Frequency identification by complex spectrum

The fundamental frequency of signal is one of the important information. We can obtain the frequency of periodic wave from the peak of spectrum calculated by FFT. But the resolution of peak frequency is not so high. To get higher resolution, some methods have been proposed. They require a great deal of calculation. To improve the calculation speed, this paper proposes a new method to estimate the fundamental frequency in short observation interval using the complex spectrum. The phase component of complex spectrum gives us a useful information to increase the resolution. Using the characteristics of complex spectrum, we obtained the peak frequency with negligible error. This method requires a little caliclation. The frequency of signal can be estimated in real time when an array processor is used.