A method of distributing clock signals CLK1, CLK2, CLK3, CLKn by a clock transmitter, the method comprising: receiving, by the clock transmitter, a plurality of clock signals CLK1, CLK2, CLK3, CLKn into a corresponding plurality of processing blocks (106, 108, 110, 112), the plurality of clock signals comprising a first clock signal CLK1 and one or more second clock signals CLK2,... CLKn; determining frequency offset data between the first clock signal CLK1 and each second clock signal CLK2, CLK2, CLKn; the method characterized by modulating the first clock signal CLK1 to enable recovery of each said clock signal CLK1, CLK2, CLK3, CLKn, with its corresponding frequency, from a modulated first clock signal CLK1_PWM, wherein the modulated first clock signal CLK1_PWM carries the frequency offset data to enable recovery of each second clock signal frequency from the modulated first clock signal CLK1_PWM; transmitting the modulated first clock signal CLK1_PWM to a clock receiver; determining, at each interval of time of one or more intervals of time, first phase offset data indicative of first phase offset movement of each second clock signal CLK2,... CLKn in the interval of time, each first phase offset movement being a movement of a phase offset between the first clock signal CLK1 and the corresponding second clock signal CLK2,... CLKn; and communicating with the receiver to allow comparison between each first phase offset movement in the interval of time and a corresponding second phase offset movement in the interval of time, the second phase offset movement being a movement of a phase offset between the recovered first clock signal CLK1_rec and the corresponding recovered second clock signal CLK2_rec, CLK3_rec, CLKn_rec. receiving, by the clock transmitter, a plurality of clock signals CLK1, CLK2, CLK3, CLKn into a corresponding plurality of processing blocks (106, 108, 110, 112), the plurality of clock signals comprising a first clock signal CLK1 and one or more second clock signals CLK2,... CLKn; determining frequency offset data between the first clock signal CLK1 and each second clock signal CLK2, CLK2, CLKn; the method characterized by modulating the first clock signal CLK1 to enable recovery of each said clock signal CLK1, CLK2, CLK3, CLKn, with its corresponding frequency, from a modulated first clock signal CLK1_PWM, wherein the modulated first clock signal CLK1_PWM carries the frequency offset data to enable recovery of each second clock signal frequency from the modulated first clock signal CLK1_PWM; transmitting the modulated first clock signal CLK1_PWM to a clock receiver; determining, at each interval of time of one or more intervals of time, first phase offset data indicative of first phase offset movement of each second clock signal CLK2,... CLKn in the interval of time, each first phase offset movement being a movement of a phase offset between the first clock signal CLK1 and the corresponding second clock signal CLK2,... CLKn; and communicating with the receiver to allow comparison between each first phase offset movement in the interval of time and a corresponding second phase offset movement in the interval of time, the second phase offset movement being a movement of a phase offset between the recovered first clock signal CLK1_rec and the corresponding recovered second clock signal CLK2_rec, CLK3_rec, CLKn_rec.