Abstract: VOD services are provided by providing at each subscriber location a switching apparatus (e.g., 23 of FIG. 2) which is remotely controlled from the head end (12) of the system. A set top box of each subscriber is provided with a single channel designation (X) for VOD reception. In response to a request from a subscriber for a particular TV program at a specified time, the provider at the head end actuates the switching apparatus (23) to permit the set top box to be tuned to a specified channel that corresponds to a channel upon which the requested VOD program will be transmitted. Then, when the subscriber selects on his set top box the single VOD channel designation (X), the set top box is capable of receiving the requested TV program on the specific TV channel of the transmission line (11) that has been designated for it by the provider at the head end.

Abstract: An amplitude modulation detection apparatus that includes an envelope detector portion having a pair of diode rectifiers electrically connected at their cathodes which common cathode connection is connected through a series resistor to the input of a low-pass video filter having parallel-connected termination resistors at its output and input of a selected value. A forward biasing circuit that includes a DC voltage source coupled to a low input off-set operational amplifier having its output applied to the pair of diode rectifiers. A third diode rectifier is connected to the input of the operational amplifier at one side and to ground through a series-connected resistor. The series-connected resistor has a value that is determined in accordance with the values of the resistor connected to the commonly connected cathodes and the termination resistors in order to subject the three diode rectifiers to identical operating conditions to obtain optimum temperature compensation.