A system identifies which of first and second signal sources is supplying a program signal to a monitored receiver. The first and second signal sources and the monitored receiver are located in a household. The system extracts a reference program signature representative of an output of the monitored...http://www.google.es/patents/US7774807?utm_source=gb-gplus-sharePatente US7774807 - Source detection apparatus and method for audience measurement
Source detection apparatus and method for audience measurement
