Abstract: The subject matter of this application concerns directional slot antenna suitable for very high frequencies. The antenna is made up from a wave guide closed at one end on a terminal absorption load. One face of the wave guide is characterized by an elongated slot of consistent width which is formed in relation to the remainder of the wave guide according to a prescribed mathematical relationship.
Type:
Grant
Filed:
May 25, 1965
Date of Patent:
August 31, 1976
Assignee:
Telecommunications Radioelectriques et Telephoniques T.R.T.
Abstract: An arrangement for digitally processing a given number of analog channel signals, more particularly a digital multiplexer and demultiplexer provided with a number of signal paths each comprising a recursive digital filter and delay circuits arranged in cascade therewith, said filter circuits having an amplitude-frequency characteristic of a lowpass filter having a cut-off frequency which is equal to half the bandwidth of a channel signal and a phase-frequency characteristic which is such that the difference between such a phase-frequency characteristic and the phase-frequency characteristic of a reference digital filter has a sawtooth-shaped variation, the slope of the sawtooth being opposite to the slope of the cooperating delay circuit. The arrangement furthermore comprises in cascade a discrete Fourier transformer connected to the signal paths.
Type:
Grant
Filed:
November 29, 1974
Date of Patent:
July 27, 1976
Assignee:
Telecommunications Radioelectriques et Telephoniques T.R.T.
Inventors:
Maurice Georges Bellanger, Jacques Lucien Daguet
Abstract: An arrangement for simultaneously producing signals having a decreasing frequency and signals having an increasing frequency. In this arrangement the signals have frequencies which are complementary relative to the double value of a central frequency. The arrangement includes a pair of voltage-controlled oscillators controlled by signals supplied by a control generator. The arrangement is characterized in that for each oscillator there is provided with a phase control loop and that the control generator is of the digital type designed to supply two pairs of digital signals. One pair is applied to the frequency dividers and the other is applied to the oscillators so as to tune them to such a frequency that they are in the operating range of the phase control loop.Use: Radio-electric transmission of data.
Type:
Grant
Filed:
December 19, 1974
Date of Patent:
June 8, 1976
Assignee:
Telecommunications Radioelectriques et Telephoniques T.R.T.
Abstract: A speech transmission system employing a semi-vocoder comprising a spectral analyzer and a spectral synthesizer for the upper frequency range of the speech signal. The speech signal in the low frequency range base band is transmitted by using delta modulation and the delta-modulated base band signal is used directly in the receiver as a voice excitation signal for the spectral synthesizer.
Type:
Grant
Filed:
July 18, 1974
Date of Patent:
April 20, 1976
Assignees:
Telecommunications Radioelectriques et Telephoniques T.R.T., Etat Francais
Inventors:
Guy Albert Jules David, Gilbert Marie Marcel Ferrieu, Pierre Lorand, Michel Cartier