Abstract: An improved method for signal demodulation, based upon the assessment of an error statistic which is independent of the content of the data stream. To determine the appropriate sampling point within a data period, multiple sampling points are utilized to generate a set of alternative decodings of the data stream. Associated with each of these alternative sets is an error statistic which is computed based upon a known characteristic of the transmitted stream. For example, in Differential QPSK, the encoded phase change is known to be a multiple of 90 degrees. The error statistic would be a function of the difference between each sampled phase and the nearest multiple of 90 degrees. This error statistic provides a quantifiable measure of quality and noise margin associated with each sampling point. The decoded stream associated with the error statistic of highest quality is then selected as the proper decoding of the transmitted data stream.

Abstract: A subscriber premise local bus (SPLB) is connected to a cable drop from a wide-band 2-way network through a gateway device providing frequency conversion and blocking of certain frequencies used in the subscriber premises local bus (SPLB). Service channels to the consumer are provided in a first band such as 54 to 750 MHZ, carried unchanged over the SPLB. Return signals from the subscriber are generated at subscriber devices, such as TV, computers, etc. at, or are up-converted to, signals in a higher frequency band, such as 900 to 950 Mhz, for transmission on the SPLB to the gateway device where they are down-converted to frequencies below 54 Mhz for transmission over the network. A band-pass or other filter may block at least some of the lower frequencies from carrying over from the SPLB to the cable drop or 2-way network.

Abstract: A subscriber control system designed to be placed outside of the subscriber's home, for controlling access to cable television signals provided by a cable television headend. The system is modular in design containing a single control module and a single RF distribution module both shared by a number of jammer modules. The jammer modules contain a plurality of frequency agile oscillators, the frequencies of which can be changed in time-multiplex fashion. The outputs of the jammer modules can be shared amongst a number of subscribers using space division switching.

Abstract: A device is disclosed for controlling access to cable television signals. Jamming oscillators are shifted in frequency, jamming multiple services each. The oscillators are shared between multiple subscriber ports, providing a cost effective, high security control system. A modular approach allows security to be added as additional capacity is required.