Abstract: A device for transmitting sequences of information by modulating a physical quantity includes a transformation unit for transforming sequences of information adapted to associate, with each sequence of information, an intermediate sequence of n intermediate symbols each able to take a first set of different values; a transformation unit for transforming intermediate sequences by taking into account a second set of values whose cardinal number is strictly less than that of the first set, and associating with each element of the first set an element of the second set referred to as a modulator number; and a modulator adapted to modulate the physical quantity by the numbers in each sequence of modulation numbers.

Abstract: For each data element (symbol), a sequence of N points from a QAM constellation is transmitted. If the symbol period is T, then each point in the sequence may have a duration T/N. The sequence is determined by treating the constellation as a finite ring, and repeatedly multiplying the data point by a constant point.

Abstract: The present invention proposes a method and a device for detecting, amongst a set of signals, the presence of a periodic signal of period of occurrence T, in which a signal discriminating the said signal in the said set of signals is delivered. According to the invention, the discrimination signal is sampled in ln samples over more than one period T, a state value B(i) representing its level, and a true correlation value SR is calculated, by cumulating, for pairs of samples i and i+Z, the instantaneous value of correlation between the state value B(i) and the state value B(i+Z), the samples i and i+Z being located at instants shifted by a period T.

Abstract: According to a first aspect, the invention relates to the transmission of an "initial" sequence of at most 2.sup.n numbers, where n is a predetermined natural number, representing binary data modulating a predetermined physical quantity, characterized in that, successively:an "encoding" phase consists of adding to the initial sequence two "coherence" numbers to form a "total transmitted" sequence whose binary data are the subject of the said modulation, the two coherence numbers being determined so that two predetermined "coherence check" combinations applied to a total transmitted sequence each give a predetermined modulo P value, where P is a number more than 2.sup.n,a "decoding" phase consists of applying the said combinations to the numbers of the total received sequence and, where the results of the said combinations are not equal to the said predetermined modulo P values, deducing therefrom that a transmission error has occurred.

Abstract: According to the invention, for the transmission of sequences of information items referred to as "code words", among which sequences referred to as "operative words" are selected, on reception of a signal representing received words, each formed from a sequence of numbers having one of at least three values, and representing a code word, the following are implemented: a function of combining two sequences, one of which is an operative word, the said combination providing a so-called "resultant" sequence; a measurement whereby there is made to correspond to each sequence a real number representing the degree of coherence of the sequence; and, for each word received; at least one sequence resulting from the said received word and from an operative word is calculated iteratively and the said received word is replaced by the said resultant sequence from the moment when the measurement of the degree of coherence of the latter indicates a coherence less than that of the received word, this resultant sequence being