IEEE TRANSACTIONS ON BROADCASTING, VOL. 54, NO. 2, JUNE 2008
249
Modulation and Pre-Equalization Method to
Minimize Time Delay in Equalization Digital
On-Channel Repeater
Heung Mook Kim, Sung Ik Park, Jae Hyun Seo, Homin Eum, Yong-Tae Lee, Soo In Lee, and Hyuckjae Lee
Abstract—This paper presents novel modulation and pre-equal-
ization methods to minimize a signal processing time delay in
the Equalization Digital On-Channel Repeater (EDOCR) for the
ATSC terrestrial digital TV system. The proposed modulation
method uses Equi-Ripple (ER) filter for Vestigial Side Bands
(VSB) pulse shaping instead of conventional Square Root Raised
Cosine (SRRC) filter. And the proposed pre-equalization method
calculates pre-equalizer filter coefficients by comparing a base-
band signal as a reference signal and a demodulated repeater
output signal, and then creates new VSB pulse shaping filter coef-
ficients by the convolution of the ER filter and the pre-equalizer
filter coefficients. The new VSB pulse shaping filter minimizes the
time delay of EDOCR by adjusting the number of its pre-taps and
also compensates the linear distortions due to the use of the ER
filter and mask filter.
Index Terms—ATSC, modulation,
on-channel
repeater,
pre-equalization, SFN.
I. INTRODUCTION
TERRESTRIAL television broadcasters in general operate
transmitters and translators according to the geographical
locations of their coverage areas. In both analog and digital tele-
vision broadcasting, Multiple Frequency Networks (MFNs) that
assign different channels to each transmitter and translator have
been used to cover service areas. However, the use of MFNs
is very inefficient in the aspect of using frequencies since it is
unable to share channels among a number of transmitters and
translators unless the distance between two coverage areas is
far enough.
Therefore, Single Frequency Networks (SFNs) that operate
multiple transmitters and repeaters on the same frequency is de-
sirable for the efficient use of frequencies. Especially, in the re-
cent transition