Image Number 5 for United States Patent #7796078.
Compression of signal samples output from a parallel, time-interleaved analog to digital converter (TIADC) for a baseband signal, includes calculating first or higher order differences of consecutive signal samples followed by lossless or lossy encoding of the difference samples to produce compressed samples. Compression of a TIADC output signal with a nonzero center frequency, includes calculating sums or differences of pairs of signal samples separated by an appropriate number of sampling intervals followed by lossless or lossy encoding. The sums or differences of the signal samples have lower magnitudes than the original samples, allowing more efficient compression. Lossy compression alternatives produce compressed data with a fixed bit rate or with a fixed quality in the decompressed samples. Alternatives for lossy compression include attenuating the analog signal before sampling by the TIADC, applying bit shifters or multipliers after sampling to reduce the magnitudes of the signal samples, and lossy encoding.