Enhancing digital measurement bandwidth through novel frequency folding technique

In this paper, a novel new way of increasing bandwidth for digital measuring is presented. In previous work, bandwidth is increased by increasing the sampling rate, using several samplers, or sampling more frequently. For this new approach, a custom passive LC filter structure consisting of 3 filters is designed and verified by simulation, which in a controlled manner allows for frequencies to fold over the Nyquist frequency. Results show that these filters in combination with digital signal processing realises tripling of the bandwidth for mono-frequency signals. However, for multi-frequency signals, unambiguous frequencies are not guaranteed. This is due to aliasing in the transition areas of filters of frequencies from transition bands into the initially intended pass-band of the filter