Abstract: A method and system for synchronization of pulse groups without a synchronization signal which comprises selecting a plurality of equal time length coherent processing intervals from a stream of data in the time domain, generally analog data. The data in each of the coherent processing intervals is sampled during each of N equal pulse repetition intervals to provide samples of data, each sampling taking place for an equal portion of the pulse repetition interval. Each of the samples of data is identified according to the position thereof in the associated coherent processing interval. The time domain data is converted to frequency domain data on the basis of the position of the time domain data in the coherent processing interval, all of the samples with the same position in a different coherent processing interval being separately collectively converted.