Patent ID: 7161995

Claim:
A system for determining when a convolutional decoder is out of synchronization with input data the convolutional decoder receives, comprising: a microprocessor, the microprocessor configured to provide a first threshold and a second threshold; a synchronization checker coupled to the convolutional decoder and to the microprocessor, the synchronization checker comprising: a normalization counter coupled to obtain normalizations from the convolutional decoder and configured to accumulatively count normalizations and to output a normalization count; a convolutional encoder coupled to obtain output data from the convolutional decoder and configured to provide convolutional encoded output; first compare logic coupled to obtain the convolutional encoder output from the convolutional encoder and to obtain channel output from the convolutional decoder, the first compare logic configured to compare the convolutional encoder output with the channel output to provide an error output; an error counter coupled to obtain the error output and configured to accumulatively count errors and to output an error count; second compare logic coupled to obtain the normalization count and to obtain the first threshold, the second compare logic configured to compare the normalization count with the first threshold to provide an enable signal; a storage device coupled to obtain the enable signal and the error count, the storage device configured to load the error count in response to the enable signal and to provide loaded error count output; the error counter configured to provide the error count to the storage device responsive to an activation signal from the convolutional decoder, the activation signal and the normalizations from the convolutional decoder being associated, wherein the error count and the normalization count are both initiated responsive to the activation signal; and third compare logic coupled to obtain the second threshold and the loaded error count output, the third compare logic configured to compare the second threshold and the loaded error count output to provide a synchronization indicator output; wherein the synchronization indicator output indicates whether the convolutional decoder is out of synchronization with the input data.