Compatible and spectrum efficient high definition television

A technique of transmitting high definition television (HDTV) signals on a radio frequency carrier, whereby the transmitted HDTV signals are compatible with television receivers that operate to reproduce standard definition images, and the transmitted HDTV signals are contained within frequency bands or channels in the electromagnetic spectrum allocated for transmission of the standard definition images, comprising the steps of:

• generating an image to be broadcast with high definition source means capable of producing a high definition image frame having a resolution of N lines, wherein N is a positive number equal to about twice the line resolution of a standard definition television image frame, and wherein successive lines n comprising the image frame are consecutively numbered from n=1 to N;
• carrying out said generating step by producing odd line image signals corresponding to each odd numbered line of the image frame and producing even line image signals corresponding to each even numbered line of the image frame;
• modulating the odd line image signals on a radio frequency (RF) carrier wave signal to produce HDTV odd line image signals occupying at most a frequency band or channel that is occupied by the standard definition images;
• modulating the even line image signals on a RF carrier wave signal to produce HDTV even line image signals occupying at most a frequency band or channel that is occupied by the standard definition images;
• establishing a first transmission path;
• establishing a second transmission path coextensive with said first transmission path;
• transmitting the HDTV odd line image signals over the first transmission path;
• simultaneously transmitting the HDTV even line image signals over the second transmission path while the HDTV odd line image signals are transmitted over the first transmission path;
• and
• carrying out said simultaneously transmitting step so that corresponding portions of odd and even line image signals representing adjacent pairs of lines of the generated high definition image frame are transmitted in phase with one another over the first and the second transmission paths.

A technique of transmitting high definition television (HDTV) signals on a radio frequency carrier, whereby the transmitted HDTV signals are compatible with television receivers that operate to reproduce standard definition images, and the transmitted HDTV signals are contained within frequency bands or channels allocated for transmission of the standard definition images, comprising the steps of:

• generating an image to be broadcast with high definition source means capable of producing a high definition image frame having a resolution of N lines, wherein N is a positive number equal to about twice the line resolution of a standard definition television image frame, and wherein successive lines n comprising the image frame are consecutively numbered from n=1 to N;
• carrying out said generating step by producing odd line image signals corresponding to each odd numbered line of the image frame and producing even line image signals corresponding to each even numbered line of the image frame;
• modulating the odd line image signals on a radio frequency (RF) carrier wave signal to produce interlaced HDTV odd line image signals that occupy at most a frequency band or channel occupied by the standard definition images, by
• storing, in first odd field memory means, odd line image signals corresponding to every other odd line n of a generated image progressing from n=1, 5, 9, 13, . . . , wherein n is the line number,
• storing, in second odd field memory means, odd line image signals corresponding to every other odd line of said generated image progressing from n=3, 7, 11, 15, . . . , and
• modulating, during a first odd field, each of the odd line image signals stored in the first odd field memory means in the order of n=1, 5, 9, 13, . . . , on the RF carrier wave signal, and modulating, during a second odd field following said first odd field, each of the odd line image signals stored in the second odd field memory means in the order of n=3, 7, 11, 15, . . . , on the RF carrier wave signal,
• modulating the even line image signals on a RF carrier wave signal to produce interlaced HDTV even line image signals occupying at most a frequency band or channel occupied by the standard definition images, by
• storing, in first even field memory means, even line image signals corresponding to every other even line n of a generated image progressing from n=2, 6, 10, 14, . . . , wherein n is the line number,
• storing, in second even field memory means, even line image signals corresponding to every other even line of said generated image progressing from n=4, 8, 12, 16, . . . ,
• modulating, during a first even field, each of the even line image signals stored in the first even field memory means in the order of n=2, 6, 10, 14, . . . , on the RF carrier wave signal, and modulating, during a second even field following said first even field, each of the even line image signals stored in the second even field memory means in the order of n=4, 8, 12, 16, . . . , on the RF carrier wave signal,
• establishing a first transmission path;
• establishing a second transmission path;
• transmitting the HDTV odd line image signals over the first transmission path;
• and
• transmitting the HDTV even line image signals over the second transmission path;
• whereby, when coupled to said first transmission path, a standard television receiver operating in a 2-field interlaced scanning system will reproduce standard definition frames of the generated high definition image with each frame comprised of odd numbered lines of the high definition image, and, when coupled to said second transmission path, said standard television receiver will reproduce standard definition frames of the generated high definition image with each frame comprised of even numbered lines of the high definition image.