Circuit for shaping a communication signal and thus provided storage unit

Circuit (1250) for forming a communication signal, comprising a clock generator (1252, 1253, 1254, 1256) for generating a clock signal using a transmitted pulse signal for communication purposes, a detection step (1257, 1258) for detecting the frequency of the pulse signal, a frequency divider (1259) for dividing the frequency of the clock signal with a frequency dividing ratio corresponding to the detected frequency of the pulse signal, and a synchronization stage (1255) for synchronizing the frequency-divided clock signal with the pulse signal, characterized in that the recognition stage comprises (1257, 1258) a charge-change suppression circuit (1263, 1264, 1266), a change in a charge accumulation stage (1279) accumulative amount of charge each time the signal level of the pulse signal is switched during a predetermined time suppressed.