Vestigial sideband modulation system - has two channels, with data bits with even index always applied to one channel and those with odd index to other one

摘要

The system uses a sine channel and an orthogonal cosine channel, each containing a filter. The output signal of one filter is directly multiplied by an oscillator signal the output signal of the other one by an oscillator signal shifted by 90 deg. The output signals of both channels are added to each other. Data bits with an even index are always applied to one channel, and data bits with an odd index always to the other channel. The data bits fed into both channels are provided with a sign alternating from bit to bit. The filters are indentical and change data with the same elementary symbol z(t) as a real function of time into their respective sidebands, the frequency of the osiclator is shifted wrt the carrier frequency proper fT by alpha B)/2, where B is the (-6db) bandwidth of the elementary symbol z(t), or of the transmission systems, and alpha a selectable parameter.