Abstract: A method and apparatus are provided for determining a particular transmitting station from which program signals are received and translated by a monitored receiver within a test area and including mobile receivers. A stored transmitter characteristic table includes a corresponding transmitting station identification stored with a predefined subarea of a plurality of predefined subareas within the test area for each predetermined tuned frequency of the monitored receiver. A tuned frequency of the monitored receiver is identified and the particular transmitting station corresponding to the identified tuned frequency is identified responsive to both the identified tuned frequency of the monitored receiver and the stored transmitter characteristic table. The identified transmitting station data is stored with time of occurrence data.

Abstract: A co-channel communication system allows transmission of one or more data signals in an active or visible portion of a video raster in a manner that is imperceptible to a viewer. More particularly, the data signal is transmitted over a preselected active video lines of a video raster. In order to reduce the perceptibility of the data signal, the video lines over which the data signal is transmitted is varied according to a random sequence. In an alternate embodiment, the data is also modulated at relatively low modulation levels, for example, by converting the data signal to a spread spectrum signal.