Abstract: A recursive on-line wavelet data compression technique which may be used in, for example, a process control network, compresses a stream of data points on-line or in real-time (e.g., as the data arrives or is generated) without requiring the storage of a large amount of uncompressed data. The data compression system includes a data receiver that receives the data points in a sequential manner and a compression tree computation device that determines approximation coefficients and detail coefficients of a multi-layer wavelet compression tree from the received data points. The compression tree computation device determines all of the coefficients of the higher level layers of the compression tree that can be determined after the data receiver receives each of the data points to thereby perform on-line or real-time data compression.