Editing Pulse Necklace 15Nov2009

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==Op-Amp Experiment==
==Op-Amp Experiment==


Chung-Hay bought a couple AD 620 op-amp chips to experiment with bypassing the Open ECG chip at filtering/amplifying the bio-electric signal. We worked off of the lab document [http://www-univie-ac-at_cga_courses_BE513_Instrumentation_pe3quc01.pdf BE 513 Lab], in addition to the AD 620 data sheet. The sample circuit for detecting ECG in the AD 620 data sheet included two other op-amp components. We have yet to figure out what the op-amp circuit attached to the gain-control resistor does... Chung-Hay is going to seek EE assistance on that front.
Chung-Hay bought a couple AD 620 op-amp chips to experiment with bypassing the Open ECG chip at filtering/amplifying the bio-electric signal. We worked off of the lab document [www-univie-ac-at_cga_courses_BE513_Instrumentation_pe3quc01.pdf BE 513 Lab], in addition to the AD 620 data sheet. The sample circuit for detecting ECG in the AD 620 data sheet included two other op-amp components. We have yet to figure out what the op-amp circuit attached to the gain-control resistor does... Chung-Hay is going to seek EE assistance on that front.


To look at the output signal from AD 620, we resorted to a virtual oscilloscope - link and code are in the next section. Unfortunately, we saw only noise from the oscilloscope. We tried switching the gain-control resistor from 98 ohms (two 47 ohm resistors) to 1 kohm. That only lowered the amplitude. We were using red dot electrodes, so the ECG signal was entering the chip reliably. More work to be done on this front.
To look at the output signal from AD 620, we resorted to a virtual oscilloscope - link and code are in the next section. Unfortunately, we saw only noise from the oscilloscope. We tried switching the gain-control resistor from 98 ohms (two 47 ohm resistors) to 1 kohm. That only lowered the amplitude. We were using red dot electrodes, so the ECG signal was entering the chip reliably. More work to be done on this front.


==Oscilloscope Code==
==Oscilloscope Code==
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