Coherent demodulation of the two-level APSK signals with the symbol amplitude estimation

The study focuses on the algorithms for the coherent demodulation of the two-level amplitude phase-shift keyed signals with an estimate of the received symbol amplitude carried out by its relative comparison with the preceding symbol amplitude. Determining calibrated values of the symbol amplitudes in order to compare them with the preset threshold values is considered unnecessary in this case. Phase demodulation is implemented based on the phase detector of the multi-level phase-shift keyed signals. Symbol amplitudes are determined by the quadrature channels responses. Both analog and digital demodulation algorithms are considered. Simulation of the demodulation algorithm is carried out.

Simulation Modeling of the Accuracy of Solid-State Wave Gyroscope Characterization with Tuning of Computational Algorithms to Signal Periodicity

The setting of computational algorithms for four methods of identification of wave characteristics in the free run-out mode of standing waves in the resonator of the integrative solid wave gyroscope on observations of signals of its measuring device at time intervals that are multiples of resonator oscillation is described. In the first roughest method, measurement results are processed without taking into account the influence of the quadrature wave. It is convenient for forming initial approximations in the tasks of clarifying optimization of identification functionality in other methods. In the second method, the refined processing of measurement results is carried out taking into account the phase shift of the signals of the measuring device. In the third method, in order to provide better physical visibility and to process the results of measurements, a virtual transition to mobile axes of standing waves is introduced. In the fourth method, measurement results are processed using numerical digital demodulation procedures. Comparisons have been made for the accuracy of these identification techniques by simulation methods for theoretically set source signals. This made it possible to directly compare the original and identified characteristics of wave processes: the amplitude of the main and square standing waves, the angle of the main standing wave and its frequency. The results are presented in the absence and presence of noise in the measuring signals. The results show the specifics of the practical application of different techniques for real samples of gyroscopes. For short identification intervals, they require a special choice of interval lengths equal to the final number of resonator oscillations. With the lengthening of such intervals, this requirement for the length of the interval is weakened.