Simple algorithms for approximating the complex envelope in terms of real samples
Frank R. Dickey · Proceedings of the IEEE · 1971
The sampled complex envelope of a waveform may be approximated by using linear combinations of two or more successive real samples as complex samples. Simple algorithms are adequate in the case of bandwidths up to about 50 percent. In certain signal processing applications the use of such algorithms permits a reduction in costs by eliminating demodulators.