METHOD FOR REDUCING TIME OF SCANNING BROADCASTING CHANNEL AT DIGITAL SET-TOP BOX

摘要

PURPOSE: A method for reducing time of scanning broadcasting channels at a digital set-top box is provided to skip automatic search to broadcasting channels which are unable to be synchronized, based on a noise value of each broadcasting channel. CONSTITUTION: A method for reducing time of scanning broadcasting channels at a digital set-top box includes the steps of setting a symbol rate and a sub-range respectively(S31); resetting frequency of a derotator and entering frequency for phase control(S32); checking a first AGC(Automatic Gain Control)(S33); reading a noise indicate related to the corresponding broadcasting channel recorded at an FEC IC(Forward Error Correction IC), and skipping the current broadcasting channel procedure if the noise indicate is more than a reference value(S34); executing timing check and carrier wave search if the noise indicate is lower than the reference value(S35); entering new frequency for phase control before resetting the frequency of the derotator if the FEC IC is not locked(S36); terminating if tuner centering is completed and range is terminated(S37); changing the next sub-range and terminating a loop(S38-S39).