A /spl Sigma/-Delta synthesizer phase noise optimization for multi-symbol rate digital microwave radio

The effect of synthesizer noise on digital radio systems performances, using a variable symbol rate modem, is analyzed. A /spl Sigma/-Delta PLL approach is used to optimize the synthesizer phase noise. In order to establish the contribution of this parameter in such systems, a comparison of integrated phase noise for different symbol rates is given. Experimental results show the advantage of a proposed synthesizer on the integrated phase noise see through the modem.