| 摘要 |
<p>A mobile telephone has a high frequency system clock (41) and a processor (61) arranged to process polling signals received while the telephone is in its standby condition. When polling signals are not being received, it is possible for the telephone to be placed in a sleep condition, by de-activating the system clock. Re-activation occurs in response to a calibrated number of clock cycles produced by a lower frequency sleep clock (65). Upon re-activation, system clock counters (43,44), specifying sub-frame periods and frame periods are re-loaded so that they may be re-activated at the required phase. The phase of these counters is compared with signals received from base stations and modifications are made to system counts as required. The extent to which modifications are required is also used to re-calibrate the sleep clock. <IMAGE></p> |
