reduce dc level of spo2 signal from 7v to 0v level

[goory]

Hi...can anyone please help me to reduce dc level of my spo2 signal from 7v to 0v level???

it giving me such hard time since when i tried to display my signal in NI elvis, it just show my signal on 2v volt/div but the signal just look in linear line.when i tried to reduce volt/div to 50mV, my signal goes off n not showing in NI ELVIS...vpp for my signal only about 100mV.

my guess is try to reduce the dc level by using the AD620 by connecting +in with my signal n -in with dc +5v...it does reduce dc level..but the phase of my signal is totally change and disturbed..

can anyone help me with this problem..sory for my poor english...

 

[keith1200rs]

What is spo2?

SpO2 Pulse Oximeter Oxygen Saturation
SPO2 Saturation of Peripheral Oxygen
SPO2 Spot Oxygen Saturation
SPO2 Saturation of Hemoglobin with Oxygen As Measured by Pulse Oximetry

A circuit diagram of what you have built would enable an informed comment.

Keith.