Abstract: A system and method are provided for determining the broadcast signal source for the signal being displayed by a video wave receiver, whether tuned by the monitored receiver or an associated tuner device, such as a cable converter or video cassette recorder. The monitoring system includes a probe for detecting a horizontal sweep signal of the monitored receiver. The frequency of the detected horizontal sweep signal is determined and compared to stored characteristic frequency values corresponding to the predetermined channels to which the video receiver may be tuned.

Abstract: A system for remotely monitoring or determining the channel to which a voltage tunable receiver (or CATV converter) has been tuned includes an encoder for measuring the magnitude of the tuning voltage applied to the tuning section of the receiver and for generating a channel representative digital code in response to the tuning voltage. The digital code thus generated is compatible with remotely located monitoring equipment, and represents the number of the channel to which the receiver is tuned. Since the tuning voltage is not linearly related to the channel number of the station being received, the encoder utilizes a read-only memory or the like for storing a coded representation relating the channel number to the tuning voltage. In a preferred embodiment, the coded representations are sequentially stored as tuning voltage representations in address locations of the memory corresponding to the respective channel numbers.

Abstract: A system for automatically monitoring the programs broadcast by network affiliated broadcasting stations includes a plurality of remote monitoring sites and a central office for periodically interrogating the remote monitoring sites. Each remote monitoring site contains apparatus for monitoring time varying program identifying data, and for storing the data in a change format when the time varying data changes in an unexpected manner. An elapsed time clock in each remote monitoring unit generates a record of the elapsed time between the unexpected changes.Each remote unit includes a minicomputer having a read-only memory and a random-access memory. The data in the read-only memory serves to establish communications with the central office and permits the central office to access the random-access memory. After the random-access memory has been accessed, it may be reprogrammed to alter the operation of the remote monitoring unit to accommodate different data formats or different information.

Abstract: A system for monitoring the channel to which a remotely located voltage tunable receiver or converter is tuned includes a comparator for comparing the magnitude of the tuning voltage with an internally generated reference voltage to determine the channel number. The reference voltage is generated by a counter driving a linear digital-to-analog converter. The output of the digital-to-analog converter is modified with an analog function generator to provide a piecewise linear approximation of the receiver tuning voltage versus channel number characteristic. A window comparator is utilized to compare the output of the function generator with the tuning voltage and to stop the counter and transfer the contents of the counter to an output circuit when the magnitude of the reference voltage approaches that of the tuning voltage. The contents of the counter at the time the counter is interrupted is indicative of the channel number of the station being received.