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1. (EP0862816) METHOD AND DEVICE FOR REMOVING SIGNAL RESIDUES IN QUADRATURE SIGNAL MODULATOR-DEMODULATORS

Office : European Patent Office
Application Number: 96939144 Application Date: 19.11.1996
Publication Number: 0862816 Publication Date: 09.09.1998
Publication Kind : B1
Prior PCT appl.: Application Number:FR1996001824 ; Publication Number: Click to see the data
IPC:
H 03C
H 04B
H03C 1/60
H 03D
H03D 1/24
H04B 1/30
H ELECTRICITY
03
BASIC ELECTRONIC CIRCUITRY
C
MODULATION
1
Amplitude modulation
52
Modulators in which carrier or one sideband is wholly or partially suppressed
60
with one sideband wholly or partially suppressed
H ELECTRICITY
04
ELECTRIC COMMUNICATION TECHNIQUE
B
TRANSMISSION
1
Details of transmission systems, not covered by a single one of groups H04B3/-H04B13/123; Details of transmission systems not characterised by the medium used for transmission
06
Receivers
16
Circuits
30
for homodyne or synchrodyne receivers
H ELECTRICITY
03
BASIC ELECTRONIC CIRCUITRY
C
MODULATION
1
Amplitude modulation
52
Modulators in which carrier or one sideband is wholly or partially suppressed
60
with one sideband wholly or partially suppressed
H ELECTRICITY
03
BASIC ELECTRONIC CIRCUITRY
D
DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
1
Demodulation of amplitude-modulated oscillations
22
Homodyne or synchrodyne circuits
24
for demodulation of signals wherein one sideband or the carrier has been wholly or partially suppressed
H ELECTRICITY
03
BASIC ELECTRONIC CIRCUITRY
D
DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
1
Demodulation of amplitude-modulated oscillations
22
Homodyne or synchrodyne circuits
24
for demodulation of signals wherein one sideband or the carrier has been wholly or partially suppressed
H ELECTRICITY
04
ELECTRIC COMMUNICATION TECHNIQUE
B
TRANSMISSION
1
Details of transmission systems, not covered by a single one of groups H04B3/-H04B13/123; Details of transmission systems not characterised by the medium used for transmission
06
Receivers
16
Circuits
30
for homodyne or synchrodyne receivers
CPC:
H04B 1/302
H03C 1/60
H03D 1/24
Applicants: THOMSON CSF
Inventors: FUCHE LOIC
Priority Data: 9513945 23.11.1995 FR
9601824 19.11.1996 FR
Title: (DE) ELIMINATIONSSCHALTUNG UND -VERFAHREN FÜR RESTSIGNALE VON QUADRATURSIGNALMODULATOREN/-DEMODULATOREN
(EN) METHOD AND DEVICE FOR REMOVING SIGNAL RESIDUES IN QUADRATURE SIGNAL MODULATOR-DEMODULATORS
(FR) PROCEDE ET DISPOSITIF POUR L'ELIMINATION DE RESIDUS DE SIGNAL DANS DES MODULATEURS-DEMODULATEURS DE SIGNAUX EN QUADRATURE
Abstract: front page image
(EN) A method for removing signal residues outside the working frequency band of radio signal transceivers using a quadrature signal modulator-demodulator consisting of two quadrature channels (3, 4), wherein the low-frequency transmit signal applied to the input of the two channels is mixed by a carrier signal from a local oscillator (5). The method comprises shifting the spectrum of the low-frequency transmit signal applied to the quadrature channels, and filtering out (10) the unwanted vestigial band of the spectrum of the output from the two quadrature channels, using a filter with a pass-band set to the working frequency band of the transmitter. The method is useful in SSB transceivers.
(FR) Le procédé a pour but d'éliminer les résidus de signal en dehors de la bande de fréquence utile d'émetteurs-récepteurs de signaux radioélectriques utilisant un modulateur-démodulateur de signaux en quadrature composé de deux voies en quadratures (3, 4) et suivant lesquelles le signal basse fréquence à émettre qui est appliqué à l'entrée des deux voies est mélangé par un signal porteur fourni par un oscillateur local (5). Il consiste à décaler le spectre du signal basse fréquence à transmettre appliqué sur les voies en quadrature et à supprimer par filtrage (10) la bande résiduelle indésirable du spectre du signal obtenu en sortie des deux voies en quadrature par un filtre dont la bande passante est callée sur la bande de fréquence utile de l'émetteur. Application: émetteur-récepteur BLU.
Also published as:
WO/1997/019521