Thomson-Csf

Pierre Andr&eacute; Laurent

A process for neutralizing a tube of a high power digital radio broadcasting transmitter includes modulating two quadrature signals I(t), Q(t) at a transmission frequency (F ) by a modulator to control a grid of the tube which is configured to work at saturation with a gain V . A phase-modulated input signal E(t) output from the modulator is amplified by an amplifier which is configured to work at saturation with a gain V . The input signal E(t) is predistorted by digital means so as to compensate for an undesirable coupling between an anode and the grid of the tube of the transmitter so that an output of the transmitter corresponds to a desired output signal S(t). A corrector signal W(t) is calculated using the expression W(t)&equals;jg(t)S(t).

Method for neutralizing a transmitter tube

A process for the construction of LDPC codes including N symbols, of which K are free, each code being defined by a check matrix A including M&equals;N&minus;K rows, N columns, and t nonzero symbols in each column. The method includes allocating the same number of nonzero symbols to all the rows of the check matrix A, taking t to be the smallest possible odd number, defining the columns of A such that any two columns of the check matrix A have at most one nonzero value in a common position, and defining the rows of A such that any two rows of the check matrix A have only one nonzero value in a common position.

Simple and systematic process for constructing and coding LDPC codes

A process for transmitting mixed analog and digital signals. A composite signal is transmitted whose frequency spectrum is composed of a first analog spectrum representative of the amplitude of single-sideband modulation and of a second spectrum composed of multi-subcarriers. The two spectra occupy two disjoint frequency bands. The device may be used for simultaneous broadcast of the same program or its reception by analog or digital receivers.

Growing community of inventors

Bessancourt, France

Pierre André Laurent

Growing community of inventors

Bessancourt, France

Pierre Andr&eacute; Laurent

Pierre André Laurent