SIGNAL TRANSMITTER WITH CONTINUOUS PHASE MODULATION BASED ON DIGITAL SIGNAL PROCESSING AND MEMORY ELEMENTS.

摘要

The invention describes a method and apparatus for generating single-h and multi-h CPM signal waveforms, in which all the signal-generation parameters can be reconfigured. This apparatus amply beats the transmitters disclosed in the prior art, such as that based on memories and that based on integration, in terms of hardware resource consumption, while also having reliable performance in terms of SQNR for any of the implementations. The described generation methodology is divided into two steps: one associated with the moving average term and one with the autoregressive term. The present invention proposes a generation of the autoregressive term based on digital signal processing and memory elements. The proposed method for generating CPM signals is carried out by DSP and memory elements in order to improve the cases in which the transmitter based only on DSP has poor performance in terms of SQNR. When the symbols to be transmitted are multiplied by the one or more modulating indices, the product is sent to an interpolation filter, which responds to the pulse with the PSR of the CPM scheme. On the other hand, in the autoregressive section, the symbols to be transmitted are multiplied by the numerator of the one or more modulation indices in order to generate a change in the current position of the phase. The sum of the outputs of the autoregressive term obtained from memory elements and the autoregressive term generated by the interpolation filter is used as an argument for the normalised sine and cosine functions.