RU94015300A - METHOD OF TRANSMITTING AND RECEIVING A WIDE-SCREEN TELEVISION IMAGE - Google Patents

Claims (1)

A method for transmitting and receiving a wide-screen color image (the SECAM-plus system) is proposed, in which two down conversions of the line standard of the original wide-format image are performed on the transmitting side. One of the transformations reduces the number of rows to 3/4 from the original. The received main signal is encoded according to the SECAM standard and creates a widescreen color image with a reduced number of active lines on the screens of SECAM conventional televisions. The second transformation generates an auxiliary signal carrying information about the high-frequency vertical components of the original image and containing 1/4 of the original number of rows. The auxiliary signal modulates the SECAM color subcarriers in amplitude and is transmitted in the upper and lower parts of the raster. This signal is not reproduced on the SECAM standard TV screen (in the brightness channel, the color subcarriers are suppressed by a notch filter, in the color channel, amplitude modulation is cut off by limiters, and since the subcarriers are not modulated in frequency, the parasitic color is not obtained). The raster sections where the auxiliary signal is transmitted have the form of black bars. Due to the phase switching of the subcarriers, the auxiliary signal does not create interference on the screen of a black and white TV. In a special widescreen TV, SECAM-plus, the main and auxiliary signals are demodulated and undergo up-conversion of the line standard. After that, the auxiliary signal is combined with the luminance component of the main one. As a result, the TV screen produces a widescreen color image with full vertical clarity.