•Ratio circuits are analog circuits which produce an
output proportional to the
ratio of the 2 input signals.
•They are usually made from modules called analog multipliers.
•Examples are calculation of surface density or antigenic
receptor sites by
dividing the number of bound
molecules by the cell surface area.
•E.g. Could use
2/3 power of volume to obtain surface area - but few cytometers make this parameter so can use the square of
the cell diameter of scatter
instead to approximate.
•pH can also be measured using ratio circuits
•Calcium
ratio (using Indo-1) is also used
(discussed in later lecture)