Abstract: A method is provided for decimating a digital signal by a factor of M and matching it to a desired channel bandwidth. The method applies the digital signal input samples to a (M?1) stage tapped delay line, downsamples the input samples and the output samples of each tapped delay line stage by a factor of M, and applies each of the M downsampled sample value streams to M allpass IIR filters, respectively. The M allpass IIR filtered sample streams are then summed and scaled by a factor of 1/M. The result can then be filtered by a digital channel filter.

Abstract: A method is provided for decimating a digital signal by a factor of M and matching it to a desired channel bandwidth. The method applies the digital signal input samples to a (M?1) stage tapped delay line, downsamples the input samples and the output samples of each tapped delay line stage by a factor of M, and applies each of the M downsampled sample value streams to M allpass IIR filters, respectively. The M allpass IIR filtered sample streams are then summed and scaled by a factor of 1/M. The result can then be filtered by a digital channel filter.

Abstract: A method is provided for decimating a digital signal by a factor of M and matching it to a desired channel bandwidth. The method applies the digital signal input samples to a (M-1) stage tapped delay line, downsamples the input samples and the output samples of each tapped delay line stage by a factor of M, and applies each of the M downsampled sample value streams to M allpass IIR filters, respectively. The M allpass IIR filtered sample streams are then summed and scaled by a factor of 1/M. The result can then be filtered by a digital channel filter.

Abstract: A method for designing a digital filter, includes: (a) selecting a predetermined number of current sets of coefficients for the digital filter; (b) selecting a metric for evaluating coefficients of the digital filter; (c) computing a metric for each current set of coefficients; (d) deriving a next set of coefficients based on a subset of the current set of coefficients; (e) computing the metric for the next set of coefficients; (f) replacing a selected one of the current set of coefficients based on comparing the metric for the next set of coefficients with the metric for the selected current set of coefficients; and (g) iterating steps (a) to (e) until a termination criterion is met. In one embodiment, the selected metric represents a desired stop band response. The next set of coefficients may be derived by adjusting a first current set of coefficients by a weighted difference between a second current set of coefficients and a third current set of coefficients.

Abstract: Methods and apparatus for the secure and copy-proof distribution of digital content are disclosed. In a preferred embodiment of the invention cryptographic primitives (encryption algorithms, message-authentication codes, hash functions, random-number generators, etc.) are used in a novel security protocol. The invention may be utilized to protect a first-run movie that has been digitized in accordance with one of the current or forthcoming MPEG standards (e.g., MPEG-7). Content receivers or users first register their boxes. This registration information is stored in a secure database. When a subscriber registers, he then receives a box (interface to his player) that has been initialized to contain a number of tamper-proof secrets that are shared between the station and that particular box. The station stores an encrypted version of the digital content. This encrypted version ultimately arrives at some unprotected storage medium local to the player.

Abstract: A frequency domain diversity DVB receiver device includes multiple antenna ports for receiving radio signals, and radio signal processing circuits connected to the antenna ports that convert the received radio signals into digital samples. The digital samples from the different antenna ports time-share a front-end processor which processes the digital samples to provide time-domain symbols. The time-domain symbols are stored in time-domain symbol buffers according to which of the antenna ports the time-domain symbols are received. A fast fourier transform circuit then retrieves the time-domain symbols and converts them frequency-domain symbols, which are then stored one or more frequency-domain symbol buffers according to the antenna ports the corresponding radio signals are received. A diversity processor which combines the frequency-domain symbols from the frequency-domain symbol buffers.

Abstract: Small radio frequency tags for use in a motion capture system include a power source, circuitry for generating radio frequency identification signals, an antenna for transmitting the signals, and means for automatically activating the tags so that the tags begin transmitting the signals including a tag identification code when a cover is removed. The activation means may include a release strip that, when removed, opens or closes an electrical circuit that activates the tag and also exposes an adhesive covered surface of the tag so that the tag can then be adhered to a clothed or unclothed human body or other object to be tracked. The activation means can also include an optical sensor, an oxygen sensor, or other sensors. The battery and the antenna may be printed or constructed of film, thus allowing the tag to be small, thin, and flexible.

Abstract: Methods and apparatus for a high speed wireless communication system are disclosed. The high speed wireless links are accomplished using relatively narrow beams (<1°). These beams are produced using rotational motion at a base station in the center of a cell. In one embodiment of the invention, a radio and an antenna are mounted on a rotating element attached to a vertical mast. In another embodiment, a rotating mirror is employed to produce reflected beams. The present invention may be implemented using the 71-76 GHz, 81-86 GHz, and/or 92-95 GHz frequency bands.

Abstract: A radio frequency (RF) motion capture system includes stationary sensor receivers, one or more transmitter marker tags on one or more objects to be tracked within a capture zone, at least one stationary reference tag transmitter, and a processing system for processing the received signals. The individual tags transmit burst of spread-spectrum RF signals. The transmitted signals include a common sync code, and a tag identification code that is unique to each tag. By computing double differences of pseudoranges, clock terms are cancelled out allowing the processing system to precisely determine the location of each tag as it moves through the capture zone without the need to synchronize clocks between sensors and tags. The system can be used for RF match moving.

Abstract: Methods and apparatus for automatically distributing data and updates to wireless terminals using a point-to-multi-point network is disclosed. In one embodiment, data from a domestic source is conveyed by satellite to a remote location, where the data is then broadcast by a transmitter. The data is automatically pushed to wireless terminals located at remote construction sites around the world.

Abstract: A radio frequency (RF) motion capture system includes stationary sensor receivers, one or more transmitter marker tags on one or more objects to be tracked within a capture zone, at least one stationary reference tag transmitter, and a processing system for processing the received signals. The individual tags transmit burst of spread-spectrum RF signals. The transmitted signals include a common sync code, and a tag identification code that is unique to each tag. By computing double differences of pseudoranges, clock terms are cancelled out allowing the processing system to precisely determine the location of each tag as it moves through the capture zone without the need to synchronize clocks between sensors and tags. The system can be used for RF match moving.

Abstract: Methods and apparatus for gradually delivering software over a terrestrial or satellite network are disclosed. Packets of a software program are conveyed wirelessly from a central server to customers using a portion of standard FM radio or television signals. These packets are conveyed to a wireless receiver at the customer's premises over a relatively long period of time. The packets are slowly accumulated in the customer's receiver, which includes a storage device such as an array of hard drives or memory chips. After this “accumulation period” is completed, and a full software program has been built up, subscribers may then retrieve and use the software. The invention provides a highly secure distribution system which thwarts copyright infringement and other unauthorized copying. In the preferred embodiment of the invention, the data conveyed to customers is computer software, including operating systems, applications and updates.

Abstract: Methods and apparatus for gradually delivering information over a terrestrial or satellite network are disclosed. Packets of information are conveyed wirelessly from a central server to customers using a portion of standard FM radio or television signals. These packets are conveyed to a wireless receiver at the customer's premises over a relatively long period of time. The packets are slowly accumulated in the customer's receiver, which includes a storage device such as an array of hard drives or memory chips. After this “accumulation period” is completed, subscribers may then retrieve and display or use the information. The invention may utilize a stand-alone receiver-storage-printer combination which automatically receives the gradual download, and then periodically prints the information on paper. The invention may be used to convey the full-page text and graphical content of newspapers, magazines, catalogs, manuals, directories or the white or yellow pages.

Abstract: Methods and apparatus for the secure and copy-proof distribution of data are disclosed. In a preferred embodiment of the invention, a network of satellites in low Earth orbit are used to convey packets of data from ground stations to set-top boxes installed in residences. The data is conveyed from the ground stations and to the set-top boxes during times when the network capacity is not fully utilized. In one embodiment, the packets of data which are transmitted from the ground stations to the satellites, and then to the subscribers, are heavily encrypted. In one embodiment, this data is always confined to the secure network, and is never introduced to the Internet or other public networks. The data conveyed by the present invention may be video or audio programming, business data, or any other type of information.

Abstract: Methods and apparatus for the secure and copy-proof distribution of data are disclosed. In a preferred embodiment of the invention, a network of satellites in low Earth orbit are used to convey packets of data from ground stations to set-top boxes installed in residences. The data is conveyed from the ground stations and to the set-top boxes during times when the network capacity is not fully utilized. In one embodiment, the packets of data which are transmitted from the ground stations to the satellites, and then to the subscribers, are heavily encrypted. In one embodiment, this data is always confined to the secure network, and is never introduced to the Internet or other public networks. The data conveyed by the present invention may be video or audio programming, business data, or any other type of information.

Abstract: The Satellite Communication System disclosed in the specification is a dynamic constellation (C) of satellites (S). The present invention is capable of offering continuous voice, data and video service to customers across the globe on the land, on the sea, or in the air. The preferred embodiment of the invention comprises a low Earth orbit satellite system that includes 40 spacecraft (S) traveling in each of 21 orbital planes at an altitude of 700 km (435 miles). This relatively large number of satellites employed by the preferred embodiment was selected to provide continuous coverage of the Earth's surface at a high minimum mask angle (1230a) of forty degrees. Each of the individual 840 spacecraft (S) functions as an independent sovereign switch of equal rank which knows the position of its neighbors, and independently handles traffic without ground control.

Abstract: A communication system and methods for sharing a common communication frequency, without interfering with a second communication system which has a plurality of satellites operating in geostationary orbits (GO) and ground stations (GS) which communicate with the satellites (GEO) on the common communication frequency, is disclosed. Conventional geostationary satellites broadcast in C and K.sub.u bands. Ground stations (GS) which receive these signals must have their antennas pointed toward the plane of the Equator (EQ). Satellites (10) which occupy inclined orbits (LO) and communicate with terrestrial terminals (12) propagate beams of energy that do not intersect the plane of the Earth's Equator. Terrestrial terminals (12) in the northern hemisphere communicate with a satellite (10) only when the sub-satellite point of the satellite (10) is at a latitude more northerly than the terrestrial terminal (12).

Abstract: Earth-fixed cell beam management methods which may be employed to allocate beams generated by a constellation of low Earth orbit satellites (12) flying in orbits below geosynchronous altitudes are disclosed. These beams (19) are electronically steered so that they illuminate "Earth-fixed cells" (26) as opposed to "satellite-fixed cells." Beam steering apparatus using a spherical dielectric lens (106) is disclosed. In a system that employs satellite-fixed cells, the "footprint" of the beams propagated by a spacecraft defines the zone on the ground called a "cell" which is illuminated by the spacecraft. This satellite-fixed cell moves constantly as the spacecraft moves around the globe. In sharp contrast, an "Earth-fixed cell" (26) is a stationary region mapped onto the surface of the Earth (E) that has permanent fixed boundaries, just like a city or a state.

Abstract: A satellite communications system is disclosed. One of the embodiments of the present invention includes six to fourteen satellites (12) which operate in a single Equatorial orbit (14). These satellites (12) are capable of providing communications services to locations on the Earth (E) which are within thirty degrees of the Equator (16). Another embodiment of the invention utilizes both the single Equatorial orbit plane (14) in combination with other satellites (12) moving in polar or inclined orbits (60, 63, 210). The embodiment that combines satellites (12) in Equatorial (14), polar (60) and inclined (63, 210) orbits will provide a wide variety of data services to virtually any point on the globe. In the preferred embodiments, the satellites (12) are designed to operate in a circular low Earth orbit at an altitude of from 800 to 1852 kilometers.