Modulation apparatus for reducing time delay of on-channel repeater in terrestrial digital TV broadcasting system

摘要

Provided is a modulation apparatus that can reduce time delay of on-channel repeaters in a terrestrial digital television broadcasting system. The time delay is caused by a filter during the modulation operation in the on-channel repeaters. The modulation apparatus of the present research includes: a baseband signal forming unit for forming a baseband signal by combining the output signals of an equalization unit with the pre-defined field/segment synchronization signals in the on-channel repeaters; a pilot inserting unit for inserting a pilot signal to the baseband signal; an up-sampling unit for up-sampling the baseband signal with the pilot signal; a VSB filtering unit for filtering the up-sampled baseband signal based on a Window technique and/or an Equi-Ripple filter to thereby form an in-phase (I) signal and a quadrature (Q) signal; an up-converting unit for up-converting the frequencies of the filtered I and Q signals to frequencies of an intermediate frequency (IF) band; an adding unit for adding the up-converted I and Q signals and converting a resultant signal into a digital VSB signal of the IF band; and a digital-to-analogue converting unit for converting the digital signal of the IF band to an analogue signal.