Richard W. Citta

An ATSC DTV receiver with improved robustness to multipath and distributed transmission environments

This paper presents the design and implementation of an 8-VSB DTV receiver for indoor and distributed transmission environments. The receiver is designed to handle severe multipath distortion from indoor and Single Frequency Network (SFN) transmission conditions. The architecture of the receiver is first introduced. The adaptive equalizer structure and design are then discussed in detail. A channel-matched filter is employed as a pre-filter such that the signal energies from different echoes are combined optimally and the signal to noise ratio of the equalizer input is maximized. Feedforward and feedback equalizers are used to handle the pre-echo (pre-cursor) and post-echo (post-cursor), respectively. The feedforward filter is designed to minimize the pre-cursors or convert them into post-cursors, while the feedback equalizer is used to eliminate the post-cursors. Initial tap coefficients are computed to speed up the convergence of these two filters based on the channel estimation. Laboratory tests show that the new prototype DTV receiver has very robust performance in multipath environments. 0 dB echoes can be handled with this receiver due to the enhanced design of the equalizer. It can withstand a -10 dB single echo within a -29.5 to +38.5 microsecond range and a 0 dB echo within a 12 microsecond range.

VSB modulation used for terrestrial and cable broadcasts

A new vestigial sideband (VSB) digital transmission system has been developed for terrestrial and cable television broadcasting, and is currently being evaluated by the FCCs Advisory Committee on Advanced Television Service (ACATS) for adoption as the US standard. Initially, this new system must co-exist with the current analog NTSC television system. An important issue is the ruggedness and reliability of the RF data signal in real world environments. Receiver synchronization and signal processing play a vital role in reliable data decoding. >

Transmit Diversity Code Filter Sets (TDCFSs), an MISO Antenna Frequency Predistortion Scheme for ATSC 3.0

Transmit diversity code filter sets (TDCFSs) are a method of predistorting the common waveforms from multiple transmitters in the same frequency channel, as in a single frequency network, in order to minimize the possibility of cross-interference among the transmitted signals over the entire reception area. This processing is achieved using all-pass linear filters, allowing the resulting combination of predistortion and multipath to be properly compensated as part of the equalization process in the receiver. The filter design utilizes an iterative computational approach, which minimizes cross-correlation peak side lobe under the constraints of number of transmitters and delay spread, allowing customization for specific network configurations. This paper provides an overview of the TDCFS multiple-input single output antenna scheme adopted in ATSC 3.0, together with experimental analysis of capacity and specific worst-case conditions that illustrate the benefits of using the TDCFS approach.

The Digital Spectrum-compatible HDTV Transmission System

The authors describe the digital spectrum-compatible (DSC) HDTV (high-definition television) System, which includes a new modulation system, a new NTSC interference filter, and reduced radiated power compared to NTSC. The system is designed to operate in the existing TV bands at 100 miles minimum cochannel distance. The NTSC interference-limited service area is unchanged. A UHF example shows that the DSC-HDTV noise-limited and interference-limited service areas are equal to those of NTSC. >

Spectrum compatible high definition television

The spectrum compatible high definition television (SC-HDTV) system achieves the encoding of a 28.9 MHz source signal for transmission over a 6 MHz channel in the terrestrial TV broadcasting bands. The signal format reduces mutual interference between existing NTSC broadcasts and the high definition broadcasts, and therefore significant amounts of currently unused spectrum space can be used for simulcasting SC-HDTV. A concise description of the system is followed by a discussion of aspects of special interest to the terrestrial broadcaster. >

HDTV adaptability to multiple media

The spectrum-compatible high-definition television (SC-HDTV) system is concisely described in the context of terrestrial broadcasting. The systems application to the other three consumer TV delivery means, cable, satellite, and VCR, is discussed. Comparisons are made with other proposed ATV (advanced TV) systems. It is concluded that the SC-HDTV system has features that are attractive in all three cases. The minimized interference between SC-HDTV and NTSC (National Television System Committee) allows the assignment of an extra channel (currently taboo) to each broadcast station, permitting simulcasting without rendering obsolete the 160 million NTSC receivers in current use. The low and evenly distributed power of the SC-HDTV signal is of advantage in all media and especially so for the cable operator, both initially and ultimately. Cable also benefits from the possibility of encryption without loss of quality. Satellite and VCR benefit from the improved quality possible with the time-multiplexed format used for frequency modulation. >