摘要:
A digital transmission system is disclosed having a transmitter (3,6,9) and a receiver (13,16,19) for transmitting a digital signal, such as a digital audio signal, having a given sampling rate F S . The digital signal is subband coded into M subbands with sampling rate reduction. To that purpose the transmitter includes a first unit (3) for splitting up the digital signal into M signals having a sampling rate F S /M. These signals are available at the outputs (4.1 to 4.M) of the first unit (3), and are applied to M analysis filters (6.1 to 6.M), each filter (6.m) having one input (5.m) and two outputs (7.ma and 7.mb). The 2M filter outputs are coupled to 2M inputs (8.1 to 8.2M) of a signal processing unit 9 which has M outputs (10.1 to 10.M) for supplying the M subband signals (S₁ to S M ) Each filter (6.m) is adapted to apply two different filterings on the signal applied to its input and to supply the two different filtered versions of the input signal to its two outputs. The signal processing unit 9 is adapted to supply output signals on each of the M outputs, an output signal being a combination of at least a number of input signals applied to its 2M inputs. On the receiver side a signal processing is carried out which is largely inverse to the signal processing on the transmitter side, in order to realize a signal at the output (21) that is a nearly perfect reconstruction of the input signal.
摘要:
A digital transmission system is disclosed having a transmitter (3,6,9) and a receiver (13,16,19) for transmitting a digital signal, such as a digital audio signal, having a given sampling rate F S . The digital signal is subband coded into M subbands with sampling rate reduction. To that purpose the transmitter includes a first unit (3) for splitting up the digital signal into M signals having a sampling rate F S /M. These signals are available at the outputs (4.1 to 4.M) of the first unit (3), and are applied to M analysis filters (6.1 to 6.M), each filter (6.m) having one input (5.m) and two outputs (7.ma and 7.mb). The 2M filter outputs are coupled to 2M inputs (8.1 to 8.2M) of a signal processing unit 9 which has M outputs (10.1 to 10.M) for supplying the M subband signals (S₁ to S M ). Each filter (6.m) is adapted to apply two different filterings on the signal applied to its input and to supply the two different filtered versions of the input signal to its two outputs. The signal processing unit 9 is adapted to supply output signals on each of the M outputs, an output signal being a combination of at least a number of input signals applied to its 2M inputs. On the receiver side of signal processing is carried out which is largely inverse to the signal processing on the transmitter side, in order to realize a signal at the output (21) that is a nearly perfect reconstruction of the input signal.
摘要:
Dispositif permettant de démultiplexer les paquets d'un signal de type C, D ou D2-MAC/Paquets, comportant des trains successifs de données numériques structurées en paquets affectés à une ou plusieurs composantes de services différentes, chaque paquet ayant chacun un en-tête contenant un numéro de voie, ledit dispositif permettant d'extraire les paquets associés à une ou plusieurs composantes de services données et de les fournir sur des sorties particulières. Il comprend un circuit (49) de génération de toutes les configurations correspondant au numéro de voie sélectionné, des moyens de codage (42) desdites configurations suivant le code de protection contre les erreurs affectant le signal numérique transmis, permettant d'obtenir toutes les configurations codées théoriques d'en-tête correspondantes, des moyens (44) de détermination des distances de Hamming entre l'en-tête reçu et les configurations d'en-têtes codées, et des moyens pour diriger vers un interface de sortie (30) les paquets pour lesquels la distance de Hamming est inférieure ou égale à une valeur déterminée.