A system, a wireless telecommunication device, a method and a computer program are provided. The system comprises: a frequency generator for supplying a frequency reference for the wireless telecommunication device, the frequency generator further being configured to generate a first frequency and a second frequency simultaneously, the first frequency having a first response to the temperature of the frequency generator and the second frequency having a second response to the temperature of the frequency generator, the second response being different from the first response; a temperature parameter generator, connected to the frequency generator, configured to generate a temperature parameter proportional to the temperature of the frequency generator by using the first frequency and the second frequency; and a frequency controller configured to adjust the frequency reference on the basis of the temperature parameter.