Most underwater wireless communication system use sound waves. Since the frequency of sound waves is low, direct conversion can be used and a decimator is required for this process.The characteristics required for the decimator to be used in communication between an underwater basestation and an underwater sensor node were identified. Using Matlab, aCIC filter and a compensation filter were designed to produce the frequency response required for it. Based on this, we designed the hardware with Verilog HDL and checked its operation. The results of the design were compared with the existing decimator.A decimator includes the process of sampling data at regular intervals and filtering to prevent aliasing. A CIC filter-based decimators performs both functions. In addition, it is simple in structure,small in area and low in power consumption. Therefore, it is often used. However, a CIC filterbased decimator has a large passband droop and a wide transition region, making it difficult to use it alone. In particular,an underwater sound wave communication system has a low carrier frequency band, and thus has a low data rate and a narrow channel-to-channel spacing. Therefore, it is necessary to add filters to compensate for the frequency response. The existing decimator for underwater wave communication added a compensation filter to solve the passband droop problem and an LPF to solve the transition region problem. In this paper, only one filter was used to solve two frequency characteristics problems, and the number of taps of the proposed filter was reduced compared to the existing filter.The proposed decimator has improved performance in terms of size and power consumption, so it is expected to be used in IoT sensor networks as well as underwater communication.
Volume 11 | 07-Special Issue
Pages: 1749-1754