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# Discussion Groups | Matlab DSP | Zero-Crossing..

Technical discussion about Matlab and issues related to Digital Signal Processing.

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# Zero-Crossing.. - s7jid - Jan 4 14:10:00 2004

 All, Can anyone tell me how to find number of zero crossing (i.e. number of time signal changes sign) in matlab? Regards

# Re: Zero-Crossing.. - Mandar Rahurkar - Jan 5 21:17:00 2004

 use the sign command and find the number of transitions. Mandar --- s7jid <> wrote: > All, > > Can anyone tell me how to find number of zero crossing (i.e. number > > of time signal changes sign) in matlab? > > Regards ===== ------------------------------------- Its not life that weighs us down, Its how we carry it. ------------------------------------ __________________________________

# RE: Zero-Crossing.. - balaji srinivasan - Jan 6 1:42:00 2004

 Try this.             count = 0; thresh = 0;             for(i=0:signal_length){                         if(sig[i+1]>thresh && sig[i]<=thresh) count++;                         else if(sig[i+1]=thresh)count++;                         end;                         end;             }             count/=2; #8216;Count#8217; will have the numberof #8216;zero crossings#8217;. Bye Balaji Srinivasan -----Original Message----- From: s7jid[mailto:] Sent: Sunday, January 04, 20047:40 PM To: Subject: [matlab] Zero-Crossing.. All, Can anyone tell me how to find number of zerocrossing (i.e. number of time signal changes sign) in matlab? Regards _____________________________________ /groups.php3 Yahoo! Groups Sponsor ADVERTISEMENT --------------------------------- Yahoo!Groups Links · To ---------------------------------

# RE: Zero-Crossing.. - ulas bagci - Jan 6 15:17:00 2004

 one way is this function [n] = zc(x)% ZC number of zero crossings in x%    [n] = zc(x) calculates the number of zero crossings in xs=sign(x);t=filter([1 1],1,s);n=(length(s)-length(find(t)))/length(s);or another way is function zcr=zcr(x,dur)% function zcr=zcr(x,dur) : compute zero-crossing rate% x: input data% dur: duration of the input data [nf,len]=size(x);zcr=sum(0.5*abs(sign(x(:,2:len))-sign(x(:,1:len-1))))/dur;   best regards >From: "s7jid" >To: m...@yahoogroups.com >Subject: [matlab] Zero-Crossing.. >Date: Sun, 04 Jan 2004 14:10:25 -0000 >MIME-Version: 1.0 >X-Originating-IP: 195.92.168.167 >X-Sender: s...@yahoo.co.uk >Received: from n2.grp.scd.yahoo.com ([66.218.66.75]) by mc10-f6.hotmail.com with Microsoft SMTPSVC(5.0.2195.6713); Mon, 5 Jan 2004 07:41:56 -0800 >Received: from [66.218.66.156] by n2.grp.scd.yahoo.com with NNFMP; 05 Jan 2004 15:41:44 -0000 >Received: (qmail 17136 invoked from network); 5 Jan 2004 15:41:38 -0000 >Received: from unknown (66.218.66.166)  by m16.grp.scd.yahoo.com with QMQP; 5 Jan 2004 15:41:38 -0000 >Received: from unknown (HELO n24.grp.scd.yahoo.com) (66.218.66.80)  by mta5.grp.scd.yahoo.com with SMTP; 5 Jan 2004 15:41:38 -0000 >Received: from [66.218.67.180] by n24.grp.scd.yahoo.com with NNFMP; 05 Jan 2004 15:41:38 -0000 >Received: (qmail 25425 invoked from network); 4 Jan 2004 14:10:25 -0000 >Received: from unknown (66.218.66.217)  by m14.grp.scd.yahoo.com with QMQP; 4 Jan 2004 14:10:25 -0000 >Received: from unknown (HELO n7.grp.scd.yahoo.com) (66.218.66.91)  by mta2.grp.scd.yahoo.com with SMTP; 4 Jan 2004 14:10:25 -0000 >Received: from [66.218.67.178] by n7.grp.scd.yahoo.com with NNFMP; 04 Jan 2004 14:10:25 -0000 >X-Message-Info: JGTYoYF78jE8olZlBuY7iFQJ//URq6b1 >X-eGroups-Return: sentto-1287352-2657-1073317302-ulasbagci=h...@returns.groups.yahoo.com >X-eGroups-Return: s...@yahoo.co.uk >X-Apparently-To: m...@yahoogroups.com >Message-ID: >User-Agent: eGroups-EW/0.82 >X-Mailer: Yahoo Groups Message Poster >X-eGroups-Remote-IP: 66.218.66.91 >X-Yahoo-Profile: s7jid >X-eGroups-Approved-By: s_boucheryah via web; 05 Jan 2004 15:41:37 -0000 >X-eGroups-Remote-IP: 66.218.66.80 >Mailing-List: list m...@yahoogroups.com; contact m...@yahoogroups.com >Delivered-To: mailing list m...@yahoogroups.com >Precedence: bulk >List-Unsubscribe: >Return-Path: sentto-1287352-2657-1073317302-ulasbagci=h...@returns.groups.yahoo.com >X-OriginalArrivalTime: 05 Jan 2004 15:41:56.0657 (UTC) FILETIME=[73267A10:01C3D3A2] > >All, > >Can anyone tell me how to find number of zero crossing (i.e. number >of time signal changes sign) in matlab? > >Regards > > The new MSN 8: smart spam protection and 2 months FREE*

# RE: Zero-Crossing.. - Abdul Malik Khan - Jan 23 15:16:00 2004

 If you want to avoid for loop the following code is equivalent to balaji's code thresh = 0; N = length(sig); zc = (sig >= thresh) - (sig < thresh); count = sum((zc(1:N-1) - zc(2:N)) ~= 0); > Date: Mon, 5 Jan 2004 17:42:37 -0800 (PST) > From: balaji srinivasan <> > Subject: RE: Zero-Crossing.. > Try this. > >             count = 0; > > thresh = 0; > >             for(i=0:signal_length){ > >                         if(sig[i+1]>thresh && > sig[i]<=thresh) count++; > >                         else if(sig[i+1] sig[i]>=thresh)count++; > >                         end; > >                         end; > >             } > >             count/=2; > > #8216;Count#8217; will have the numberof #8216;zero > crossings#8217;. > > Bye > > Balaji Srinivasan > > > -----Original Message----- > From: s7jid[mailto:] > Sent: Sunday, January 04, 20047:40 PM > To: > Subject: [matlab] Zero-Crossing.. > > All, > > Can anyone tell me how to find number of > zerocrossing (i.e. number > of time signal changes sign) in matlab? > > Regards __________________________________