Patent ID: 8456530

Claim:
A system for detecting a digital TV signal emitted into free space from the coaxial cable portion of an HFC network, said system operating in connection with a time reference signal, a timestamp, and a communications link, the digital TV signal being transmitted in the HFC network from a headend, said system comprising: a headend unit, including— an input, adapted to be coupled to the headend, for receiving the digital TV signal from the headend for use as a TV reference signal, a first receiver for receiving the time reference signal and timestamp, a first signal sampler, coupled to the input and the first receiver, for sampling the TV reference signal at a rate corresponding to the time reference signal, to produce TV reference signal samples, a first data processor, coupled to the first signal sampler for receiving the TV reference signal samples, and coupled to the first receiver for receiving the timestamp, said first data processor being adapted to associate the timestamp with the TV reference signal samples, and a first communications interface, associated with the first data processor and adapted to interface with the communications link for transmission of the TV reference signal samples and the associated timestamp over the communications link; and a detector unit, including— an antenna for receiving the digital TV signal emitted in free space from the coaxial portion of the HFC network, for detection as a TV leakage signal, a second receiver for receiving the time reference signal and timestamp, a second signal sampler, coupled to the antenna and the second receiver, for sampling the TV leakage signal at a rate corresponding to the time reference signal, to produce TV leakage signal samples, a second data processor, coupled to the second signal sampler for receiving the TV leakage signal samples, and coupled to the second receiver for receiving the timestamp, said second data processor being adapted to associate the timestamp with the TV leakage signal samples, a second communications interface associated with the second data processor and adapted to interface with the communications link for reception of the TV reference signal samples and the associated timestamp from the communications link, and adapted to transfer the TV reference signal samples and the associated timestamp to the second data processor, and a cross-correlation processor, coupled to the second data processor and adapted to perform a cross-correlation of the TV reference signal samples, associated with the timestamp, with the TV leakage signal samples, associated with the same timestamp, to produce a cross-correlation function having a peak, whereby the TV leakage signal is detected from the peak of the cross-correlation function.