A pulsed radar level gauge system for measuring the distance to a surface of a material contained in a tank, said system comprising: frequency generating circuitry, adapted to generate a first clock frequency and a second clock frequency; a frequency regulator configured to control a frequency separation between the first and second clock frequencies towards a frequency separation set-point; a frequency separation evaluation circuit arranged to generate a power-up signal when said frequency separation is within a predefined frequency range; a radar level gauge circuit configured to: - generate a transmit signal in the form of a pulse train with a transmit pulse repetition frequency based on said first clock frequency, - generate a reference signal in the form of a pulse train with a reference pulse repetition frequency based on said second clock frequency, - transmit said transmit signal towards said surface, - receive a return signal caused by a reflection of said transmit signal at said surface, - provide a level output based on a relationship between said return signal and said reference signal; and power management circuitry configured to: in absence of said power-up signal, not power said radar level gauge circuit to provide a level output, and in presence of said power-up signal, power said radar level gauge circuit to provide a level output. frequency generating circuitry, adapted to generate a first clock frequency and a second clock frequency; a frequency regulator configured to control a frequency separation between the first and second clock frequencies towards a frequency separation set-point; a frequency separation evaluation circuit arranged to generate a power-up signal when said frequency separation is within a predefined frequency range; a radar level gauge circuit configured to: - generate a transmit signal in the form of a pulse train with a transmit pulse repetition frequency based on said first clock frequency, - generate a reference signal in the form of a pulse train with a reference pulse repetition frequency based on said second clock frequency, - transmit said transmit signal towards said surface, - receive a return signal caused by a reflection of said transmit signal at said surface, - provide a level output based on a relationship between said return signal and said reference signal; and - generate a transmit signal in the form of a pulse train with a transmit pulse repetition frequency based on said first clock frequency, - generate a reference signal in the form of a pulse train with a reference pulse repetition frequency based on said second clock frequency, - transmit said transmit signal towards said surface, - receive a return signal caused by a reflection of said transmit signal at said surface, - provide a level output based on a relationship between said return signal and said reference signal; and power management circuitry configured to: in absence of said power-up signal, not power said radar level gauge circuit to provide a level output, and in presence of said power-up signal, power said radar level gauge circuit to provide a level output. in absence of said power-up signal, not power said radar level gauge circuit to provide a level output, and in presence of said power-up signal, power said radar level gauge circuit to provide a level output.