Phase Frequency Interpretation of the Coincidence Method for Frequency to Code Conversion

Abstract

Context. The problem of fast conversion of radio signal frequency for monitoring the radial velocity of a moving object. The object of the study was the process of converting frequency into a code based on the coincidence method.
 Objective. The goal of the work is to improve the coincidence method for creating a new signal-to-code frequency converter without fixing the conversion time interval.
 Method. The coincidence method for converting the signal frequency into a code has been improved. The improved frequency conversion method, unlike the existing ones, consists in counting the number of complete phase cycles of the known and unknown signals during the time of double coincidence and asynchronous mode of hardware determination of the particle. The improved method has advantages in comparison with the method of an electro-counter frequency meter when determining the radial speed of objects and does not have a methodical error, which in an electro-counter frequency meter increases as the unknown frequency approaches the reference to 100%. However, the improved coincidence method compared to other versions has a hardware scheme for tracking the moments of coincidence and determining the fraction and does not require expensive and high-speed microprocessors to calculate the conversion results.
 Results. Based on the phase-frequency interpretation and the derived conversion equation and the proposed frequency-to-code conversion scheme using the coincidence method, a functional scheme of the frequency converter was developed. This made it possible to implement a 16-bit frequency converter in code on Intel’s MAX V series CPLD.
 Conclusions. The coincidence method for converting the signal frequency into a code received further development, which, unlike the existing ones, consists in counting the number of complete phase cycles of the known and unknown signals during the time of double coincidence and the asynchronous mode of hardware determination of the fraction.
 The influence of the frequency of signals on the time of a single measurement was studied using the coincidence method, as a result of which it was found that with an increase in the difference between the reference and unknown frequency, the time of a single measurement decreases.
 The obtained research results can be used for the development of high-speed means of converting the signal frequency into a binary code: in industrial tomography, radar and radio navigation for monitoring moving objects.