Digital modem transmitter

Abstract

A data modulator for transmitting a first sequence of data symbols at a symbol rate of 1/T, the modulator being characterized as having a carrier frequency of f.sub.c Hz and the data symbols being denoted as x(kT), where x(kT) is a real or complex number and k is the time index of the kth symbol, featuring, in one aspect, modulated signal generating means for receiving the first sequence and generating, in response thereto and at the symbol rate, a second sequence of complex-valued signals y(kT), the signal y(kT) representing the complex number y(kT)=x(kT).multidot.exp (j2.pi.f.sub.c kT), where j=.sqroot.-1, and filter means for receiving the second sequence and generating, in response thereto, a third sequence of real-valued signals, at a rate higher than the symbol rate, the third sequence representing linear combinations of the real and imaginary parts of the second sequence of complex-valued signals y(kT).

Dependencies are inferred from the claim text.