Study on Enhancing Features of Digital Oscilloscope to Measure the Period of Weak FM Signal

This paper studied a method of applying the principle of chaos and neural network to detect FM modulation signal and calculate the period of the modulated signal. Also it advanced a way to enhance the features of digital oscilloscope (DSO) to measure the period of weak FM signal by programming and embedding it to the function database of DSO. According the characteristic of chaotic time serial, neural network selected Elman network, and constructed it while itpsilas dimensions of input and output were fixed by computing the correlation dimension of the chaotic time serial. Then, making use of the characteristic of identification of space-time of spatio-temporal neural network, it detected directly weak FM signal under chaotic background in chaotic state. Last, it obtained the variational relation of time-amplitude by calculating the frequency-time function. This way break through conventional chaotic measurement principle and is simple to embed in DSO. The experiment testified that it has a widely frequency scope and reliable result.