Implementation of a Secure Pay DBS System with Billing in the Receiver

INTRODUCTION Ever since the first geo-stationary satellite capable of transmitting a video signal was put into orbit, it has been only a matter of time until the beginning of DBS. Early engineering concern centred on the determination of the energy per unit area required on the Earth's surface, and the feasibility of providing that energy from the space segment. Calculations were based on the assumption of using the existing video formats in place around the world. It was then suggested in Europe that, for various reasons, the existing formats might not be optimum, and an alternative format was suggested. One important factor, as we 1 1 as the poor match of composite signals to the triangular noise spectrum of a demodulated F.M. signal, was the implicit international nature of satellite broadcasting. International 'leakage' of TV signals is inevitable to a degree far exceeding that in terrestrial broadcasting. To take advantage of this overspill, a common format across Europe could be of benefit. This work led to the selection of MAC as the European video standard for DBS. While these deliberations were proceeding in Europe, American broadcasters were investigating the possibility of rationalising the means of payment fox TV programming. The multiplicity of channels available with Cable TV and, potentially, DBS can only dilute the advertising revenue pool, spreading the income more and more thinly between broadcasters. There comes a time when indirect payment for TV entertainment breaks down, and direct payment must be used. The problem is, how to know whether a viewer has watched a particular programme, in order to exact payment.