SYNCHRONOUS DETECTION SYSTEM FOR MULTICHANNEL INFRARED SPECTROSCOPY

摘要

Disclosed is a radiation detector which includes at least one photoconductive detector (6) and a modulator (2), which modulates in an on-off manner radiation passing to the photoconductive detector (6) from a radiation source (4). A bias source (8) is connected to one terminal of the photoconductive detector (6). A first amplifier (17) is connected to the other terminal of the photoconductive detector (6), and a second amplifier (34) receives an output of the first amplifier (17). A first phase detector (36) detects the phase of modulation of the radiation source (4) by the modulator (2) and generates a reference signal relating thereto. A switch (34) in the second amplifier (24) changes, in response to the reference signal generated by the first phase detector (36), the second amplifier between an inverting state and a non-inverting state as the modulator (2) changes the phase of modulation of the radiation.