Figure 4.
The free-space optoelectronic encoder based on ROMA. (a) Comparison between traditional photoelectric encoders and ROMA-based photoelectric encoders. (b) The working schematic diagram of the reconfigurable free-space optoelectronic encoder. (c) Optical and electrical modulation characteristics of ROMA; the upper part is the photocurrent value under eight light intensities (from 1.4 to 132 μW cm−2, 100 ms) encoded from ‘000’ to ‘111’, and the lower part is the corresponding current value after programming with voltage pulses (100 ms) with different amplitudes. (d) Decoding accuracy curve using three different output current data. (e) The comparison diagram of NMSE and SNR for encoding by solely using Iread1, which denotes the sum of the output current under the original photoconductivity, encoding by exclusively employing Iread2, which indicates the sum of the output current under the photoconductivity after electrical pulse modulation, and encoding through the combination of Iread1 and Iread2. (f) The distribution map of Iread1 and Iread2 in the 2D space, which contains 4096 groups of data (representing from 000000000000 to 111111111111), and each group encompasses 91 datapoints.