<div dir="ltr"><div>Hi Booer, <br><br>If you applied flowing transformation /normalization :<br><br></div><div>y[i]= 2*(x[i] -x_mn)/ (x_max- x_min) -1 <br><br>then resultant signal y[i] will be with zero mean and range between -1 and +1. Here x_mn, x_max and x_min are mean, max and minimum of the signal. You can apply the same transformation on both AC and DC signal. <br><br></div><div>If the origin of the AC and DC signal is same and there are no frequency dependents filter in obtaining AC signal, the resultant should be identical. <br><br></div><div>Regards,<br></div><div>Manish<br></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><div><div><div>Manish Arora<br></div><div><br><span>Open Medical Devices</span> Like us on Facebook <a href="http://fb.com/openmeddev" target="_blank">fb.com/openmeddev</a><br></div><span>Phone: +91-9980836174 </span> Follow us on Twitter <a href="https://twitter.com/openmeddev" target="_blank">@openmeddev</a><br></div><a href="http://www.openmeddev.net/blog" target="_blank">www.openmeddev.net/blog</a><br><br></div></div></div></div>
<br><div class="gmail_quote">On 7 July 2015 at 18:19, bjj2909102003 <span dir="ltr"><<a href="mailto:bjj2909102003@163.com" target="_blank">bjj2909102003@163.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>
<div><span></span>Thank you, Manish.</div><div>I tried your method. But I don't ensure <span style="background-color:rgba(0,0,0,0);font-size:10.5pt;line-height:1.5">that this simple normalization in DC data is equal to AC record. Actually, I found they were not equal. And it will affect my model (based on AC record data) applying into the DC record data.</span></div>
<div>I guess AC record data is from DC record data. But I don't know what the calculation process is .</div><div><br></div><div>Regards,</div><div>Booer</div><hr style="width:210px;min-height:1px" align="left" color="#b5c4df" size="1">
<div><span>bjj2909102003</span></div>
<blockquote style="margin-top:0px;margin-bottom:0px;margin-left:0.5em"><div> </div><div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0cm 0cm 0cm"><div style="PADDING-RIGHT:8px;PADDING-LEFT:8px;FONT-SIZE:12px;FONT-FAMILY:tahoma;COLOR:#000000;BACKGROUND:#efefef;PADDING-BOTTOM:8px;PADDING-TOP:8px"><div><b>From:</b> <a href="mailto:openmeddev@gmail.com" target="_blank">Manish Arora</a></div><div><b>Date:</b> 2015-07-07 01:19</div><div><b>To:</b> <a href="mailto:bjj2909102003@163.com" target="_blank">bjj2909102003</a></div><div><b>Subject:</b> Re: [Eeglablist] EEG AC and DC record problem</div></div></div><div><div class="h5"><div><div><div dir="ltr"><div><div>Hi Booer,<br><br>I don't know if I understood your requirements completely, but you can recenter the DC mode data around zero by subtracting simply subtracting mean of the signal from each data point. <br></div><br>Regards,<br></div>Manish<br></div><div class="gmail_extra"><br clear="all"><div><div><div dir="ltr"><div><div><div>Manish Arora<br></div><div><br><span>Open Medical Devices</span> Like us on Facebook <a href="http://fb.com/openmeddev" target="_blank">fb.com/openmeddev</a><br></div><span>Phone: +91-9980836174 </span> Follow us on Twitter <a href="https://twitter.com/openmeddev" target="_blank">@openmeddev</a><br></div><a href="http://www.openmeddev.net/blog" target="_blank">www.openmeddev.net/blog</a><br><br></div></div></div></div>
<br><div class="gmail_quote">On 6 July 2015 at 19:18, bjj2909102003 <span dir="ltr"><<a href="mailto:bjj2909102003@163.com" target="_blank">bjj2909102003@163.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div>
<div><span></span><span style="color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:13px;line-height:normal">Hi, everyone.</span><div style="margin:0px;padding:0px;border:0px;vertical-align:baseline;color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:13px;line-height:normal"><font style="margin:0px;padding:0px;border:0px;vertical-align:baseline" color="#000000">Recently, I recorded my EEG data in AC mode. And I made the model based on AC mode data (<span style="margin:0px;padding:0px;border:0px;vertical-align:baseline;font-family:'Courier New';font-size:10pt">range centred around zero</span>). Now I want to analyze on-line EEG data by my previous model. But the online data is acquired in DC mode (value is big and not <span style="margin:0px;padding:0px;border:0px;vertical-align:baseline;font-family:'Courier New';font-size:13.3333px">centred around zero</span>) by access SDK. I don't know how to convert DC mode data into AC mode data so that I can apply the previous model into the data?</font></div><div style="margin:0px;padding:0px;border:0px;vertical-align:baseline;color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:13px;line-height:normal"><font style="margin:0px;padding:0px;border:0px;vertical-align:baseline" color="#000000"><br></font></div><div style="margin:0px;padding:0px;border:0px;vertical-align:baseline;color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:13px;line-height:normal"><font style="margin:0px;padding:0px;border:0px;vertical-align:baseline" color="#000000">Thank you.</font></div><div style="margin:0px;padding:0px;border:0px;vertical-align:baseline;color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:13px;line-height:normal"><font style="margin:0px;padding:0px;border:0px;vertical-align:baseline" color="#000000">Booer</font></div></div>
<div><br></div><hr style="width:210px;min-height:1px" align="left" color="#b5c4df" size="1"><span><font color="#888888">
<div><span>bjj2909102003</span></div>
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