗，用百度！

木头脑瓜 · 发表于 2013-6-25 08:57

风吹摇摆发表于 2013-6-25 08:37
/ w2 ?; E% r: l: D# d* G/ a不要用古狗，用百度！

狗主的地盘敢不用古狗^_^

超級狗 · 发表于 2013-6-25 09:07

本帖最后由超級狗于 2013-6-25 15:24 编辑

用途很廣，我找到的並非全部，大家參考一下好了。

零交越計數器（Zero Crossing Counter）

解釋︰
以零做為基準點的計數器，當訊號跨越零點時才計數。

優點︰

對於不斷變換的訊號有較精準的頻率量測值。
有些控制希望在零點時做變化調整，才不會有副作用。6 M/ `9 W5 C' c' J

應用︰

影像處理
語音辮識
光學分析
都普勒（Doppler）雷達
電源供應器功率因子調整（PFC）。+ X2 j6 {! ]5 |! _* w6 H9 O" m

......

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！

{:soso_e163:}

xiongbindhu · 发表于 2013-6-25 12:37

超級狗发表于 2013-6-25 09:07 & p3 g* u" |7 s }' T7 J) O
用途很廣，我找到的並非全部，大家參考一下好了。( z j6 i; h' h
( E3 O, m$ L- n* ]
零交越計數器（Zero Crossing Counter）

{:soso_e163:}
我看的资料这边，那应该是用来测量信号频率的。
3q，gogo

zgq800712 · 发表于 2013-6-25 15:00

Zero Crossing Counter

In some DSP applications, it can be very helpful to know how many times your signal has crossed the zero-line (amplitude origin).

How 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)

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-line

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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术语解释“zero crossing counter”

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