Unified approach to parameter measurements of single carrier digital modulations

Abstract

Fundamental step to build an intelligent instrumentation for measurements in telecommunications is the unified approach for measuring the carrier frequency, the carrier phase offset, the phase noise and the symbol timing in the case of single carrier digital modulation. The unified approach proposed in the research concerns with (i) the amplitude modulated signals, M-ary Quadrature Amplitude Modulation and M-ary Amplitude Shift Keying and (ii) the angle modulated signals, M-ary Phase Shift Keying and M-ary Frequency Shift Keying. The carrier frequency is evaluated by means of the zero-crossing sequence, both the carrier phase offset and the phase noise are evaluated by analysing the I-Q representation of the input base-band signal in comparison with the ideal standard constellation. The symbol timing is evaluated once the occurrences of the consecutive repetition of the virtual symbol are detected. Experimental tests carried out on actual digital modulated signals highlight both the approach performance and the accuracy of the implemented algorithms.