Method for measuring the phase noise of a signal with the following method steps: - detecting a measurement signal with a certain measurement frequency (f 1) and with a superimposed phase noise (f 1 (t)), - dividing the measurement signal into a first measurement signal (V 1 ') and a second measurement signal (V 2 ') in each case with the certain measurement frequency (f 1) and with the superimposed phase noise (f 1 (t)), - deriving a first signal (V 1) from the first measurement signal (V 1 ') with a first frequency ((f 1 +f 1 (t))/N) which is reduced in relation to the measurement frequency (f 1) and the superimposed phase noise (f 1 (t)) by frequency reduction, - deriving a second signal (V 2) from the second measurement signal (V 2 ') with a second frequency ((f 1 +f 1 (t))/M) which is reduced in relation to the measurement frequency (f 1) and the superimposed phase noise (f 1 (t)) by frequency reduction, - determining a third signal ( V 3) with a third frequency (f 3 (t)) which is compensated by the measurement frequency (f 1) in relation to the first frequency ((f 1 +f 1 (t))/N) of the first signal (V 1), - determining a fourth signal ( V 4) with a fourth frequency (f 4 (t)) which is compensated by the measurement frequency (f 1) in relation to the second frequency ((f 1 +f 1 (t))/M) of the second signal (V 2), - determining a correlation spectrum with a frequency range from the third and fourth signal ( V 3, V 4), characterised in that the frequency reduction is effected by means of frequency division of the frequency (f 1 +f 1 (t)) of the first and second measurement signal (V 1 ', V 2 ') by a first and a second frequency divider (200, 210) respectively each of which has at least one cascaded feedback edge-controlled flip-flop circuit (240 1 to 240 n) so that the third and fourth frequency (f 1 (t)/N, (f 1 (t)/M) of the third and fourth signal ( V 3, V 4) in each case come to lie within the frequency range of the correlation spectrum and in the case of a phase difference between the phases of the first and second signal (V 1, V 2) the phases of the first and second signal (V 1, V 2) are synchronised with one another by resetting all the flip-flop circuits of the first frequency divider for frequency division of the first measurement signal (V 1 ') and of the second frequency divider for frequency division of the second measurement signal (V 2 '). - detecting a measurement signal with a certain measurement frequency (f 1) and with a superimposed phase noise (f 1 (t)), - dividing the measurement signal into a first measurement signal (V 1 ') and a second measurement signal (V 2 ') in each case with the certain measurement frequency (f 1) and with the superimposed phase noise (f 1 (t)), - deriving a first signal (V 1) from the first measurement signal (V 1 ') with a first frequency ((f 1 +f 1 (t))/N) which is reduced in relation to the measurement frequency (f 1) and the superimposed phase noise (f 1 (t)) by frequency reduction, - deriving a second signal (V 2) from the second measurement signal (V 2 ') with a second frequency ((f 1 +f 1 (t))/M) which is reduced in relation to the measurement frequency (f 1) and the superimposed phase noise (f 1 (t)) by frequency reduction, - determining a third signal ( V 3) with a third frequency (f 3 (t)) which is compensated by the measurement frequency (f 1) in relation to the first frequency ((f 1 +f 1 (t))/N) of the first signal (V 1), - determining a fourth signal ( V 4) with a fourth frequency (f 4 (t)) which is compensated by the measurement frequency (f 1) in relation to the second frequency ((f 1 +f 1 (t))/M) of the second signal (V 2), - determining a correlation spectrum with a frequency range from the third and fourth signal ( V 3, V 4),