Carrier Frequency Measurement Of Modulated Signal Based On Carrier Synchronization

As an important electronic technical parameter in digital information technology,frequency occupies an indispensable position in all kinds of electronic measuring instruments.The high-precision measurement of the frequency of the signal source is a very important test content in the performance evaluation of the signal source.At the same time,the measurement results of other electrical parameters such as power corresponding of different frequencies are also different.Therefore,the high-precision measurement of frequency is the direction of people's continuous efforts in information processing technology.Taking the realization of high-precision measurement of carrier frequency of digital modulation signal as the research content,this paper makes a detailed theoretical analysis and algorithm Research on the carrier recovery and frequency measurement technology in the carrier frequency measurement of digital modulation signal,to achieve the goal of carrier recovery of modulation signal,makes it continuous in time domain to obtain frequency to overcomes the problem of low upper limit of gate width in various frequency measurement methods,and hopes to realize high-precision frequency measurement,Finally,the design is tested and verified in hardware.Firstly,this paper introduces the principle of carrier synchronous phase-locked loop and common methods of frequency measurement.Then,in order to measure the carrier frequency of single carrier frequency rectangular pulse modulation signal,this paper designed a new kind of digital phase locked loop structure.This design solves the problem that the gate width is limited by the signal pulse width in the traditional in pulse frequency measurement Then this paper designed the four modules of the new-type PLL,these modules include a sequential state transition phase detector based on XOR-AND gate,a double counter random wandering sequence filter,an improved ID counting numerical control oscillator and a Phase discrimination feedback interrupter.Then,the DPD(digital phase detector),DLF(digital filter),DPD(digital voltage controlled oscillator),PDI(phase detector Interrupter)and other modules in the new carrier recovery digital phase locked loop designed in this paper are respectively programmed and verified by Verilog HDL with Quartus?and Modelsim.Finally,the above logic design is programmed in FPGA,tested and verified,and the measurement phase error can reach an accuracy of 10^-6.