DC/RF BLOOD CELL DETECTOR USING ISOLATED BRIDGE CIRCUIT HAVING AUTOMATIC AMPLITUDE AND PHASE BALANCE COMPONENTS

摘要

A differential DC/RF bridge-configured flowcell particle detector contains both the flowcell proper, and an adjustable circuit model of the flowcell, which are differentially coupled through output anplifier circuits and galvanically isolated from sources of signal degradation that would impair the ability of the bridge to conduct accurate particle detection measurements. The output of the difference amplifier is coupled to a DC/RF discriminator and associated downstream processing circuitry. By virtue of its linear optical isolation and self-powered configuration, the modified Wheatstone bridge detector of the invention is effectively a "floating" bridge, that galvanically isolates the front-end signal detection circuits. The adjustable circuit model automatically tracks amplitude and phase variations in the non-linear behavior of the flowcell, thereby making the bridge insensitive to variations in the flowcell.