Receiver apparatus and method for providing conditional access to received televison programs

Abstract

A television receiver is shown and described for receiving and displaying to a viewer a program content rated television program transmission which includes a data signal. Within the receiver the program content rating, which preferably conforms to the U.S. standard age-based rating and content categories, is derived from the data signal. A viewing control circuit, in response to user inputs, stores one or more program rating viewing authorizations. The derived program rating is compared with the stored viewing authorization for the viewer to develop a blanking control signal. A signal integrity monitoring circuit monitors the signal to provide a rating default control signal in the absence of a reliable program rating signal after a predetermined delay. A blanking circuit, responsive to the blanking control signal and the rating default signal, blanks the program video and mutes the program audio in the event the program level is not authorized to the viewer or the program content rating is not reliable. The rating default control signal may, in one operating mode of the receiver, be applied directly to the blanking circuit to blank the program, or, in another operating mode of the receiver, may, depending on the stored viewing authorization, inhibit the blanking of the program by the first control signal and the rating default signal to allow viewing of the program. In a preferred embodiment, the monitoring circuit monitors the parity error rate in the digital data signal component and provides the control signal when the parity error rate exceeds a predetermined threshold level.