Some recognition algorithms for analogue modulation types - AM, FM. DSB, and SSB - have
been recently developed. In such algorithms, the LSB and USB are considered as one type (SSB). In this paper two fast algorithms for the discrimination between LSB and USB signals are presented. The first algorithm is based on the spectrum symmetrv of the complex envelope of the signal. In the second algorithm. two new signal parameters used to derived the key features are presented. The developed algorithms require less computer storage, and they can be implemented at extremely low cost. Furthermore, they require short segment duration and hence they can be used for on line analysis. The performance evaluation of the developed algorithms were derived from 400 realizations for each of LSB and 'USB signals. II is found that the discrimination with 100% success rate is achieved at 0 dB SNR.