Hi all.
I've a general question regarding the output of a filter. I've a circuit that outputs an AC voltage which I need to apply a long pass filter to and then read into an ADC.
The ADC reads values from 0-5V, but the signal swings both positive and negative. What is the best way to filter this signal so I only get positive voltages?
I've looked at a few active filters (eg Sallen-Key) and considered just running the -Vcc rail of the op-amp to ground, which clips the output to positive. However, in the modelling I've done this appears to change the overall response of the filter and the output becomes attenuated. Ideally I'd like to be a unity gain response. This is also a portable device so I need to be as economic as possible with power draw.
Any suggestions would be hugely appreciated. Thanks in advance.
Stuart
I've a general question regarding the output of a filter. I've a circuit that outputs an AC voltage which I need to apply a long pass filter to and then read into an ADC.
The ADC reads values from 0-5V, but the signal swings both positive and negative. What is the best way to filter this signal so I only get positive voltages?
I've looked at a few active filters (eg Sallen-Key) and considered just running the -Vcc rail of the op-amp to ground, which clips the output to positive. However, in the modelling I've done this appears to change the overall response of the filter and the output becomes attenuated. Ideally I'd like to be a unity gain response. This is also a portable device so I need to be as economic as possible with power draw.
Any suggestions would be hugely appreciated. Thanks in advance.
Stuart