Texas Instruments Corporation

Zoran Microelectronics Ltd.

Arvind Lonkar

Manoneet Singh

Jerry Krinock

Kumar Satyanarayana Hebbalalu

Oscar Ayzenberg

Method and apparatus for OFDM synchronization and channel estimation. In a temporal embodiment, received embedded system pilot symbols are inverse Fourier transformed at expected index locations and correlated with computed complex conjugates of inverse Fourier transforms of pilot symbols for providing a correlation function for the channel impulse response. In a frequency domain embodiment, embedded system pilot symbols are augmented with pilot-spaced inferred guard band symbols, multiplied by scaled complex conjugates of computed pilot systems, and inverse Fourier transformed into the channel impulse response. Time and frequency are synchronized in feedback loops from information in the channel impulse response. The channel impulse response is filtered, interpolated, and then Fourier transformed for determining channel estimates for equalization.

Method and apparatus for multicarrier channel estimation and synchronization using pilot sequences

Recovering data (e.g., closed captioning data, teletext data) encoded in television signals. A line encoding the data is over-sampled. The resulting samples are examined to determine the average number of samples spanning the low and high values in a run-in period. The average numbers are used to determine the sampling clock and the samples which represent the encoded data. By using the two average numbers, any errors which may be otherwise encountered due to factors such as ghosting may be eliminated or avoided.

Recovering data encoded in television signals

A circuit for recovering the data encoded in several VBI channels without requiring a large number of gates. An analog to digital converter (ADC) and a clock and data recovery circuit may be associated with one of several possible channels. ADC over samples each VBI channel, and clock and data recovery circuit determines which subset of the over samples represent the encoded data by examining the over sampled samples. The selected subset may be stored in a shared memory and a equalizer may process the subset of samples of all channels to perform tasks such as deghosting. Due to the shared equalizer, the number of required gates may be minimized.

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Santa Clara, CA, United States of America

Arvind Lonkar