U.S. Philips Corporation

North American Philips Corporation

Philips Electronics North America Corporation

Aravanan Gurusami

Victor J Jacek

Jeffrey L Cox

Thomas P Strong

Robert J Chamberlin

Mark Chapman

Mike Nekhamkin

R Gary Heyman

John G Staiger

Michael Nekhamkin

An improved method for Time Division Multiple Access (TDMA) communications particularly applicable to a network comprising transmitters having significantly different transmission paths to a common receiver. The common receiver measures the response time from each transmitter, relative to a common time reference, then instructs each transmitter to delay all subsequent responses by an amount specific to each transmitter, as determined from these measured response times. This imposed delay results in a more time efficient TDMA protocol, improved error detection capability, and improved security capabilities. This invention is particularly applicable to bi-directional communications to and from a provider of Cable TV, Telephony, and Data Services.

Method and apparatus for improved time division multiple access (TDMA)

A digital finite impulse response (FIR) filter having a shift register for receiving a digital signal, a counter for counting pulses in a sampling signal and a look-up table read-only memory (ROM) having address inputs coupled to the outputs of the stages of the FIR filter and to the outputs from the counter. The output of the ROM forms the filtered signal. This digital filter approach allows for a balance between cost and performance and is inherently flexible due to the programmable nature of its core device (ROM).

Floating point digital transversal filter

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. This invention is particularly well suited for processing small data packets, such as ATM.

Method and apparatus for improved phase shift keyed (PSK) signal

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.

Subscriber return system for CATV full service networks

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. The system features switching utilizing a plurality of series connected diodes to form a transmission line switch and also utilizes filters having inductive elements which are configured by etching processes

Expandable cable television subscriber control system

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.

Growing community of inventors

East Syracuse, NY, United States of America

Aravanan Gurusami