Vector-signal-generator with two σδ-PLL´s

This paper presents a new architecture in vector signal generators, composed of two σ-δ phase lock loop synthesizers. The use of σ-δ PLL gives the advantage of high phase noise performance and the accurate phase points required for complex modulation schemes. At the same time, it avoids the use of digital-to-analog converters, mixtures and extra filters. This concept is different from classic PLL phase modulators, which cannot be used to form VSG. Measurement results are also included, showing the phase modulation obtained by the new σδ-VSG.