Image Number 4 for United States Patent #7265793.
A method and system is provided, which may detect digital QAM, VSB and analog TV signals in a faster and more efficient manner than conventional systems. The system and method may be deployed in, for example, cable TV set-top boxes, cable TV modems and television set receivers, which may be coupled to a cable TV or off-the-air terrestrial network. Power measurements of the RF carriers found in a cable TV channel may be utilized to determine whether a digital QAM signal, digital VSB signal, or an analog signal is present in a TV channel. In this regard, it is not necessary for a receiver to demodulate, lock, synchronize, decode and/or validate any video or audio information or digital bit stream in order to detect digital QAM, digital VSB and analog TV signals, or not signal at all. Accordingly, the process of detecting digital QAM, digital VSB and analog TV signals is shortened and simplified.