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Concepts for the generation and the measurement of highly linear frequency ramps are presented. The fractional ramp synthesiser concept shown here is able to generate frequency ramps with a very low phase noise level, a very good frequency linearity and reproducibility. </p><p style=&quot;line-height: 20px;&quot;> Related to the bandwidth of the generated frequency ramps of 4.5 GHz a relative linearity error below 4&#x00B7;10^–10 is demonstrated in a prototype system. This linearity error is close to the limit set by the phase noise floor of the ramp generators and marks a significant improvement over existing aproaches (Musch and Schiek, 2000). The basic measurement sensitivity due to the phase noise is 1.8&#x00B7;10^–10 without averaging. </p><p style=&quot;line-height: 20px;&quot;> As the phase noise is important for the linearity of the frequency ramp the set-up has to be optimised for a good phase noise behaviour, too. In order to achieve this good phase noise a special phase-frequency detector is introduced that is especially designed for the use in a fractional phase locked loop.