To provide a transmitting apparatus for particularly realizing the compatibility of NTSC broadcasting and HDTV broadcasting in satellite broadcasting and for remarkably reducing unreceivable zones within service areas of ground broadcasting in a transmitting apparatus in which a carrier is modulated to transmit a digital signal.

The transmitting apparatus is equipped with a modulation part for modulating a first data stream to generate a first modulated signal and for modulating a second data stream to generate a second modulated signal. The first data stream has demodulating information for demodulating the second modulated signal. An NTSC signal is then transmitted as the first data stream and a differential signal of HDTV and NTSC is transmitted as the second data stream, such that when the same signal from the transmitting apparatus is received, a receiver having a large antenna and a multi-level demodulation capability can demodulate the first data stream and the second data stream. At the same time, a receiver having a miniaturized antenna and a low-level demodulation capability can receive the first data stream. Thus, a transmission system having compatibility is constructed.