Abstract: A method and apparatus for powering an electronic circuit use comparators of supply voltages and voltage regulators to facilitate powering the electronic circuit utilizing more than one supply voltage. In one embodiment, power supplies of step-up power units are controlled using comparators of step-down power units and the step-up power units temporarily provide power to accidentally disabled of step-down power units.

Abstract: A hierarchical network management system is described which includes concentrators (2A to 5A) on the individual levels (E1 to E3) of the hierarchy as well as adjustable interfaces in the concentrators for point-to-point and bus connections. An interface is provided for a bus connection on a master side. The interface takes delays into consideration. A transmission channel can be connected to the interface. The channel includes a forward bus and return line (a5, b5). Parallel addressable apparatus (8A, 8B, 8C) can be connected to the forward and return lines. A controllable change-over switch (A8, B8, C8), inserted in the return line (b5) of the transmission channel, is provided for each addressable apparatus (8A, 8B, 8C) of the parallel combination.

Abstract: The invention relates to a phase-locked loop comprising a phase detector (PD), an analog-to-digital converter (ADC), a loop filter (LF), a digital-to-analog converter (DAC) and a voltage-controlled oscillator (VCO). The phase jitter that occurs in such a hybrid phase-locked loop is reduced without enhancing the requirements as to the resolution of the digital-to-analog converter (DAC), in that a fractionizer (FR) is inserted after the loop filter (LF) that is operating at a first clock (TL), which fractionizer produces a main value (HW) and a residual value (RW), and the sum (SW) of the main value (HW) and a correction bit (KB) derived from the residual value (RW) is applied to the digital-to-analog converter (DAC) that is operating at a second clock (TA).

Abstract: In a single- or multiple-part protective cover for traction drives (for instance, chain, belt, toothed belt drives or the like), in particular for vehicle engines, vehicle drives, machines or the like, a protection of the traction drive from impairment by excessive heating during operation and from the entry of dirt particles, rainwater, snow and other foreign bodies is attained in that at least one coolant overpressure inlet opening (2) is embodied in the walls of the protective cover (1) and communicates with at least one source emitting the pre-filtered coolant at overpressure.