Accounting Research And The Cpld-based Microwave Frequencies

The general method of frequency measured is counting after a gate ,in which, a measured signal is set a high precision for a longer interval. However, based on a high speed frequency divider or a under-mixing frequency , modern microwave digital frequency divider divides the microwave frequencies to a lower one, measured the frequency of the signal, which named counting method frequency. Frequency accuracy mainly depends on the length and accuracy of the gate.The subject comes from the Qianfeng Electronics Factory in Chengdu forwards the Integrated Test System radar frequency function, which is delivered. The system consists of hardware and software. Firstly, high-speed divider is adopted, then according to a certain percentage, the input frequency is divided. Subsequently, adopted a large-scale [CPLD] and high-performance programmable logic devicemicrocontroller , data operations, handling , functional control and results are ongoing . In actual measurement, since the application of appropriate technology, automatically transform the gate time , so that equal accuracy is measured in the entire scope. Adopting 150MHZ bell used in the frequency, accuracy sets up 10-9. To get the higher measurement precision, this article points out a phase technology to further improve the accuracy of measurement . This method is not reported at both home and abroad.Count frequency is using time instead of accuracy. But in military electronic surveillance systems and electronic countermeasures, short-time signal frequency is measured, which named the instantaneous frequency measurement technology. There is a theoretical discussion in this article , another graduate completed the hardware. Finally, the article presents the measurement results of the system, as well as a certain error analysis, the results show that the system has reached the design standard.