Abstract: A geometric harmonic modulation (GHM) communication system communicates GHM signals on a power line of a reconfigurable network. The GHM communication system includes a master controller connected to the power line for transmitting GHM signals on the power line. A boundary component is also connected to the power line. A GHM addressable device is connected to the power line between the master controller and the boundary component. The GHM addressable device defines a boundary of a network region based on the GHM signals transmitted over the power line.

Abstract: A communication system includes a transmitter configured to pulse shape a GHM signal to confine the frequency spectrum of the GHM signal within a predefined frequency range. A receiver is also included that receives the transmitted GHM signal. The receiver includes a processor for maximizing the GHM signal to noise ratio and minimizing the bit error rate. The GHM signals are also synchronized to establish a relative time for correct interpretation of bit positions.

Abstract: A system for spread spectrum power line communications employs a harmonic modulation (HM) transmitter coupled to the power line for transmitting message bits to an HM receiver. The spread spectrum accommodates a plurality of HM transmitters simultaneously occupying the same bandwidth. The spectrum of HM, in a frequency range above 60 Hz but below the maximum frequency that will carry through a distribution transformer, is ideal in combating carrier synchronous noise since it can be interleaved with the noise harmonics and therefore be effectively spectrally disjoint with the synchronous noise process spectrum.

Abstract: In a time division multiple access spacecraft communication system, each ground station determines when to send its information packets to arrive at the spacecraft at the beginning of a time slot. The calculation is based upon knowledge of the location of the spacecraft. A master ground station determines the location of the spacecraft by the use of the propagation delays between the various ground stations (including itself) and the spacecraft, together with knowledge of the locations of the ground stations. The spacecraft location is then transmitted back to the various ground stations. The determination of propagation delay by each ground station is performed in two major steps. The first step determines coarse time delay to within one bit interval by repeatedly transmitting a multibit unique word to the spacecraft, and counting bits until the next unique word is received from the spacecraft.

Abstract: A system for communicating digital information over wires having a great deal of harmonic distortion, such as a power line, employs a transmitter which transmitter which creates a carrier wave for each of a plurality of signals to be sent. This carrier wave has frequency lobes positioned between the frequency lobes of the harmonic distortion. Each of the lobes of a single carrier signal is encoded with the same bit value during a given bit period. This signal is then mixed with any existing signal on the wire. At a remote receiver coupled to the wires, the signal is sensed, filtered, and Fourier transformed into coefficients. The signal-to-noise (S/N) ratio of each Fourier coefficient is determined by a novel S/N estimation technique. The coefficients are weighted based upon the S/N ratio estimation, and decoded, preferably by an inner product of the weighted Fourier coefficients. Additionally, the S/N ratio estimates could be time averaged before being used in the weighting and bit decoding.