| 摘要 |
An accuracy in the data transfer rate of 0.25 % is required according to USB specifications. In order to generate a clock signal, which renders this accuracy possible, the invention enlists the use of a clock generator unit that operates without quartz. The inventive clock generator unit comprises a n internal clock generator (11), a pulse counter (17), which is connected to t he internal clock generator (11), a pulse number memory (18), and a pulse filte r (14). The pulse counter counts the number of the internally generated clock pulses between two pulses of the synchronization signal (16), which are transmitted according to the USB specification. The difference between the determined pulse number and a specified pulse number is evaluated and is use d for controlling the pulse filter (14) that suppresses pulses, thereby resulting in the generation of a stabilized clock signal (13).
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