A system for transmitting digital programming includes a program source providing digital information, circuitry for modulating the digital information onto a visual carrier modulated with analog television programming, and a visual transmitter coupled to the modulating circuitry. Using a phase modulation method, the system phase modulates the digital information onto a visual carrier, reduces the baseband frequencies of the phase modulated visual carrier, and amplitude modulates the phase-modulated video carrier onto a video signal. The amplified and encoded video signal are combined with an amplified sound signal and transmitted. Using an additive method, the system modulates the sidebands of the video carrier with the digital information and amplitude modulates the video signal onto the video carrier. The data-modulated sidebands are phase-shifted such that they will be in quadrature with the amplitude-modulated video signal. The system combines the amplitude-modulated video carrier and the data-modulated quadrature sidebands. With a blended multiplicative/additive method, the system provides phase modulation and quadrature sideband addition to provide an optimized result.

Expanded information capacity for existing communication transmission systems

Signal processors for permitting the transparent, simultaneous transmission and reception of a data signal in the video bandwidth is disclosed. The signal processor in the transmitter rasterizes the data at the horizontal scanning rate and modulates the data with a data carrier at a non-integral multiple of the horizontal scanning rate to obtain frequency interleaving. The data is transmitted during the active video portion of each video line.

Data with video transmitter

The invention is related to methods and apparatus that can advantageously alter a playback rate of a multimedia presentation, such as a video clip. One embodiment of the invention permits a multimedia presentation to be sped up or slowed down with a controlled change in pitch of the sped up or slowed down audio. In one embodiment, this controlled change in the pitch permits the sped up or slowed down audio to retain a same sounding pitch as at normal playback speeds. In one embodiment, a duration is specified and playback of the video clip is advantageously sped to complete playback within the specified duration. In another embodiment, a finish by a time is specified, and the playback of the video clip is advantageously sped to complete playback by the specified time.

Systems and methods for multimedia time stretching

Signal processors for permitting the transparent, simultaneous transmission and reception of a secondary data signal with a video signal in the video band is disclosed. The signal processor in the transmitter rasterizes the data at the horizontal scanning rate and modulates the data with a data carrier at a non-integral multiple of the horizontal scanning rate to obtain frequency interleaving. The data is transmitted during the active video portion of each video line.

System for transparent transmission and reception of a secondary data signal with a video signal in the video band

A secondary signal is processed and injected into a primary video signal. The injection level of the secondary signal is dynamically controlled to reduce transmission errors in the secondary signal, and to minimize interference and power level limitations. The injection level of the secondary signal may be based on video analysis of the primary signal or on error information fed back from a receiver which receives the transmitted secondary signal.

Transmitting a secondary signal with dynamic injection level control

Extended definition television (EDTV) signals including a compatible composite wideband signal and a separate helper or extended definition signal are combined, for example, for recording purposes, using frequency multiplexing techniques. The helper signal is applied to a modulator, which produces a suppressed carrier modulated signal, to frequency shift the helper signal to a spectral band above the frequency band occupied by the compatible composite wideband signal. The frequency shifted and wideband signal are then added to form the combined signal.

Walter James Morgan

Papers

Edtv recording apparatus