Research On Precise Testing Methods For Group Delay Of Frequency-translating Devices

With the advancing of the technology in electronic systems, the requirementfor the relevant technical parameters is higer and higer. So do thefrequency-translating devices (FTD), which are the key parts of the system. Asthe main index to reflect the pahse linearity of the signal, group delay can alsodescribe the propagation delay for FTD. So how to improve the measurementprecison of group delay is an immediate problem to be solved.In this paper, the relevant concepts of group delay are introduced and themethods of group delay measurement for FTD are discussed. Based on theestablished model of FTD, the group delay is measured by different kinds ofdynamic methods and the characteristics of each method are summarized.As one of the dynamic methods, the double-frequency phase differencemethod is proposed in recent years. This method is the main topic in this paperbecause it has lots of advantages such as simple operation and high precision.First, the concept of multi-frequency phase difference method is put forwardbased on the double-frequency method. This multi-frequency method can notonly fulfil different precision requirements but also improve the measuringefficiency. Meanwhile, the results show that its accuracy is not lower comparedwith the double-frequency method under the same conditions. For thedouble-frequency phase difference method, the main parameters that aremeasuring aperture and measurement interval can affect the measurement. Aresearch applying the genetic algorithm (GA) to further clarifying therelationship between these two parameters and the results, which has theadvantage of parameter optimization, is presented. Then the GA is used to selectappropriate parameters under different conditions across the entire band, whichis divied into two parts according to whether the point is measured. Thecorrectness of the simulation results is verified and the optimization design of theparameters is obtained. In the end, this paper makes an exploratory research, inwhich the compressed sensing is used to improve efficiency. The performanceamong different measurement matrices and different sparse representations iscompared. The group delay can be calculated by the reconfiguration of the signalpassing through the system. It can be found that the data is reduced bycompressed sensing when the parameters are reasonable and the conditions areright.