jbdavid
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Once upon a time I worked on a project with 128 analog measuring points, and we used a signal conditioning circuit per measuring point to convert the parameter we were measuring (temperature, voltage, current .. etc) into the voltage range of our ADC circuit. To give you an idea of how long ago this was, we used several chips to build the ADC itself.. (comparator, R2R chip, and SARDAC ) so we only had 1 input range to use.. and that did not accomodate negative voltages, so while there were a couple of voltages we could measure directly (ie no conditioning) many needed inversion and or scaling.. Today I'd look at using a GP Data Aquisition System (on chip) and only have special conditioning circuits..
But ONE idea you might consider would be to do the clipping in post processing.. accept the +/-10 input signal, convert to 2's complement out put data, and then do a simple latch that reads the input data if the sign is NOT set, and uses 0's if the sign bit IS set.. (that could even be in SOFTWARE or firmware!!)
Otherwise I'd have a separate amplification /rectification circuit before the mux - and I think I would probably use the diode unless I had to build 2 million units.. and then I don't know what I'd do, but who ever wanted to build 2 million units would be willing to pay me good $$ to figure out how to reduce the parts count.. and I would. and I'd spice it, and breadboard it 20 time, until I figured out how to get rid of the diode..
accuracy, speed, cost, development time, power - pick any three
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