GPS Disciplined Numerically Controlled Oscillator Based on Xilinx FPGA

The high precision frequency standard is important in most frequency and time measurements. Accurate frequency standards are expensive and hard to obtain. Most of the GPS receivers provide 1 pulse per second time standard which can be used to accurately discipline a crystal oscillator with a high short-term stability. The following work uses a high frequency unadjustable crystal oscillator followed by a numerically controlled oscillator in order to obtain a high stability frequency based on 1 pulse per second GPS signal.