數(shù)字示波器不能夠直接測量AM 調(diào)制信號，更不能測量微弱的AM 調(diào)制信號。本文運用混沌和Elman神經(jīng)網(wǎng)絡作為檢測模型，通過混沌時間序列中重構相空間，獲得嵌入維數(shù)，確定神經(jīng)網(wǎng)絡結構，并采用單步預測混沌時間序列的方法，實現(xiàn)混沌背景下AM 調(diào)制信號參數(shù)檢測。實驗說明，該方法逼近目標精度高，網(wǎng)絡適應能力強，從混沌背景中檢測出AM 調(diào)制信號的周期和幅度，誤差小。將上述方法運用到數(shù)字示波器設計中，可增加數(shù)字示波器測量微弱AM 信號的功能。
關鍵詞：混沌；神經(jīng)網(wǎng)絡；AM 信號；數(shù)字示波器；測量；
Abstract: Digital oscilloscope neither measures AM signal, nor weak AM signal. This paper described a method of using Elman neural network to achieve modulation signal parameters detection on chaos background. At first, reconstructed phase space on the time sequence of the chaotic background, and obtained the input dimension by lorenz equation, then confirmed network structure of the neural network, last, forecasted chaotic time series by the single-step forecasting methods. This method has properties of high approaching precision, high ability of network adaptive, high stability, not only can detect transient signal, periodic signal from the chaos background, but also can accurately detect the target signal the shape, including amplitude and period etc. These methods will be applied to the design of oscilloscopes, digital oscilloscope measurements can be realized weak signal functions.
Keywords: Chaos; Elman Networks; AM signal; Digital Oscilloscope; measure;