This video will compare the electromagnetic interference; EMI generated by the clock signals from internally and externally clocked sigma-delta modulators. Isolated sigma-delta modulators have been proven to provide very high accuracy and robust current and voltage sensing in noisy industrial motor application environments. There are two types of isolated sigma-delta modulators. One with an internal clock signal and the other that receives the clock signal from an external source. The sigma-delta modulators generate an output digital bit-stream data corresponds to the input analog signal. The output digital data has to be synchronized as much as possible the clock signal. The output data will then be sampled at the microcontroller at the same clock signal frequency for further filtering and decimation.
For the first part of the video, we will show if the same microcontroller, an FPGA in this case, can correctly receive the output data from both types of sigma-delta modulators. For the second part of the video, we will compare the electromagnetic interference or in short, EMI, generated by the clock signal of both sigma-delta modulators.