The Design Of The Economical Frequency Measurement By Broad-band Phase Coincidence Detection

This paper mainly introduces a practical frequency measurement scheme which based on phase coincidence detection theory. And depending on it, this frequency-measuring meter overcomes the±1 word count error and achieves high measurement precision on a wide frequency rage. Its principle has spread both national and abroad.In this frequency meter, the realization of phase coincidence detecting circuit and the parts of counting are programmed and designed in the EP1C3T144 chip, which is one of the series of ALTERA Corporation Cyclone; The computation and the display work are mainly completed by MCU, which is one serie of ATMEL Corporation's MCS-51. The display mode of this instrument uses the liquid crystal module controlled by MCU ; Moreover we add the function of frequency calibration, making sure the high measurement accuracy while using the high constant VCXO which even has relative higher aging rate as frequency standard can be obtained.All the test proved that this system is more accurate, integrate and stable.