Abstract
The amplitude-to-time conversion (ATT) technique is proposed as a detection method which can achieve a wide dynamic range and a high Signal to Noise ratio. Laser absorption measurement is known for its high sensitivity for a gas concentration. To enhance the sensitivity for detection, it is required that the minute attenuation in a direct signal is amplified. In order to verify the principle and evaluate the performance, a unique system is developed by the authors. As a result of the test, measurement of an amplitude attenuation of about 1/2,000,000 was successfully achieved. The system is compared to a 14-bit A/D converter, which has proved that its sensitivity is almost two hundred times the 14bit A/D converter.
