kingkong83
New Member
Hello.. i have 1 problem that relative with the low filter (Before i have post 1 topic about the ECG system) and i want to change the circuit for the low pass filter... before i am using the 150Hz for the low pass filter and now i want change it to the 60Hz.. But after i changed the value of R1 (to 2.65kohm) and R2 (to 26.5kohm) i cannot get the ECG signal
Before chaged the value, the signal very small after i pass through the notch filter, why??) i am using the formula : 1/2*pi*f*c to change the value for LPF.. Any mistake in the calculation??
Em.. i also want to change the previous circuit (low pass filter part) to butterworth filter using sallen key circuit for improve my circuit performance.. But i dunno how to what value should i put.. Can u help me put the value?? i want set the frequency at 60 Hz and 120 Hz..
The last question is the connect to replace the LPF part is correct?? i have upload the circuit below..
Before chaged the value, the signal very small after i pass through the notch filter, why??) i am using the formula : 1/2*pi*f*c to change the value for LPF.. Any mistake in the calculation??
Em.. i also want to change the previous circuit (low pass filter part) to butterworth filter using sallen key circuit for improve my circuit performance.. But i dunno how to what value should i put.. Can u help me put the value?? i want set the frequency at 60 Hz and 120 Hz..
The last question is the connect to replace the LPF part is correct?? i have upload the circuit below..