Narrow bandwidth television

Overview

Narrow band television (or NBTV) is an analog mode that uses 30 and the NTSC color standard in an SSTV like format.

NBSC format

NBSC is NBTV+NTSC. It uses YUV color.

Modulation

NBTV is separated YUV or IQ (color components), it has three signals that are compatible with black and white receivers. The Y signal is the same original B+W signal. To handle the UV (or IQ) signals, the NTSC (and PAL) systems use Quadrature Amplitude Modulation (QAM). Quadrature modulation uses two carriers at a phase of 90 degrees. This is modulated by the UV signal so that if the UV is zero the output is zero but if it is negative then it is modulated “upside down”.