Lsi Logic Corporation

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Adrian Paul Robinson

Oliver Paul Haffenden

Philippe Roger Sadot

Jean-Marc Guyot

Justin David Mitchell

Jonathan Highton Stott

Christopher Keith Perry Clarke

Jonathan Highton Scott

Christopher K P Clarke

Jean Marc Guyot

In order to reduce memory requirements in a chip for demodulating digital video broadcast signals, symbol data values stored for a channel equalisation process have their scattered pilots removed, to achieve a 9% reduction in memory space required. This is achieved by providing a write pointer and a read pointer, the write pointer being arranged to exclude carriers carrying scattered pilots, and the read pointer being arranged to read the stored symbol data, but to add nominal data values at positions of excluded scattered pilots.

Storing digital video broadcast signals

A demodulator suitable for implementation in a single chip for demodulating digital video broadcast signals comprising data modulated on a multiplicity of spaced carrier frequencies, wherein an input broadcast signal is converted to a frequency sufficiently low to enable analog digital conversion of the signal, the demodulator comprising analog to digital conversion means (,) for converting the broadcast signal to a series of digital samples, real to complex conversion means (,) for converting each digital sample to a complex number value, Fourier transform means (,) for analyzing the complex number values to provide a series of signal values for each carrier frequency, frequency control means (,), comprising means responsive to the output of said Fourier Transform means for producing a signal for controlling the frequency of the signal formed by said complex number values, and signal processing means for receiving the signal values and providing an output for decoding, the signal processing means including channel equalization means (,) and channel state information generating means (,).

Demodulating digital video broadcast signals

Apparatus for demodulating digital video broadcast signals with an improved automatic frequency control comprises data modulated on a multiplicity of spaced carrier frequencies, including: analog to digital conversion device for providing a series of digital samples of the broadcast signal, Fourier Transform for analysing the samples to provide a series of data signal values for each carrier frequency signal processing devices for processing the series of data signal values including the phase-error-correcting, and automatic frequency control device for controlling the frequency of the signals input to the Fourier Transform Processor, wherein the automatic frequency control device includes coarse frequency control unit for controlling the frequency in terms of increments of the carrier spacing frequency, and fine frequency control unit for controlling the frequency for values less than a single carrier spacing frequency interval, wherein the coarse frequency unit includes recursive of filtering for assessing a predetermined number (N) of carrier signals on either side of the nominal position of a predetermined continual pilot signal, wherein the outputs of the filter are provided to respective memory locations of a memory, the memory being divided into a plurality of sections, first device for determining within each section a first signal best representing the continual pilot signal, and device means for determining from among the first signals from the plurality of sections, a second signal which best represents the continual pilot signal.

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Sonchamp, France

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