Design of a High Echo Density Reverberation System

MasterThe computation complexity of the reverberation system increases with the number of digital filters. A typical high echo density reverberation system is composed of a large number of all-pass filters. Therefore, the entire structure of the reverberation system is very complex and operates slowly. To speed operation of the system, a new digital filter must be added so that the system is composed of a small number of all-pass filters. In this thesis, we propose a high echo density reverberation system. The system consists of three components: a diffusion part, a delay part, and a reverberation part. This system is based on a new digital filter, called ‘two all-pass filters in all-pass filter’. This filter simplifies the overall structure of the reverberation system and gives it a high echo density. So it reduces memory requirements of the system. In simulations, the proposed reverberation system operates faster compared than the Yamaha reverberation system. The proposed reverberation system also has higher echo density than the Yamaha reverberation system.일반적으로 잔향기 (reverberation system)의 계산 복잡도 (computation complexity)는 잔향기에 사용되는 디지털 필터의 수에 따라 함께 증가한다. 높은 잔향 밀도 (echo density)를 가지는 잔향기는 많은 수의 전역통과 필터 (all-pass filter)로 구성된다. 따라서 잔향기의 전체 구조는 매우 복잡하고, 연산량이 많기 때문에 연산 시간이 길다. 잔향기의 연산 시간을 줄이기 위해서는 새로운 디지털 필터를 사용하여 잔향기에 사용되는 전역통과 필터의 수를 줄이는 것이 필요하다. 본 논문에서는 높은 잔향 밀도를 가지는 새로운 잔향기를 제안한다. 제안하는 잔향기는 세 부분으로 이루어져 있으며, 새로운 디지털 필터인 two all-pass filters in all-pass filter (2APFinAPF)를 사용하였다. 이 새로운 디지털 필터를 사용함으로써 기존 잔향기에 비해 전역통과 필터를 적게 사용 할 수 있어서 잔향기의 전체 구조가 간단해졌고, 새로운 디지털 필터의 특성 및 잔향기의 구조로 인해 잔향 밀도를 높일 수 있었다. 제안하는 잔향기의 성능을 분석하기 위해 실제 상용되고 있는 Yamaha社 잔향기를 구현하여 제안하는 잔향기와 성능을 비교 분석하였다. 전산 실험 결과 제안하는 잔향기는 Yamaha社 잔향기와 비교하였을 때 연산 시간이 16.7% 감소하였고, 잔향 밀도는 10.2% 증가하였다

Effects of aluminum of titanium substitution on the structures and properties of lithium ferrites

Maste

다중 표적 상황에서 계산 복잡도 및 탐지 성능을 개선한 CFAR 탐지기 연구

학위논문(박사) - 한국과학기술원 : 전기및전자공학부, 2024.2,[v, 98 p. :]In radar systems, target detection is required for situational awareness, and constant false alarm rate (CFAR) detectors are mainly used to detect targets. In recent radar systems, multiple target situations such as swarm drones, vehicle radars, ground target detection/tracking radars, sea target detection/tracking radars, and aerial target detection/tracking radars occur frequently, and accordingly, the importance of target detection performance in multiple target situations is increasing. Since the detection performance degrades when using conventional CFAR detectors in multiple target situations, many studies are being conducted to improve the detection performance in multiple target situations. In addition, it is necessary to reduce the computational complexity to implement CFAR detectors with improved detection performance in multiple target situations in real-time radar systems. In this dissertation, CFAR detectors that reduce the computational complexity and improve the detection performance in multiple target situations were studied, and in particular, CFAR detectors with a new structure were proposed using the average value of the selected samples and the ordered statistics of sub-reference cells to improve the detection performance in multiple target situations. The first method, which uses the average value of selected samples, requires no prior information, has low computational complexity, and shows high detection performance in multiple target situations. This dissertation presents the concept and the structure of the method, compares detection performance in multiple target situations using computer simulations, and presents detection performance comparison results using flight test data. The second method is a method using the ordered statistics of sub-reference cells, which does not require prior information, has low computational complexity, and shows high detection performance in multiple target situations. This dissertation presents the concept and the structure of the method, compares detection performance in multiple target situations using computer simulations, and presents detection performance comparison results using flight test data. Comparing and verifying the proposed CFAR detectors and the conventional CFAR detectors using the computer simulations and the flight test data, the proposed CFAR detectors have low computational complexity, do not require prior information, and have improved detection performance in multiple target situations. Based on the results presented in this dissertation, the proposed CFAR detectors are expected to apply to real-time processing radar systems and exhibit high detection performance in multiple target situations.한국과학기술원 :전기및전자공학부