Research On Signal Phase Detecting Method Based On Amplitude Measurement

Signal phase measurement has always been one of the key points in the field of radio frequency and microwave communication systems.For example,in the design and test of mobile communication,antenna,microwave devices,electromagnetic compatibility radiation emission and so on,the measurement of signal phase is indispensable.With the development of integrated circuits,the problem of electromagnetic compatibility has become increasingly serious.To solve the problem of EMC,it is necessary to locate the EMI source accurately,determine the coupling path of the EMI wave,and then adopt corresponding technical means to reduce the EMI interference to the equipment.On the one hand,in order to establish the most accurate equivalent interference source model,it is necessary not only to scan the electromagnetic field amplitude completely through the near-field measurement system,but also to obtain the phase information of the electromagnetic field;on the other hand,even if the location of the interference source is located,the coupling circuit of the interference signal is needed.The path is still uncertain,but if the phase difference between the sensitive device and the jammer can be measured and the frequency information of the jammer can be combined,the propagation distance between the jammer and the jammed device can be inferred,thus the coupling path of the jammer signal can be inferred.The phase measurement of high frequency electromagnetic radiation signal is always a technical problem.The special phase testing system has huge equipment,high price and strict technical specifications when used.Therefore,how to use the existing test equipment and choose the right measurement method to achieve accurate,effective and simple measurement of the phase of EMI signal is a subject worthy of further study and discussion.In this paper,a method of measuring signal phase by spectrum analyzer is presented,which is called amplitude phase measurement.The amplitude information of signal can be obtained by spectrum analyzer,and the signal phase can be deduced by amplitude.This method can not only measure the signal phase of multi-port devices,but also extract the signal phase of single-port or non-port PCB board.This method can be applied to near-field scanning measurement system.The phase information can be calculated based on the amplitude information of magnetic field and electric field,which makes up for the shortcomings of the existing methods of measuring signal phase in this field.This paper first introduces the principle of amplitude phase measurement method,which is based on the deduction of power synthesizer working in ideal state.Considering the actual situation of power synthesizer,on the basis of the ideal amplitude phase measurement method,the isolation factor is taken into account,and the theory is optimized to reduce the calculation error of the theory.Then,according to the basic principle of amplitude phase measurement method,a set of signal phase measurement system is designed.The theory of amplitude phase measurement is verified by simulation and experiment.The simulation results show that under the ideal condition of the power synthesizer,the phase calculated by the amplitude phase measurement method is in good agreement with the simulation results,and the maximum error is only 0.09 degrees.By using the actual power synthesizer simulation,the phase calculated by the optimized theoretical method is closer to the simulation results than that by the ideal amplitude phase measurement method,which greatly reduces the calculation errors caused by the unsatisfactory power synthesizer.Poor.In the experimental part,the phase of microstrip circuit and NGD circuit is measured.The experimental results show that the phase calculated by the amplitude phase measurement method is basically the same as that measured by the vector network analyzer,and the maximum error is 5 degrees.Finally,a broadband active power divider and power synthesizer with low transmission loss,small reflection and high isolation are designed.The principle of the design is introduced in detail and realized in the simulation.The main device in this design is transistor amplifier,which is GVA-81+ power amplifier produced by Mini Circuit Company.The simulation results show that the broadband active power divider works at 200 MHz-6 GHz,the echo loss of each port is less than-20 dB,the isolation of the output branch is less than-34 dB,and the output power of a single branch can reach 11 dBm at 0.6 GHz.In the range of 200MHz-6GHz,the echo loss of each port of the active power synthesizer is less than-21 dB in the working frequency band,the isolation of the two input terminals is less than-30 dB,and the output power of the power synthesizer can reach 12 dBm at 0.5GHz.