Data converter for imaging data acquisition system.

摘要

Improved data converter circuitry for a CT data acquisition system is disclosed which makes use of a programmable gain amplifier whose gain is set according to the magnitude of a detector input signal by selecting one of several resistor voltage-divider paths at the input of a fixed gain amplifier. An auto-zero loop uses an integrating op-amp to provide periodic correction to offset voltage of the fixed gain amplifier. In a modified embodiment, an auto-zero loop is provided for correction of both the fixed gain amplifier and a serially-connected A/D converter.