Object profiling using FMCW reflectometry with asymmetric method

The FMCW reflectometry is a high-resolution ranging system using an optical frequency swept laser source. The beat spectrum consists in the interference signal will analysis by FFT analysis. At the asymmetric method, the timing of the data acquisition called raising period is different with the timing of FFT analysis called the falling period. The exact percentage of both will determine quality profiling and measurement time. In our experiment, we compare the measurement time between 350 and 600 points of the number of the acquired data with the theoretical measurement time. The measurement time of theoretical theory is closer with the measurement time using 350 points of the number of the acquired data. This study proved that the clear profile is generated using the repetition frequency of the injection current modulation 1.8 kHz with the condition is the raising period (Tr = 155 μ) is shorter than the falling period (Tf = 400) at the raising mode in 22.7 sec by using 350 points of the number of the acquired data.