There is disclosed herein clock generation circuitry, in particular rotary travelling wave oscillator circuitry. Such circuitry comprises a pair of signal lines connected together to form a dosed loop and arranged such that they define at least one transition section where both said lines in a first portion of the pair cross from one lateral side of both said lines in a second portion of the pair to the other lateral side of both said lines in the second portion of the pair.

A non-linear transmission line device includes a magnetic element having at least one end profiled to reduce demagnetization when the element is biased. The profile may be tapered, stepped, or smoothly curved. Also disclosed is a non-linear transmission device made up of a solid magnetic element, typically of flat rectangular form.

There is disclosed herein clock generation circuitry, in particular rotary travelling wave oscillator circuitry. Such circuitry comprises a pair of signal lines connected together to form a closed loop and arranged such that they define at least one transition section where both said lines in a first portion of the pair cross from one lateral side of both said lines in a second portion of the pair to the other lateral side of both said lines in the second portion of the pair.