SPECTRUM ANALYZER AND MEASURING APPARATUS FOR MEASURING LINE WIDTH OF LIGHT SPECTRUM USING SAID SPECTRUM ANALYZER

摘要

PURPOSE:To measure in real time with an apparatus at low cost by providing an ultrasonic optical-modulator driven by a signal to be measured, a laser light source which radiates laser lights to said optical-modulator, a line sensor for detecting a diffracting light and a frequency characteristic displaying device. CONSTITUTION:This apparatus comprises the following: an adder 21 wherein an output of a photo-receptor 16 used as an input of one part, an oscillator 22 becoming an input to the other part, an amplifier 23 for amplifying the output of the adder 21, an ultrasonic optical- modulator 24 having a transducer 25 driven by the output of the amplifier 23, a laser light source 26 which radiates a light of a predetermined wavelength and intensity to the optical- modulator 24, a line sensor 28 which detects a diffracting light 29 of the modulator 24, and a line width displaying device 30 which displays the line width based on the output of the line sensor 28. A beat signal from the element 16 is multiplied and amplified with a signal from the oscillator 22, thereby driving the modulator 24 through the transducer 25 then, at this time, the light from the light source 26 is diffracted by the angle corresponding to each frequency component and input to the sensor 28. As a result, the frequency component of the electric signal from the element 16 is present on the sensor 28 and displayed on the device 30. Accordingly, an apparatus enabling real time measurement can be realized in a simple structure at low cost.