Abstract: A synchronizing unit generates synchronized pulse sequences from an external digital signal pulse sequence, with the assistance of an internal work clock, using two serially connected flip-flops for accepting external digital signal pulse sequences and for providing synchronized data and clock pulses corresponding thereto. The clock of the external digital signal pulse sequence has the same clock frequency as the work clock with which the data is to be synchronized, but with an undefined phase relation. For the purpose of synchronizing, during a acquisition state, a switching stage is driven into a first state by the clock of the external digital signal pulse sequence, and a divider is triggered by the output of the switching stage. In a second state of the switching stage, corresponding to a normal operating state, the first switching stage is deactivated and the divider operates continuously.

Abstract: In rotating mass memories, for example magnetic disk memories, write or, respectively, read operations are controlled by a static status signal. A plurality of read heads having assigned preamplifiers is selectively activatable with the assistance of a selection signal and is through connectible to a common signal shaping device for further amplification and filtering of the read output signal. The signal shaping device has an input stage assigned thereto in which the differential outputs of the preamplifiers are respectively connected in parallel to the signal shaping device via a respective coupling capacitor. The input stage also comprises first analog switches arranged between an operating voltage and the coupling capacitors and comprises second analog switches in series in the signal lines.