An optical system spatially modulates three individual primarycolor images onto a common spatial carrier frequency with 120* phase separation. Electron beam scanning of a single tube converts the spatially modulated image to an electrical output signal composed of an average value and a chrominance signal consisting of three modulated waves at a single electrical color carrier frequency separated in phase by 120*. Since the scan velocity varies, the frequency of the electrical color carrier is modulated by the velocity. A signal having the same modulation is used as a reference for phase demodulation of the chrominance signal to produce three individual components. The average value of the output signal, which represents the monochrome, is combined with each of the individual components to form three independent signals, each representative of one of the primary images. The phase demodulation technique requires substantially lower spatial resolution than time sequential or frequency separation schemes, and the specific 120* spatial phase separation of the image components insures against hue shift due to variations in the tube''s aperture response.