Slice level adjustment unit and EPG data obtaining device using the same

A slice level adjustment unit for performing adjustment of a slice level with respect to an EPG signal whose transmission is started at a predetermined time, in accordance with a waveform of the signal, wherein

• the unit includes a clock portion for measuring the current time,
• the unit performs a first adjustment of the slice level when the clock portion measures substantially the predetermined time and performs a second adjustment when the clock portion measures a readjustment standby time past the predetermined time,
• in the first adjustment,
• a third process is performed for detecting a maximum value and a minimum value of the signal during a predetermined period, and for deciding whether or not an average value of them is allowable to be the slice level,
• if it is decided that the average value is allowable to be the slice level in the third process,
• the average value is adopted as the slice level,
• if it is decided that the average value is not allowable to be the slice level in the third process,
• a first process for selecting an optimal level as the slice level from a group of first levels that are obtained by dividing a range between an upper limit level predetermined as an upper limit of the slice level and a lower limit level predetermined as a lower limit by a predetermined number, and
• a second process for selecting an optimal level as the slice level from a group of second levels that are obtained by further dividing a range between levels neighboring the selected level by the first process among the group of first levels by a predetermined number are performed so that the level selected in the second process is adopted as the slice level,
• in the second adjustment,
• a fourth process for deciding whether or not the slice level adopted in the first adjustment is allowable to be the slice level is performed,
• if it is decided that the slice level adopted in the first adjustment is allowable to be the slice level in the fourth process,
• the slice level adopted in the first adjustment is maintained as the slice level successively, and
• if it is decided that the slice level adopted in the first adjustment is not allowable to be the slice level in the fourth process,
• the first process and the second process are performed so that the level selected in the second process is adopted as the slice level.