Ho-Min Eum

Equalization On-Channel Repeater for Terrestrial Digital Multimedia Broadcasting System

This paper presents technical requirements of on-channel repeaters (OCRs) to broadcast the terrestrial digital multimedia broadcasting (T-DMB) signals in single frequency network (SFN) environment. In order to meet such requirements, the configuration and implementation method of the equalization OCR are proposed. The proposed equalization OCR does not have only short processing delay, but also provides high quality transmitting signals with high power because of the rejection capability of a feedback signal introduced by incomplete antenna isolation and multipath signals existing between a main transmitter and the OCR. Computer simulations and laboratory tests results are provided to figure out performance of the proposed equalization OCR.

Modulation and Pre-Equalization Method to Minimize Time Delay in Equalization Digital On-Channel Repeater

This paper presents novel modulation and pre-equalization 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 baseband signal as a reference signal and a demodulated repeater output signal, and then creates new VSB pulse shaping filter coefficients 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.

An adaptive carrier synchronization technique for robust 8-VSB DTV reception

In this paper, an adaptive digital frequency phase locked loop (FPLL) algorithm is proposed to improve the carrier recovery performance of 8-VSB receiver. The proposed carrier synchronization technique not only provides a robust 8-VSB DTV reception in fixed and indoor environments, but also makes it possible to watch the HDTV in portable environment. This is because the proposed technique dramatically reduces tracking jitter and acquisition time and enlarges acquisition range by adopting a sign detector, pilot extract filter bank, adaptive lock detector, mode selector, and loop filter bank to the conventional FPLL algorithm.

A novel modulator for equalization digital on-channel repeater in ATSC system

In this paper we propose a novel modulator for the equalization digital on-channel repeater (EDOCR) in ATSC system. The proposed modulator uses equi-ripple VSB filter instead of conventional square root raised cosine (SRRC) filter. Since the time delay of the EDOCR modulator can seriously affect the performance of ATSC legacy receivers, it is required that the processing time should be minimized as much as possible. So, the proposed modulator focuses on reduction of time delay with minimization of its performance degradation. By simulation results, the proposed modulator has not only relative short time delay, but also little performance degradation. Also, proposed modulator using ER filter satisfies FCC RF emission mask.

Equalization digital on-channel repeater with a feedback interference canceller for the ATSC terrestrial DTV system

This paper proposes a novel equalization digital on-channel repeater (EDOCR) with a feedback interference canceller (FIC) for a single frequency network (SFN) of the advanced television systems committee (ATSC) terrestrial digital television (DTV) system. The proposed EDOCR with an FIC not only has high output power by the cancellation of feedback signals caused by insufficient antenna isolation through the FIC, but also shows better quality of output signals than conventional digital on-channel repeaters (DOCRs) by removing multipath signals existing between the main transmitter and DOCR, as well as residual feedback signals through an equalizer. Computer simulation results are provided to demonstrate the superior performance of the proposed EDOCR with an FIC.

Equalization OCR with feedback interference canceller for T-DMB system

This paper proposes a novel equalization on-channel repeater (OCR) with feedback interference canceller (FIC) to relay the terrestrial digital multimedia broadcasting (T-DMB) signals in single frequency networks (SFN). The proposed OCR does not have only high output power by cancelling feedback signals caused by insufficient antenna isolation through the FIC, but also shows better quality of output signals than the conventional OCR by removing multipath signals existing between the main transmitter and the OCR through an equalizer. In addition, computer simulations and laboratory test results are provided to figure out performance of the proposed OCR.

Design of novel distributed translator for synchronized multiple transmission networks of ATSC 8-VSB system

This paper proposes a novel digital television translator which can be used for synchronized multiple transmission networks or distributed transmission networks of ATSC system. To be used in a distributed transmission network, translators should synchronize each other in terms of frequency and data. The proposed translator, named as baseband equalization distributed translator (EDTxR), uses only the received signal from the main transmitter for synchronization. EDTxR retrieves frequency and timing information from the received main transmitter signal and use it for frequency synchronization among EDTxRs. Moreover, EDTxR adopts additional frequency synchronization scheme to compensate the frequency offset of reference clock. For data synchronization, EDTxR retrieves the symbol data from the received transmitter signal and re-transmits the same symbol data, which makes all the symbols from all EDTxRs have the same data. To assess the performance of the EDTxR, laboratory test and field test are conducted and the results show EDTxR can be used as a digital television translator with higher spectrum efficiency than legacy translator.

Distributed Translator Part 2: Laboratory Test Results

This paper presents and analyzes laboratory test results of distributed translator (DTxR) for distributed frequency network (DFN) in the ATSC (Advanced Television Systems Committee) terrestrial digital TV broadcasting system. The DTxR laboratory test is classified to receiving part test and transmitting part test. The receiving part test includes dynamic range, random noise, single echo, and adjacent channel interference. The transmitting part test includes quality of output signal (out-of channel emission, quality of transmitting signal, and phase noise), frequency synchronization among output signals, and TxID (Transmitter Identification) signals affect to the legacy receiver. By the laboratory test results, the receiving part of DTxR eliminates average -2.5 dB of single echo and has average 17.5 dB at TOV (Threshold of Visibility) under random noise environment. In addition, the transmitting part of DTxR satisfies the specification of US FCC (Federal Communications Commission), and frequency difference among DTxR output signals is less than 0.001 Hz.

Distributed Translator Part 1: Distributed Translator Technology

This paper considers technological requirements to broadcast digital television signals using distributed frequency network (DFN) in the advanced television systems committee (ATSC) transmission system and proposes distributed translator (DTxR) to meet such requirements. In the DFN, DTxR uses different frequency from main transmitter, but same among DTxRs. In addition, this paper introduces digital signal processing (DSP) techniques, which consist of demodulation, equalization, transmitter identification (TxID) generation and insertion, and modulation, to implement DTxR.

An EDOCR with a Feedback Interference Canceller for the ATSC Terrestrial DTV System

In this paper, we propose an equalization digital on-channel repeater (EDOCR) with a feedback interference canceller (FIC) for single frequency network of the ATSC terrestrial DTV system. The proposed EDOCR with FIC does not have only high output power by cancelling feedback signals caused by insufficient antenna isolation through the FIC, but also shows better quality of output signals than the conventional on-channel repeaters (OCRs) by removing multipath signals existing between the main transmitter and the OCR, and residual feedback signals through an equalizer. In addition, computer simulations are provided to figure out the superior performance of the proposed EDOCR with FIC.