Time ramp random continuum!

Noob here. I would like to built a never ending “random time ramp”, for example to produce a sinusoïdal sirène that randomly goes up and down without any frequency jump (continumm). So I need that the ending value of the first ramp become the starting value of the second one, the ending value of the second one the starting value of the third one and so on… I feel there is several ways to approach this…could you please show me the light
Thanks a lot.

Certainly, LFDNoise1 would be my first thought. Also note that mathematical linearity in frequency doesn’t correpond to phenomenlogical linearity, same intervals cover a larger frequency range in higher registers, therefore compensate, e.g. with exprange. LFDNoise3 is a smoother possibility than LFDNoise1 (take the LFDNoise variants instead of LFNoise, see the remark at the bottom of the LFDNoiseX help files). For more differentiated behaviour see DemandEnvGen

Great! DemandEnvGen in addition with Dwhite is an excellent way to do that. Thanks a lot !