| 摘要 |
A data compressor for compressing a data signal and a corresponding data decompressor are disclosed. Input data is sent through a high pass predictor filter (10) which generates a signal having a lower entropy. The filtered signal is then sent to encoder (20) but it is also sent via a loop where a control signal for the encoder is generated. The loop comprises a zero count device (30) which generates a signal representative of the proportion of zeros in the filtered signal. The control signal passes through a delay element (35) to a sigma delta generator (40), which generates a control signal having the same average value as the signal it receives but switches between two levels. The two levels are used by the encoder to determine which of the plurality of variable-length compression codes to use to compress the filtered signal. Applications include processing of video and graphics data. |
