ABSTRAKThe design and construction of eight-bit tune delay autocorrelator is discussed, suitable for use in photon correlation experiments. The sampling time of the correlator can be varied from 1 usec to 100/usec, devide into a number ( typically 256 ) channels (time interval). The instruments records the number of pulses occuring in each sampling time and is stored in location memory in a RAM-BANK. The data is stored in binary form,the data can be converted to analog form by digital to analog converter and is displayed on an oscilloscope.