Pieter Fockens

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. >

Intercarrier Buss Phenomena Analysis and Cures

This partly tutorial paper defines buzz as the result of video related incidental phase modulation (IPM) of the intercarrier. The main sources of IPM are 1. parametric and transit time effects, both non-linear in character and 2. AM to PM conversion of a strictly linear character. 1. is the main source of transmitter visual IPM but can also take place in the receiver. Linear AM to PM is prominent in the receiver as Nyquist IPM.

Television Multichan Nel Sound Broadcasting-A Proposal

hInterest in the addition of stereophonic sound to television broadcasts goes back several decades. It was felt by some that the enhancements of black-and-white images by color in the early 1950s should naturally be followed by an enhancement of the sound as had been the development in the motion picture industry. Broadcasting became the focal point of interest after the introduction of the 45/45 LP stereophonic disc in the mid 1950s. As the decade of the 1950s came to a close, the industry organized the National Radio Stereo Committee (NSRC) which was to determine the feasibility of stereophonic transmission for AM Broadcasting, FM Broadcasting, and TV Broadcasting. After an initial flurry of proposals, it soon became apparent that most of the interest was in FM because it was considered the primary high fidelity medium. AM and TV were set aside and the subsequent effort was solely on FM which resulted in the adoption of standards by the Federal Communications Commission for the FM Broadcast Service on April 19, 1961. The standards were based on NSRC systems 4-4a, the Zenith-GE system.

TV Multichannel Sound--Reception and Decoding

High quality stereophonic sound from a television receiver requires improvements in thermal noise performance and in intercarrier buzz, over current practice. Buzz can be reduced by lowering transmitter incidental carrier phase modulation and by receiver Nyquist slope elimination. Buzz due to tuner-caused spurious phase modulation is eliminated through an intercarrier detection process. Nyquist slope elimination is combined with intercarrier detection in the Quasi-split, or quasi-parallel, sound type receiver.1,2 The improvement in noise performance is obtained through dbx companding which also contributes to the reduction of intercarrier buzz and distortion.

A Quadraphonic FM Broadcasting System Incorporating Pilot-Controlled Compression and Pre-Emphasis

Described below is a system for broadcasting a discrete quadraphonic program over a single FM transmitter. The system is compatible with current monophonic and biphonic (stereophonic) broadcasting and also with current SCA service. The system maintains 15 kHz bandwidth for the audio signals.

The digital spectrum-compatible HDTV system

Abstract The system describes a digital high-definition television (HDTV) system designed for US terrestrial broadcasting but friendly to alternate delivery means. The new system, Digital Spectrum Compatible (DSC-)HDTV, is to be simulcast with NTSC during a multi-year transition period, using all existing television bands. DSC-HDTV uses progressively scanned video at three times the current horizontal line rate, compressed to a data rate that fits in a 6 MHz channel using a mix of two- and four-level symbols.

Video encoding in the spectrum-compatible HDTV system

Video compression is achieved in the spectrum-compatible high-definition television (SC-HDTV) system by adaptive transform subband coding. The number of subbands is significantly increased, and the temporal processing is greatly reduced. Coefficients are transmitted as analog data; side information representing adaptation is transmitted as part of the digital data signal. >

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. >

Two Proposed Quadraphonic FM Broadcasting Systems

The Zenith Quadraphonic FM Broadcast Systems (NQRC designations, 2A, 3B) are capable of broadcasting four discrete audio signals and are compatible with existing monophonic and biphonic FM services as well as with the Subsidiary Communication Authorization (SCA) service presently in practice. Two additional subchannels are broadcast in addition to the monophonic channel and the biphonic subchannel to accommodate the additional audio signals. The first of these additional subchannels uses double sideband suppressed carrier (DSBSC) AM modulation and is broadcast in quadrature with the existing biphonic subchannel at 38 kHz. System 2A, utilizing upper single sideband suppressed carrier (SSBSC) AM, broadcasts the second additional subchannel at 76 kHz while system 3B, utilizing vestigial sideband suppressed carrier (VSBSC) AM, broadcasts the second additional subchannel at 90.25 kHz. Both systems provide the necessary spectrum for the existing SCA subchannel centered nominally around 67 kHz. Standard pre-emphasis is employed to broadcast the four discrete audio signals in the band from 50 Hz to 15 kHz. Both systems broadcast an additional pilot subcarrier (at 76 kHz for system 2A and at 90.25 kHz for system 3B) to provide automatic decoder operation for monophonic, biphonic or quadraphonic signals. Sufficient phase linearity is maintained in the baseband spectrum (50 Hz to 91 kHz for system 2A, 50 Hz to 93 kHz for system 3B) to assure adequate separation between the audio outputs.