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<?xml-stylesheet type="text/xsl" href="https://community.arm.com/utility/feedstylesheets/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/"><channel><title>ecg conditioning</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/29960/ecg-conditioning</link><description> 
hi 

 
I&amp;#39;m thinking about designing a portable ecg unit, but i&amp;#39;m affraid
about 2 or 3 dummie&amp;#39;s things (after reading i&amp;#39;m still confused
btw)0: 

 
1: Two lead or 3lead testprobe?? 
2: If i can use 2 leads for test purposes, wher i must place it in my</description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: ecg conditioning</title><link>https://community.arm.com/thread/61632?ContentTypeID=1</link><pubDate>Tue, 05 Feb 2013 07:38:31 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:25949560-ef0a-4afc-a2fc-44dacbb7d3ee</guid><dc:creator>Chinzei Tsuneo</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;&amp;gt; 1: Two lead or 3lead testprobe??&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
Three leads are essential, two differential inputs, and an
indifferent electrode (base potential) to cancel the potential
difference between body and the ECG amplifier. When your ECG device
is &amp;quot;floating&amp;quot;, ie. battery-driven stand alone (or wireless), you may
apply two leads.&lt;/p&gt;

&lt;p&gt;
&lt;i&gt;&amp;gt; i only recover a 60 hz amplified and homogeneous signal at
the output of the ad8237&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
Power line noise is much greater than ECG voltage (around 1mV at
body surface).&lt;br /&gt;
Your ECG device should have filter to suppress power line noise.&lt;/p&gt;

&lt;p&gt;
&lt;i&gt;&amp;gt; i followed the schema of the datasheet btw, except that i
put 3.3V !!&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
This schema?&lt;br /&gt;
&lt;a href="http://www.analog.com/static/imported-files/data_sheets/AD8237.pdf"&gt;www.analog.com/.../AD8237.pdf&lt;/a&gt;&lt;br /&gt;

Figure 77. AD8327 in ECG&lt;/p&gt;

&lt;p&gt;
How did you implement &amp;quot;patent protection&amp;quot; black box on the
schema?&lt;br /&gt;
There comes a filter network, bandpass from around 0.67 to 40 Hz on
standard ECG equipment.&lt;/p&gt;

&lt;p&gt;
You may add digital filter after the amplifier, like these
articles.&lt;/p&gt;

&lt;p&gt;
Heart-Rate and EKG Monitor Using the MS430FG439 - TI&lt;br /&gt;
&lt;a href="http://www.ti.com/lit/an/slaa280a/slaa280a.pdf"&gt;www.ti.com/.../slaa280a.pdf&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;
ECG Front-End Design is Simplified with MicroConverter - Analog
Devices&lt;br /&gt;

&lt;a href="http://www.analog.com/library/analogDialogue/archives/37-11/ecg.html"&gt;www.analog.com/.../ecg.html&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;
&lt;br /&gt;
&lt;/p&gt;

&lt;p&gt;
I&amp;#39;ve copied my post on TI MSP430 forum, here. It&amp;#39;ll also give you
some suggestions.&lt;/p&gt;

&lt;p&gt;
ECG:MSP430FG439&lt;br /&gt;

&lt;a href="http://e2e.ti.com/support/microcontrollers/msp43016-bit_ultra-low_power_mcus/f/166/t/100464.aspx"&gt;e2e.ti.com/.../100464.aspx&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;
The boards on the ECG appnotes are designed to pick up
differential voltage from fingers on both hands. Usually, the axis of
heart inclines from the center line of body. This inclination makes
the differential voltage at both hands, caused by the heart
electrical activity (ie. ECG). Some people, however, has
straightly-positioned heart. Thin and tall shape often has this heart
position. In this case, the differential voltage at both hands are
reduced. Attach a wire to one of the electrode, and pick up the
voltage of foot and hand.&lt;/p&gt;

&lt;p&gt;
Another consideration is contamination of electrical activity of
muscles (EMG: electromyogram). EMG generates much higher voltage
(around 100mV) than ECG (around 1mV). To relax the arm muscles, the
testee sits in front of a desk, and places both elbows on the desk.
And (s)he touches to the electrodes on the desk softly.&lt;/p&gt;

&lt;p&gt;
Tsuneo&lt;/p&gt;
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