Phase Projection Method For Instantaneous Measured Frequency

IFM is developing since 70s of last century prompted by EW. And more and more IFM methods are introduced. The classic method for IFM is delay line and phase detection. It's main idea is split a signal into two pathways, and these two signals are delayed by different time, as we known, for a sine wave the difference time delay means that they have different phase, and we also know that the phase of a sine wave is related with it's frequency, so if we can get the phase difference between these two pathways, a equation can be constructed to calculate the frequency of the sine wave.Although delay line and phase detection is a important method for IFM, it's measure precision is not satisfaction. So, many people pay their attention on the algorithms, since this way can get more high measure precision, as the computer and semiconductor device development. It is true that algorithms can get high measure precision, but it cost more time, because the digital device such as DSP and FPGA need time to calculate the result.As mentioned before, the delay line and phase detection method covers the main idea for IFM. Almost all the IFM method according to a process: frequency transformed to phase information, and then to amplitude information. Frequency is transformed into phase by delay line, and phase information is transformed into amplitude by the phase detector.This paper introduced some co-state IFM methods and algorithms. And pay more attention on the IFM algorithms, analyzed the phase calculate method and some simulation results gained, realized an IFM module and get credible result.Chapter 1 and chapter 2 of this paper introduced the main method and algorithms for IFM, in chapter 3, discussed how to realize this IFM module. In chapter 4 you can get some simulation results for phase calculate algorithms. Practical design is discussed in chapter 5 and chapter 6.