Abstract: The baseband portion x(t) of a voice signal is first applied to a complex filter which provides a couple of signal components y and y in quadrature with each other. Each of the components y and y is then fed to a bank of QMF filters which split the spectra of y and y into N subbands providing subband components y.sub.i and y.sub.i (with i=1, 2, . . . , N), respectively. The subband components y.sub.i and y.sub.i are combined together to generate information representative of the phase (.phi..sub.i) and amplitude (.rho..sub.i) of the contents of each subband, which information is then transcoded by a coder which dynamically distributes the available bit resources to the various subbands.

Abstract: The method allows voice and data information to be concentrated over a reduced number of telephone lines. It consists mainly in processing each voice signal to extract therefrom a so-called analog base band signal and digitally coded characteristic parameters. Said parameters are then multiplexed with pure data and submitted to a modulation operation. The analog signal resulting from the modulation is then added to the base band before being transmitted over a telephone line.

Abstract: A digital filter is described which is based on the use of the so-called primitive roots transform and its inverse. This transform converts a series of binary numbers {a.sub.n } into a transformed series ##EQU1## WHERE G IS A PRIMITIVE ROOT OF A PRIME NUMBER P, AND THE VALUES BETWEEN SUPERFLUOUS PARENTHESES ARE TAKEN MODULO P. Said filter is provided with input means for applying fixed length data blocks made of a group of input samples appended with an equal number of zeros to the input of at least one circular convolutor. This convolutor is provided with accumulating means for generating multiples of each a.sub.n term, adding means for generating said A.sub.k terms by adding successively provided multiples of a.sub.n to selected partial terms of A.sub.k, and means for storing said partial A.sub.k terms as they are formed. There is also a device for storing the Primitive Roots transform B.sub.

Abstract: A decision feedback equalizer is described wherein an approximate value .alpha..sub.0 of the phase of the signal being received at sampling time t.sub.0 is obtained by subtracting a phase error (.theta..sub.0 - .alpha..sub.0) from the value .theta..sub.0 of the phase of the signal received at t.sub.0. Value .DELTA..sub.0 is fed to a decision logic which provides an estimated value .DELTA..sub.0 of the phase of the transmitted signal, which value is representative of the detected data. Value .alpha..sub.0 is fed to a decoder which provides its components in a Cartesian coordinates system. These components are fed to the inputs of a complex, cross-coupled equalizer which supplies the approximate values .DELTA.u.sub.0 and .DELTA.v.sub.O of the components, in a Cartesian coordinates system, of the distorting signal representative of all distortions introduced by the communication channel. The phase error (.theta..sub.0 - .alpha..sub.0) is obtained from the relationsin (.theta..sub.0 - .alpha..sub.0) = .DELTA.u.