Frequency Transmitter Controller Synchronized With GPS Based On Android

With the rapid development of modern communication technology,electronic countermeasure and electronic system,the requirement of the transmitting performance of the frequency is higher and higher.This paper comes from the project which is jointly developed by our laboratory and a military research institute.The project requires us to develop a low power frequency transmitter controller synchronized with GPS that can provide high precision frequency signal for pulse power supply and communicate with it.The frequency transmitter controller can realize high accuracy frequency signal transmission and switch automatically and quickly according to the frequency table.The output frequency value is mainly the frequency points of some special requirements.Based on the analysis of the function and performance of the frequency transmitter controller,this paper aims to find a solution of generating frequency which can ensure high accuracy frequency and switch the frequency points according to the frequency table fast and automatically,and which can also use mobile phone or other Android equipments to perform real-time control.Using GPS disciplined oscillator as the system standard frequency source.The standard 10MHz frequency by PLL frequency synthesizer chip will be converted into 24903680Hz.The frequency as the reference frequency of pulse counting method,which can meet the requirements of all the frequency error.Referring to the circuit design,based on the programmability of FPGA which is integrated into the Nios II processor chip as CPU to construct the system on a programmable chip,the controller attributing added allocation and coordination of IP core can achieve the performance requirements.The use of serial port and Android USB interface for communication,the development and design of mobile phone application software,the completion of human-computer interaction function,which can realize the frequency table editing,downloading and uploading,and real-time monitoring of launch parameters.With the PLL frequency synthesizing reference frequency,the pulse counting method is used to generate the target frequency,so that the frequency point can be switched quickly and accurately.After testing,the accuracy of the reference frequency can reach10^-7,and the synchronization error of GPS reached 0.2?s.When the launch frequency is less than 100 Hz,the resolution is 0.1Hz,the error is less than 0.1Hz,and when the launch frequency is greater than or equal to 100Hz,the resolution is 1Hz,the maximum error is less than 2.5Hz,which can meet the requirements of the system accuracy.The host computer using Android mobile phone or tablet computer,makes the human-computer interaction more intelligent and convenient.The frequency of large-scale data storing,editing,importing and exporting is to be possible,.Combined with the using of SOPC,the system is more integrated and programmable.