摘要 |
The invention pertains to a control circuit (4) for a radiation source (2). The circuit comprises means (43) for generating an error signal (Perr) which is indicative for a difference between a measured average value of the output power of the radiation source (2) and a desired average value (Pset) of the output power of the radiation source. The circuit further comprises combining means (44, 45, 46) for generating a control signal (Sout) for the radiation source (2) in response to said error signal (Perr) and to an information signal (Sin) for modulating the radiation source. The combining means comprise first means (44) for modifying the information signal by a multiplicative factor gamma which is dependent on the error signal, and second means (45, 46) for modifying the information signal by an additive factor sigma which is dependent on the error signal. |