Abstract: An optical transmitter for transmission of data signals includes a laser diode producing optical radiation and a photodiode which in response thereto produces a photocurrent the mean value of which corresponds to the mean optical power of the radiation. Based on the photocurrent a control circuit derives parameters for controlling the laser current so as to compensate for changes in the characteristic line thereof, which line is the relation between optical power and laser current. Such parameters include a modulation current setting parameter U.sub.mod and a bias current setting parameter U.sub.0. The bias current is controlled to remain at or above the dip in the characteristic line at relatively low current levels.

Abstract: A turbocharged engine system has an internal-combustion engine whose exhaust gases drive a turbine at a speed generally proportional to the exhaust-gas pressure. This turbine in turn drives a supercharger that feeds air to the engine intake at a pressure that is generally proportional to the turbine speed. A bypass valve connected across the turbine is opened above a predetermined engine speed to shunt the exhaust gases around the turbine and thereby prevent excessive supercharging of the engine. The pressure of the engine exhaust gases is, however, decreased steadily and proportionately with increasing engine speed above a predetermined second engine speed to operate the engine with an intake-manifold pressure that is slightly below that at which knocking would occur for increased horsepower output.