Description: In surveillance radars of the «old» park in the systems AFT frequency discriminators are used, which are designed on a lamp element base. They are characterized by instability of parameters, and, accordingly, mistakes in determining the frequency detuning. It is proposed to design frequency discriminators on digital devices, in particular, using the frequency-code converter. The analysis of the errors in the digital frequency discriminator is carried out.
Keywords: radar station, automatic frequency trim, frequency discriminator, frequency-code converter