Time-domain equalizer of cascaded filters for VDSL

A device for designing TEQs for different signal bands in a VDSL transmission system, the device for dividing an entire signal band of the VDSL transmission system into at least one low frequency signal band and one high frequency signal band, and obtaining TEQs for respective signal bands, the device comprising:

• fourier transform blocks for modulating respective signal bands;
• an over-sampling means for over sampling signals on the modulated signal band for the low frequency signal band and providing over-sampled signals to a digital-to-analog converter;
• a digital-to-analog converter for converting signals on the modulated signal bands into analog signals and transmitting through a channel;
• an analog-to-digital converter for converting the analog signals transmitted through the channel into digital signals;
• a down-sampling means for down sampling the over-sampled signals converted at the analog-to-digital converter into an original signal;
• and
• means for applying the digital signals to an algorithm for reducing a length of a channel impulse response to obtain the TEQs for the different signal bands,
• wherein the over-sampling means over samples signals on the signal band by ‘k’ times (k=N/m) (where N/2 is the number of entire sub-channels in the VDSL transmission system, and m/2 is the number of sub-channels used), and the down sampling means down samples the over-sampled signals by ‘k’ times before they applied to the algorithm.

A method for designing a TEQ in a VDSL transmission system, comprising the steps of:

• dividing an entire signal band in the VDSL transmission system into at least one low frequency signal band and one high frequency signal band;
• obtaining the TEQs for respective signal bands comprising;
• first step of respectively modulating the divided signal bands before transmission at a transmitter;
• and
• second step of applying respective transmitted signal bands to an algorithm that can reduce a length of a channel impulse response, for obtaining the TEQs for respective signal bands,
• wherein the low frequency signal band signal is over sampled by ‘k’ times (k=N/m) (where, N/2 denotes the number of entire number of sub-channels, and m/2 denotes the number of sub-channels used) at the transmitter before transmitting, and the over sampled signal is ‘k’ times down sampled at the receiver before it applied to the algorithm;
• and
• connecting the TEQs for respective signal bands in series in a time domain.