Deutsche Thomson-brandt Gmbh

Thomson Licensing S.a.

Jinan Lin

Maximilian Erbar

The invention relates to a method for calculating a least mean square algorithm using an N-tap filter. A modified least mean square algorithm is used for the calculation. In a first calculation step, calculation is effected using a first, wide bit width in the N taps. In a second step, depending on the result of the first calculation step, a second, smaller number of bits is selected for the further method steps.

Adaptive filter

The invention relates to a data processing device for recovering digital data which is received in an analogue transmitted signal. According to the invention, the received signal is digitized and a threshold is determined in a threshold estimator. The interference in the channel is corrected in a downstream adaptive equalizer, and a bit clock generator produces the correct sampling rate and phase for the data of a line. The threshold estimator is used to determine the mean value of an input signal for each line, and this value is then taken as the optimum decision value for sampling the data bits for this line. By using an adaptive equalizer, it is possible to correct different types of distortion, caused by the transmission channel, without the need for a training signal. The data processing device according to the invention can thus be used universally for all digital additional signals occurring in a television signal, for example.

Data processing device

For the acquisition of multistandard video data a decoder is used with a register having 24 cells for storing 3 times 8 bit of data. Each of the three bytes are connected with logical devices in order to compare the content of the cells with given start codes. Start of the register is byte , followed by byte and byte . In addition a second 8 bit register is connected in parallel to the register . The content of byte is also fed to a Hamming (8/4) decoder and of byte to a Hamming (8/4) decoder . Each decoder output of 4 bits is fed to the assigned 4 bits of the register , respectively.

Method and apparatus for multistandard video data acquisition

A method for recovering a video signal uses an adaptive equalizer, the characteristics of which are adjusted to the conditions of a transmission channel by using the digital data signals that are concomitantly transmitted in addition to the analogue signal components in a video signal. This adjustment is then used for analogue signal components of the video signals. A teletext signal can advantageously be used for the adjustment.

Method for compensating video signal interferences using concomitantly transmitted digital data

The key component of a digital PAL or NTSC color decoder is a quadrature demodulator for these AM modulated signals. For a SECAM color decoder, however, an FM demodulation is required which is conventionally implemented using a Hilbert filter which is followed by a CORDIC processor and a differentiation stage. It would be advantageous if for multi-standard applications a general-purpose color demodulator for PAL, NTSC and SECAM systems could be implemented on one chip having as much as possible common demodulation processing stages. According to the invention a single common quadrature mixer is used for all three color systems. A resulting bias effect caused by the use of a single mixing frequency is corrected in a clamping stage. The bias effect can also be used for line identification.

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Ottobrun, Germany

Jinan Lin