Thomson Licensing

Thomas Licensing

Raafat Lababidi

Dominique Lo Hine Tong

Ali Louzir

François Baron

Julien Lintignat

Bruno Barelaud

Bernard Jarry

Jean-Luc Robert

All Louzir

The present invention relates to an active band stop filter comprising a filter input and a filter output which are linked by a transmission line LT, a resonator RE coupled to the transmission line and connectable to a load impedance. Between the resonator and the load impedance there is mounted a means of activation of the filtering function in a chosen operating band. The filter is useable in multistandard terminals.

Active band stop filter

The invention relates to a selective active low-pass filter and to a method for improving the selectivity of such a filter. The method includes centering, in the center of a network, the resonant element whose frequency is closest to the cutoff frequency of the filter and in inserting in series with this element a negative resistance of higher value than the parasitic resistance of the filter.

Active low pass filter

The invention relates to a filtering network in HR-Si silicon technology defined by at least one cut-off frequency and comprising an input terminal for receiving the signal to be filtered and an output terminal for delivering a filtered signal. The network comprises a first ground line connected by its ends to first and second ground points connected directly to the ground plane, a second ground line connected via its ends to third and fourth ground points directly connected to the ground plane, a plurality of L/C resonant elements connected in parallel and linked via one end to one of the two ground lines and via the other end between them, by means of coupling inductors which thus create transmission zeros. Each ground line forming inductive elements via inductances the network comprises capacitive elements in series with at least some of said inductive elements, the value of the capacitive elements being selected so that the resonant frequency of the inductive and capacitive elements in series corresponds to a frequency lying outside of the bandwidth.

Filtering network in HR-Si silicon technology

The channel filter includes at a least one basic bandpass filter centred on the frequency of the channel, in series with two cascade-connected reflective filters whose bandwidths are located either side of the basic bandpass filter encompassing the channels adjacent to the channel. A reflective filter can include a 90&#xb0; directional coupler combined with a bandpass filter designed to ensure transfer matched to the load impedance of the coupler with the input of the bandpass filter connected to a directional coupler output port, the input of the directive filter being formed by input port of the coupler and the output of the directive filter being formed by a port recovering the bandpass filter reflection coefficient. The invention applies in particular to the implementation of the DVB-T and DVB-H standards aimed at receiving digital television programs from fixed or mobile multistandard terminals such as mobile telephones, PDAs or other multimedia receivers.

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Rennes, France

Raafat Lababidi