Abstract: A received RF signal is down-converted to a baseband or low-IF digitized signal in order to search for a pilot signal that indicates a presence of a DTV signal such as an ATSC DTV signal. The pilot signal characteristically resides in a fixed frequency range for all valid DTV signals and is extracted by processing the baseband or low-IF signal in multiple stages. The first stage reduces signal information to that pertaining to the frequency band covering all valid pilot frequencies, thereby reducing the sampling rate and computational complexity of subsequent operations. A second stage operates on this reduced rate signal to focus on a series of particular pilot frequencies for interrogation. For each such candidate frequency, the cyclostationarity of the signal is measured and tested for statistical significance relative to the background energy to yield an effective test that is invariant with respect to background noise level.

Abstract: Embodiments of the invention may provide systems and methods for detecting the presence a DTV signal such as an ATSC DTV signal. The system and methods may be applied to a received RF signal that has been down-converted to a baseband or low-IF digitized signal. The systems and methods may detect a presence of a DTV signal by searching for its characteristic pilot signal, known to reside in a fixed frequency range for all valid DTV signals. This pilot signal may be extracted by processing the baseband or low-IF signal in multiple stages. The first stage may reduce the signal information to that pertaining to the frequency band covering all valid pilot frequencies and commensurately reduces the sampling rate, and hence computational complexity of subsequent operations. A second stage may then efficiently operate on this reduced rate signal to focus on a series of particular pilot frequencies for interrogation.