of high and low frequency components in the read signal the parameter may also relate to the timing of transitions in the read signal such as jitter the control unit 11 may comprise means for deriving more than one parameter from the read signal s r user information s i to be recorded on the record carrier 1 is input to the control unit 15 the control unit adds error correction information to the user information and encodes the resulting information to an information signal s 2 the information signal s 2 is output to a write strategy generator 16 that converts the information signal into a series of pulses fed into a driver 17 the driver 17 controls the output power of the radiation source 6 the driver 17 radiation source 6 beam splitter 9 and objective lens 10 together form a write unit the radiation pulses emitted by radiation source 6 induce marks in the form of optically detectable changes in recording layer 3 such a mark may be written by a single radiation pulse a mark may also be written by a series of radiation pulses of equal or different lengths the actual radiation power emitted by radiation source 6 may be measured by a not shown power detector arranged in an otherwise not used side lobe of the radiation beam or in radiation reflected off a component in the optical.