Abstract: A digital television transmitter for an ATSC or NTSC signal includes a digital vestigial sideband modulator having a digital sinusoidal source. A digital multiplier arrangement multiplies a digital signal including the information in the digital television signal by a sequence derived by the digital sinusoidal source to derive plural orthogonally phased digital product signals. A digital lowpass filter arrangement passes low frequency components of the plural digital product signals and rejects high frequency components of the plural digital product signals. A signal combiner arrangement combines a carrier with signals containing information passed by the lowpass filter arrangement necessary to derive a vestigial sideband signal. The combiner arrangement includes at least one digital to analog converter that in different embodiments derives a vestigial sideband signal that modulates an I.F. or R.F. carrier.

Abstract: A reduced bandwidth 8VSB, ATSC transmitter transmits to conventional DTV receivers having bandpass filters with root raised cosine (RRC) band edge responses. The transmitter includes a vestigial sideband modulator for transferring energy in a portion of a spectrum on a first side of a predetermined frequency to a second side of the predetermined frequency. At the low band edge of the spectrum, the predetermined frequency is the pilot carrier frequency. At the high end of the spectrum, the predetermined frequency is the Nyquist sampling frequency. The energy transfer is such that no energy is transmitted between at least one band edge of the spectrum and an intermediate frequency between the band edge and the predetermined frequency. The energy is transferred on a frequency to frequency basis as a function of the energy in the RRC transition and the amplitude of a weighting function extending between the intermediate frequency and the predetermined frequency.