Abstract: A method of detecting and checking the template of digital messages sent to a receiver device includes the encoding beforehand of templates definable by a limited number of parameters. The parameters are detected in the information being received. The stored template matching the parameters detected is determined. The conformity of the information received with the template detected is checked. If this check indicates that the information being received does not conform to the detected template the method returns to the detection step. The method is applicable in particular to receiving asynchronous digital transmissions where it is necessary to check that the information received conforms to one or more modulation templates.

Abstract: A numerical or digital transmission system uses an adaptative coding, of log information, which is sampled and transformed by an orthogonal transformation. The coding has a rate of data flow or delivery, which is reduced by orthogonal transformation with an adaptative threshold. In each scanning field, the binary elements of the coefficients are obtained by a basic coding with a quantification pitch 2S, (S being a whole number either positive or null). A complementary coding is transmitted. The complementary coding is obtained by adding binary elements of weights 2S-1 for each one of the coefficients, until the transmission capacity of the channel is filled. The coefficients are taken in chronological order. The invention is applicable to digital television, but also the coding may be used for transmission of high fidelity sound.