Producing low-noise test signals for a fast infrared optical sensor for measuring transmission or absorption of light from a thermal light source through a gas, film or liquid comprises using a lock-in amplifier

摘要

Producing low-noise test signals for a fast infrared optical sensor for measuring the transmission or absorption of light from a thermal light source through a gas, film or liquid comprises sending the high-frequency component of the detector signal from a pyroelectric detector to a lock-in amplifier equipped with a low-pass filter and adding the total detector signal to the output signal of the lock-in amplifier. Producing low-noise test signals for a fast infrared optical sensor for measuring the transmission or absorption of light emitted from a thermal light source through a gas, film or liquid, where the temperature and thus output power of the light source is modulated by the current flowing through it so that a detector signal with a signal shift is produced at the output of the sensor, comprises sending the high-frequency component of the detector signal from a pyroelectric detector to a lock-in amplifier equipped with a low-pass filter and adding the total detector signal to the output signal of the lock-in amplifier.