Abstract:

The main factors resulting in local frequency tracking error are analyzed based on the principles of the tracking local oscillator for frequency agile radars of rotary tuning magnetron type. There are two kinds of errors, cold tracking error and post-hot-tracking error. The former determines the frequency range which should be revised by the hot tracking circuit, while the later is the final frequency error of the local oscillator. Stress is laid on considering the cold tracking error.The relationship between the tracking error and the different circuit parameters is analyzed according to the error expression of closed loop system in combination with all key elements of typical cold tracking circuit. Also, the other factors contributing to the tracking error are described. Meanwhile a short description of the post-hot-tracking error items is presented. The above analyses are useful in taking measures to improve the tracking accuracy of a local oscillator system in frequency agile radars.