Real time data compression apparatus for a data recorder

An apparatus for real time data compression applied for a data recorder, the apparatus comprising:

• a processing unit for performing a data compressing process;
• an interface unit connected to the processing unit through an interface, adapted to connect to a measuring device to receive measured analog signals from the measuring device, and further including
• a microprocessor;
• and
• an A/D converter converting the measured analog signals to a plurality of data points and transmitting the data points to the microprocessor, and the microprocessor transmitting the data points to the processing unit to be compressed;
• and
• a storing unit connected to the processing unit through data/address bus for storing the compressed data according to a data format;
• wherein the data compressing process performed by the processing unit comprises steps of:
• setting the first data point as a starting point X0;
• sequentially examining the plurality of the data points to determine whether every present data point Xi currently examined is in a predetermined tolerable error range, and a previous data point Xi-1 is ignored if the present data point Xi is in the predetermined tolerable error range;
• recording the previous data point Xi-1 and the total amount of data points accumulated from the starting point X0 to the previous data point Xi-1, and setting the previous data point Xi-1 as a new starting point, when (a) the present data point Xi exceeds the predetermined tolerable error range or (b) the amount of the ignored data points reaches to a first predetermined amount;
• wherein when the data points vary quickly during a period and the amount of the continuously examined data points is less than a second predetermined amount, the total amount of the data points that exceed their respective predetermined tolerable error ranges and the value of each of these data point are recorded;
• wherein the data format for the recorded data points has:
• a main region composed of multiple segments, wherein each segment has a predetermined length and stores
• the value of a presented recorded data point;
• and
• an amount of the data points calculated from a previous recorded data point to the present recorded data point;
• and
• a secondary region recording a start time that the data points are initially recorded, a sampling interval time and multiple blocks, wherein each block corresponds to several segments in the main region and includes a time value and a position value respectively representing a start time of the block and the start position of the block.