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 includes a flowcell and an adjustable circuit model of the flowcell, which are differentially coupled through output amplifier circuits and galvanically isolated from sources of signal degradation. The output of the difference amplifier is coupled to a DC/RF discriminator and associated downstream processing circuitry. Respective amplitude and phase outputs of the DC/RF discriminator are used to control amplitude and phase adjustment circuits of the adjustable circuit model, so as to automatically track amplitude and phase variations in the non-linear behavior of the flowcell, to mirror the characteristic impedance of the flowcell, thereby making the bridge insensitive to variations in the flowcell.