Based On New Digital Phase-shifted Clock Frequency Measurement `method

The novel uniform precision frequency measure method this paper mentioned is valuable in instantaneous frequency measure field. It is newly-type method which aim at the radar IF measure. It can use less hardware resource to complete the high accuracy frequency measurement, so it reduces the research cost greatly.Firstly, this paper analyses the origin of measure error, and introduces some methods that can improve the measure accuracy or decreases errors. Then this paper introduces a common method which called high accuracy-cursor interpolating method particularly and explains the limitations of this method. Secondly, the paper provides two ways to break the limitations of this method immediately, the technique of clocks lock and the means of clocks count, and selects the means of clock as the final design scheme.The high frequency and high accuracy clock used in this paper is provided by Phase Lock Loop (PLL). The PLL multiplies the clock, which OCXO (Oven voltage Controlled Crystal Oscillator) output, and trail the clock phase, constituting a clock frequency control system; consequently the clock can be regarded as the standard counter clock.This design is based on the technique of time interpolating and the technique of clock multiplying by PLL, it have no use for extra clock benchmark, with the characteristic of high accuracy, high stability and simple structure. The all parameters of this design satisfy the requirements of measure system.