By Walter S. Ciciora, Ph.D.
nalog television has a long future. Cable will service these large and important markets for may years to come. The compatible inclusion of digital data in analog television signals will increase the value of the spectrum which must continue to serve analog receivers. This data can be used for inputs to computers and for set top boxes which implement “push technology” information services. The technology described makes possible in excess of 4.5 Mbps of data carriage in an analog 6 MHz signal while not interfering with the normal analog reception of television. Data is hidden in a signal in quadrature with the video carrier, amplitude modulation of the sound carrier, and use of the VBI. This has sufficient capacity to convey one, two, or even three MPEG compressed signals to implement the “Compatible Digital Upgrade”.