Gas differential absorbing monitoring system with fibre-optical and multi-point in mine

A differential absorption type of optical fiber multipoint monitoring system on gas of coal mine is prepared as using sine wave signal for confirming frequency to modulate a super radiation lighting tube, sending its light to one end of the first circulator and entering light to its second end then using its third end to output light to the second circulator, using its second end to output light to reflecting grating and outputting reflected light to detectors by its third end for being used as signal and reference ,converting light signal to be electric signal then sending it to data collection unit through band-pass filter for obtaining concentration of gas to be tested .