Abstract: In data transmitting systems, an apparatus for synchronizing the frame clock in units/nodes. The apparatus has a phase detector and a voltage controlled oscillator. At least one input of the phase detector is supplied with an incoming clock signal and another input is supplied with an output signal of the voltage controlled oscillator. The output signal of the voltage controlled oscillator is conducted over a divider, which is connected to a frame clock phase detector for setting its division factor. The frame clock phase detector is supplied with an input frame clock, the output of the variable divider, and at least one output of an output divider. The at least one output of the output divider divides the output signal of the controlled oscillator into the output frame clock. The frame clock phase detector is configured for the output of a pulse that temporarily raises or lowers the division factor of the divider when the phase difference between input and output clock deviates from a prescribable quantity.

Abstract: The temperature of a Peltier element is regulated by two control loops. In the ranges where only heating or only cooling are intended to be carried out, the regulation is provided via a voltage converter. In the critical operating range which covers the transition between heating and cooling, a low operating voltage is converted to a drive AC voltage with the aid of a polarity reversal switch and both heating and cooling are carried out, depending on the polarity. The temperature is then regulated by varying the duty ratio.

Abstract: The temperature of a Peltier element is regulated by two control loops. In the ranges where only heating or only cooling are intended to be carried out, the regulation is provided via a voltage converter. In the critical operating range which covers the transition between heating and cooling, a low operating voltage is converted to a drive AC voltage with the aid of a polarity reversal switch and both heating and cooling are carried out, depending on the polarity. The temperature is then regulated by varying the duty ratio.