摘要:
A method for authenticating appliance messages sent between an appliance and an appliance communication center over an appliance communications network includes maintaining a shared message counter at both the appliance communication center. A shared message counter at both the appliance communication center and the remotely located appliance. An authentication algorithm is applied to the appliance message and the shared message counter to generate an authentication word. The appliance message is then transmitted to the appliance or the communication center along with the authentication word. Upon receiving the appliance message, the appliance or the communication center will apply an authentication algorithm to the appliance message and the shared counter to generate an authentication word. The generated authentication word may be compared to the word received with the appliance message to determine authenticity of the message.
摘要:
A system for short range communications includes a transmitter capable of transmitting a colored noise-like preamble. A receiver receives the colored noise-like preamble and the receiver includes an antenna with an antenna pattern. A direction of the antenna is controllable by the receiver. A signal processor is connected to and responsive to the receiver. The signal processor detects and estimates the strength of the colored noise-like preamble.
摘要:
Appliances (102, 102, 106 and 108) are controlled by providing a source (2016, 112) of command fields (CMD, FIG. 2) that include a context subfield (Community, FIG. 4) defining operating modes and a command subfield (Command, FIG. 4) defining operations to be performed within the context subfield. A network (119) transmits the command fields between the source and the appliance. A controller (112, 116) processes the command fields so that an operation defined by one of the command subfields is performed.
摘要:
The capacity of a Mode-S ADS-B surveillance radar system is increased by sectorizing the radar system by the use of a directional array of Mode-S, quarter wavelength, single element, stub antennas. The ensemble of signals from the array of Mode-S antenna elements is processed electronically. The signal processing/receiver architecture increases the capacity of the Mode-S ADS-B system to be capable of effectively functioning within a highly congested airspace.
摘要:
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.
摘要:
A brevity signaling module for a digital television (DTV) receiver enables the reception of emergency broadcast messages. The overlay signal received at the receiver front end is squared in a squaring loop, producing spectral lines at DC and twice the overlay signal frequency, or 2&ohgr;, where &ohgr;=2&pgr;f and f is the center frequency of the overlay signal. The squared signal is passed through a narrow band filter having a bandwidth sufficient to pass a spectrum containing a plurality of tones 2&ohgr;, 2&ohgr;1, 2&ohgr;2, . . . , 2&ohgr;n, where 2&ohgr;1, 22, . . . , 2&ohgr;n are different frequency tones assigned to different auxiliary functions. The detected tone is used by a control module to determine whether normal multipath processing should be performed or whether this processing should be suppressed and auxiliary functions performed, including turning on the DTV receiver power in order that an emergency broadcast message might be conveyed to persons in the vicinity of the DTV receiver.
摘要:
A digital television (DTV) receiver is provided with a sounder comprising a wideband transmitter and a plurality of wideband receivers having separately located receiving antennas, so that the sounder is, in effect, a bistatic radar system for any given channel, in order to characterize a significant nearby, indoor reflector. A microprocessor receives the timing information generated by the wideband transmitter impulses and the reflected impulse returns to each of the receiving antennas, and calculates a multipath model representing the three-dimensional location of a significant, nearby scatterer.
摘要:
An apparatus detects changes in water vapor above a cooktop surface and includes a radiation source that is positioned below the cooktop surface. The radiation source emits radiation having a predetermined water vapor absorption wavelength. A beam splitter splits the emitted radiation into a first radiation beam and a second radiation beam. The first radiation beam is directed through and above the cooktop surface. A reflective surface positioned above the cooktop surface reflects the first radiation beam. A radiation sensor detects the reflected first radiation beam and generates a sensor output. A reference radiation sensor receives the second radiation beam from the beam splitter and generates a reference output. A processor is connected to the radiation sensor and the reference radiation sensor and receives the sensor output and the reference output. Changes in water vapor above the cooktop surface are determined by analyzing the sensor output and the reference output.
摘要:
A communication system which utilizes the building metal frame as a communication medium is described. More particularly, and in accordance with one embodiment of the present invention, a wire coil is located near to one of the frame pieces so that the coil lays flat in the plane of the building face. A time varying current in the coil creates a time varying magnetic dipole field. This field changes the flux within a “flux window” which is defined as one of the rectangular sections formed by the frame steel members. This changing flux creates a time varying potential around the window, which creates a time varying current that acts in opposition to the induced flux. This current also excites a time varying flux in the neighboring flux windows, which induces time varying fluxes in their neighbors and so on. Generally, a transmit/receive coil is located at each distribution board and relays (“mutter”) the collected readings from one floor to the one below it and so on until all the readings are collected at the basement.
摘要:
A system for directing a receiving lobe of an adaptive antenna array toward an aircraft in flight includes an aircraft position vector calculator and an antenna weight vector generator. The aircraft position vector calculator receives aircraft position information from an aircraft tracking service and calculates, based upon the aircraft position information it receives, an aircraft position vector g. An antenna weight vector generator receives the aircraft position vector g from the aircraft position vector calculator and generates, based upon the aircraft position vector g, an antenna element weight vector w. The antenna weight vector w is applied to the elements of an adaptive antenna array to direct a receiving lobe of the array towards an aircraft in flight.