Design of A 2-18GHz Digital Frequency Discriminator using Least-squares and Candidate-selection Methods

?????? ?????? (phase unwrapping)??? ????????????(least-squares) ???????????? ????????? ?????? ????????? ????????? ????????? (Digital Frequency Discriminator: DFD) ????????? ????????????, ??? ??????????????? ????????? ?????? ????????? 4??? ????????? ????????? DFD ????????? ????????????. ???????????????, ????????? ?????? ????????? ?????? 2-6GHz?????? 2-18GHz??? 4??? ???????????? ?????? ????????? ?????? ???????????? ????????? ?????? DFD ?????? ????????? ?????? ????????????, ?????? ?????? ????????? ?????? ???????????? ???????????????, ??? ??????????????? ????????? 2-18GHz ?????? ????????? ????????? ?????? ?????? ???????????? ????????? ?????? ??????????????? ????????????. ??????, ???????????? ????????? ?????? ??????????????? ?????? ????????? ?????? ?????? ????????? ???????????? ?????? ????????? ???????????? ?????????, ??? ??????????????? ????????? ??? ?????? ?????? ????????? ?????? ????????????, ????????? ?????? ?????? ???????????? ???????????? ????????? ????????? ????????? ?????? ????????? ????????????. ????????? ????????? ?????? ??????????????? ???????????? ????????? ???????????? ???????????? ??????????????????, ??????????????? ?????? DFD??? ????????? ????????? ?????? ???????????? ?????? ??? ??????. ?????????, ????????? DFD??? ?????? ????????? ?????? ????????? ?????? ????????????, ?????????????????? ?????? ????????? ????????? ????????? ?????? ????????? ????????????.Based on the conventional 2-6GHz digital frequency discriminator (DFD) using the phase unwrapping and least-squares techniques, we propose a new 2-18GHz DFD. To compensate for lowered-precision frequency estimation due to the expanded bandwidth, the proposed DFD design employs more delay lines, accordingly accompanying high complexity. Thus, a new computationally efficient frequency estimation algorithm is also presented to overcome such high computational burden. More specifically, the proposed frequency estimation algorithm is basically based on the conventional phase unwrapping technique, along with a new candidates selection for the unwrapped phases under the condition that the phase margin is known. As a result, the computational burden required for the least-squares technique can be reduced. Finally, simulation results are provided to demonstrate the effectiveness of the proposed approach, compared with those of the conventional DFD's