I am developing a signal conitioning circuit for ECG.In the digital side the built in ADC of PIC18f4550 has a voltage range of 0 to 5volts. But my signal amplitude varies from -2.5 to + 2.5. Should I use a level shifter circuit? and if so can anyone provide me with the circuit and the other details...

Thanks in advance...

 

Use an opamp in the summing configuration to add your input signal to a fixed DC voltage of 2.5 Volts. The opamp should have supplies that exceed that range [-2.5..5.0], like plus and minus 6 volts or plus and minus 12 volts.

 

Thanks a lot for your reply.. will have to try it out now....