Abstract: An encrypted program received in an MPEG transport stream is decrypted by receiving an address in the MPEG transport stream, reading a key from a memory in accordance with the received address, and decrypting the encrypted program based on the key.

Abstract: An encrypted program received in an MPEG transport stream is decrypted by receiving a message in the MPEG transport stream, wherein the message contains a key, decrypting the encrypted program based on the key, and replacing the message in the MPEG transport stream with a null packet.

Abstract: In a transmitter, data is encrypted by use of a data key, the data key is encrypted based on a first modification key, and the first modification key is encrypted based on a second modification key such that the first and second modification keys are different keys. The encrypted data, the encrypted data key, and the encrypted first modification key are transmitted to a receiver. In the receiver, the encrypted first modification key, the encrypted data key, and the encrypted data are received from the transmitter. The encrypted first modification key is decrypted based on the second modification key, the encrypted data key is decrypted based on the decrypted first modification key, and the encrypted data is decrypted by use of the decrypted data key.

Abstract: A decision feedback equalizer is operated by making first symbol decisions from an output of the decision feedback equalizer such that the first symbol decisions are characterized by a relatively long processing delay, by making second symbol decisions from the output of the decision feedback equalizer such that the second symbol decisions are characterized by a relatively short processing delay, and by determining tap weights for the decision feedback equalizer based on the first and second symbol decisions. The first symbol decisions may be derived from the output of a long traceback trellis decoder. The second symbol decisions may be derived either from the output of a short traceback trellis decoder or from shorter delay outputs of the long traceback trellis decoder.

Abstract: A timing recovery loop includes a sampler, a narrow band filter, an RMS normalize, a timing error detector, and a sample controller. The sampler samples a received signal. The narrow band filter filters the sampled received signal so as to pass an upper band edge of the received signal and not a lower band edge of the received signal. The RMS normalize sets an average power level of an output of the filter to a substantially constant value. The timing error detector detects a timing error with respect to an output of the RMS normalize. The sample controller controls the sampler in response to the detected timing error.

Abstract: Normally ordered robust VSB data are reordered in accordance with a first interleave to produce reordered robust VSB data. The reordered robust VSB data and ATSC data are reordered in accordance with a second interleave to produce normally ordered robust VSB data and reordered ATSC data. The normally ordered robust VSB data and reordered ATSC data are time multiplexed for transmission to a receiver. The receiver discards the reordered ATSC data or the normally ordered robust VSB data depending upon receiver type or user selection. A robust VSB receiver is able to process the normally ordered robust VSB data upstream of an outer decoder without an interleave thereby avoiding the delay associated with an interleave.

Abstract: An error between the rate fsym at which data are received and the rate fs at which the data are sampled in is determined by processing a received signal with a nonlinear operator, performing a DFT on the processed signal to produce a plurality of DFT bins each characterized by a respective frequency, determining a dominant spectral component k0 from at least two of the DFT bins whose frequencies are substantially close to the frequency of the dominant spectral component k0, and determining the data rate fsym from the dominant spectral component k0.

Abstract: Normally ordered robust VSB data are reordered in accordance with a first interleave to produce reordered robust VSB data. The reordered robust VSB data and ATSC data are reordered in accordance with a second interleave to produce normally ordered robust VSB data and reordered ATSC data. The normally ordered robust VSB data and reordered ATSC data are time multiplexed for transmission to a receiver. The receiver discards the reordered ATSC data or the normally ordered robust VSB data depending upon receiver type or user selection. A robust VSB receiver is able to process the normally ordered robust VSB data upstream of an outer decoder without an interleave thereby avoiding the delay associated with an interleave.

Abstract: Normally ordered robust VSB data are reordered in accordance with a first interleave to produce reordered robust VSB data. The reordered robust VSB data and ATSC data are reordered in accordance with a second interleave to produce normally ordered robust VSB data and reordered ATSC data. The normally ordered robust VSB data and reordered ATSC data are time multiplexed for transmission to a receiver. The receiver discards the reordered ATSC data or the normally ordered robust VSB data depending upon receiver type or user selection. A robust VSB receiver is able to process the normally ordered robust VSB data upstream of an outer decoder without an interleave thereby avoiding the delay associated with an interleave.

Abstract: One embodiment involves encrypting an MPEG transport stream by seeding a random number generator with a seed derived from at least a portion of the MPEG transport stream to produce a random number output. At least one program key and at least one modification key are generated from the random number output. At least portions of the MPEG transport stream are encrypted with the program key. At least one stored key is modified according to the modification key to produce a message segment key. The program key and the modification key are encrypted with the message segment key. The encrypted MPEG transport stream, the encrypted program key, and the encrypted modification key are multiplexed to form a multiplexed output.

Abstract: A timing recovery loop includes a sampler, a narrow band filter, an RMS normalizer, a timing error detector, and a sample controller. The sampler samples a received signal. The narrow band filter filters the sampled received signal so as to pass an upper band edge of the received signal and not a lower band edge of the received signal. The RMS normalizer sets an average power level of an output of the filter to a substantially constant value. The timing error detector detects a timing error with respect to an output of the RMS normalizer. The sample controller controls the sampler in response to the detected timing error.

Abstract: Normally ordered robust VSB data are reordered in accordance with a first interleave to produce reordered robust VSB data. The reordered robust VSB data and ATSC data are reordered in accordance with a second interleave to produce normally ordered robust VSB data and reordered ATSC data. The normally ordered robust VSB data and reordered ATSC data are time multiplexed for transmission to a receiver. The receiver discards the reordered ATSC data or the normally ordered robust VSB data depending upon receiver type or user selection. A robust VSB receiver is able to process the normally ordered robust VSB data upstream of an outer decoder without an interleave thereby avoiding the delay associated with an interleave.

Abstract: A channel impulse response is determined for a channel by receiving a signal from the channel, and by determining a least squares estimate of the channel impulse response. The received signal contains a training sequence and unknown data. The least squares estimate of the channel impulse response is determined by multiplying the received signal by a stored quantity. The stored quantity is based on (i) a stored replica of the training sequence, and (ii) an assumed covariance matrix that is based on a noise variance and an initial channel impulse response that assumes a unit physical channel.

Abstract: A receiver includes an equalizer and a decoder which decodes data from a signal. The signal is based upon an output of the equalizer. The receiver also includes an encoder, which re-encodes the decoded data, and an error generator, which generates an error vector based upon the signal and the encoded data and which weights the error vector according to a reliability that the decoder accurately decoded the data from the signal. A controller controls the equalizer in response to the weighted error vector.

Abstract: At a transmitter, a program is encrypting according to a one program key, the program key is encrypted, and the encrypted program, the encrypted program key, and non-encrypted PSI data to a receiver are transmitted. At a receiver, the encrypted program, the encrypted program key, and the non-encrypted PSI data are received, the encrypted program key is decrypted, the encrypted program is located according to the non-encrypted PSI data, and the located encrypted program is decrypted according to decrypted program key.

Abstract: Normally ordered robust VSB data are reordered in accordance with a first interleave to produce reordered robust VSB data. The reordered robust VSB data and ATSC data are reordered in accordance with a second interleave to produce normally ordered robust VSB data and reordered ATSC data. The normally ordered robust VSB data and reordered ATSC data are time multiplexed for transmission to a receiver. The receiver discards the reordered ATSC data or the normally ordered robust VSB data depending upon receiver type or user selection. A robust VSB receiver is able to process the normally ordered robust VSB data upstream of an outer decoder without an interleave thereby avoiding the delay associated with an interleave.

Abstract: The use of keys to encrypt data in a transmitter and to decrypt encrypted data in a receiver are synchronized in accordance with a synchronization signal that opportunistically replaces a null packet in an MPEG transport stream. Additionally or alternatively, key related information is transmitted and/or received in place of a null packet in the MPEG transport stream and is used to encrypt and/or decrypt data transmitted and/or received in the MPEG transport stream.

Abstract: A decision feedback equalizer has a feedback filter and K feed forward filter branches. Each of the K feed forward filter branches receives an input signal from a corresponding one of a plurality of channels associated with a corresponding one of a plurality of antennas, where K>1. Each of the K feed forward filter branches provides an output. An instantaneous SNR level ?k is determined for each of the K feed forward filter branches. The instantaneous SNR level ?k for each of the K feed forward filter branches is compared to an upper threshold TH and to a lower threshold TL. The outputs from the K feed forward filter branches are selectively added dependent upon the comparing of the instantaneous SNR level ?k for each of the K feed forward filter branches to the upper threshold TH and to the lower threshold TL.

Abstract: Normally ordered robust VSB data are reordered in accordance with a first interleave to produce reordered robust VSB data. The reordered robust VSB data and ATSC data are reordered in accordance with a second interleave to produce normally ordered robust VSB data and reordered ATSC data. The normally ordered robust VSB data and reordered ATSC data are time multiplexed for transmission to a receiver. The receiver discards the reordered ATSC data or the normally ordered robust VSB data depending upon receiver type or user selection. A robust VSB receiver is able to process the normally ordered robust VSB data upstream of an outer decoder without an interleave thereby avoiding the delay associated with an interleave.

Abstract: Program clock references in first and second MPEG data streams are re-stamped in accordance with delays introduced into the first and second MPEG data streams. Accordingly, the program clock references in the first MPEG data stream are re-stamped according to a variable delay in the first MPEG data stream, and the program clock references in the second MPEG data stream are re-stamped according to a variable delay in the second MPEG data stream. The re-stamped program clock references in the second MPEG data stream are corrected according to a fixed delay in the second MPEG data stream. The first and second MPEG data streams are multiplexed, and the multiplexed first and second MPEG data streams are transmitted and received.