North American Philips Corporation

Other

Philips Electronics North America Corporation

David A Bryan

Carlo Basile

Samir N Hulyalkar

Mikhail Tsinberg

Alan P Cavallerano

Faramarz Azadegan

Aldo G Cugnini

Yo-Sung Ho

Zhi-Yuan Guan

A method and apparatus for transmitting a digital television signal using a first multipoint constellation comprised of a plurality of identical second constellations each having fewer points than the first constellation and each positioned in a different section of the first constellation. The receiver includes a decoder which decodes data as encoded in one of the second constellations. Additional bits, transmitted with the data, are also decoded at the receiver to identify which to section of the first constellation the second constellation belongs.

Method and apparatus for communicating digital television signals using

A method and apparatus for transmitting a digital television signal using a single QAM (quadrature amplitude modulated) carrier which provides audio and video data packets at respective complex symbol data rate levels. One purpose of the invention is to provide a digital television signal which resembles the audio vs. video reception characteristics exhibited by conventional analog television (i.e. NTSC). way communication path.

Multiplexed modulation system for robust audio digital television

A method and apparatus for modulating and demodulating an MCM television signal is described which is particularly useful in proposed 'simulcast' HDTV terrestrial broadcasting. The MCM spectrum of the television signal is shaped using weighting coefficients which are derived from either an idealized NTSC signal or an actual NTSC co-channel signal. These coefficients are used to shape the respective MCM carriers to provide an energy distribution in the MCM signal which provides greater degree of robustness with a minimum degree of co-channel interference to and from an NTSC co-channel signal. The instant invention further takes advantage of the interference characteristics of composite television signals described above, to position the placement of the MCM carriers in frequency, to minimize interference with an NTSC co-channel signal. Several methods of deriving the weighting coefficients are described including an adaptive approach whereby the characteristics of the interfering NTSC transmission are received and the instantaneous NTSC spectrum calculated therefrom and weighting coefficients assigned accordingly. These coefficients can be transmitted to a receiver to update its coefficient table.

Method and apparatus for transmission and reception of a digital

A method and apparatus for encoding a television source signal having a first bandwidth, into a frequency multiplexed signal having a narrower bandwidth and comprising a plurality of subcarriers modulated with digital information. Each of said subcarriers has an amplitude, bandwidth and coding characteristic which reflects the relative importance of the digital information provided thereby. The frequency multiplexed signal is suitable for use in a broadcasting environment wherein a conventional television signal is also used and wherein said subcarriers are disposed in frequency, in positions which are least likely to result in interference to or from said conventional signal. The invention also includes a receiver for decoding the frequency multiplexed signal and for providing a high definition display.

Method and apparatus for the transmission and reception of a

Growing community of inventors

Danbury, CT, United States of America

David A Bryan