摘要:
An apparatus for snubbing or blanking digital signals representing a band of signals that includes an encoded carrier signal transmitted over a power line. An average signal level (SNAVG) is compared with the instantaneous signal level to develop a blanking circuit control signal (SNGT). Additionally, snubbing occurs in the circuit (24) which determines the average signal level, to prevent noise from building up the average signal level. A hold-off signal (SNHO) is used in this circuit to prevent the average signal level (SNAVG) from being latched permanently low. A unique infinite impulse filter (17) subtracts out the D.C. offset, thereby improving the dynamic range of the blanking. Additionally, the average signal level (SNAVG) is used by AGC logic (25) to control the gain at the front end (14) of the apparatus. The state and switching of the AGC is controlled to minimize errors.
摘要:
A power line communications analyzer (PLCA) providing a signal strength metering system and selectable signal attenuation functions and a means for adjusting the transmitting unit's attenuation and measuring error rate without the need for a user to be present at both the sending and receiving locations under test is disclosed. Each PLCA is coupled to a power line communication network via an electrical outlet and power lines. In actual operation, one of the PLCAs acts as a data transmitter and the other PLCA acts as a data receiver. The mode of operation of the PLCA can be dynamically altered during operation of the system. The PLCA comprises control logic that receives command inputs from a keypad, generates data packets for transmission on the power line communication network, receives and analyzes data packets received from the power line communication network, detects the power line signal and/or noise level and drives the LED display accordingly, and displays packet transmission information on an LCD display.
摘要:
An improved meter and its operation is described. The meter can be a part of a larger automated meter reading process that allows for remote reading of the meter though power line communication. Using a microcomputer core, the meter processes incoming analog data and can calculate several relevant data values need by utility providers. The meter can also be used to monitor and detect tampering dry connect/voltage free devices, such as gas and water meters, connected to the meter.
摘要:
A module (10) for interconnecting an AC power line (15) to a load (11) such as a lamp, which includes a first switch (12). The module (10) detects the state of the first switch (12) and then provides power to the load (11) when the switch is closed. Sequentially opening and closing the first switch (12) can be used as a command to dim the lamp. The module may also include a transceiver (20) which communicates the state of the switch to the other modules thereby allowing a plurality of devices to be controlled by the first switch (12).
摘要:
A method and means for recovering data in a spread spectrum communications system (100). The present invention includes a method and means for providing a sync window time period. The sync window is set to encompass the correlation values which are generated one baud time from the previous recovered data bit. The present invention also determines the peak correlation value within the sync window and the location in time within the sync window that the peak correlation value occurs. The present invention also provides a polarity window time period. The polarity window occurs during the sync window. The present invention decodes the data according to the direction of the peak correlation and whether the peak occurred within the polarity window. The sync and polarity windows are then set to occur, such that the peak correlation of the next baud falls within the next instance of the sync window. In this way, data can be recovered continuously.
摘要:
An improved network for communication of message packets. The network of the present invention implements improved methods and apparatus for collision avoidance, idle channel detection and backoff estimation during communication on a media between a plurality of nodes (101-103, 114, 121, 122). The methods and apparatus include calculating a time period P after detecting the media is idle using a formula F where the formula F includes as a factor a pseudo-random delay factor T. If the media remains idle during the time period P, the device may transmit a message. The methods and apparatus further comprise ability to assign messages as being either priority or non-priority messages. Priority messages may be transmitted during priority message slots preassigned to transmitting nodes. Non-priority messages contend for the media during a period of time following the period set for transmission of priority messages.
摘要:
A method for automated topology discovery and management of meter nodes in a power grid is described. In the discovery mode any of the meter nodes is able to act as a proxy for a data concentrator to sort out the topology, and to determine the best path for communicating between a concentrator and each of the meter nodes.
摘要:
A method of determining a transaction identifier for a message to be sent from a node on a network (101). The node has an address table (430) and a memory. The method comprising the steps of: accessing the address table to determine an address for the message; and accessing the transaction identifier at a memory location corresponding to the address.
摘要:
In a system for encoding/decoding phase modulated data, each data word (520) includes 8 data bits, a parity bit, and ends with two coding bits. A transmitted BPSK signal is demodulated into a recovered signal that is decoded using a rotating reference frame that tracks the signal phase. The signal is compared against the reference frame and the signal phase characteristics are recorded for determining a bit position of a large phase shift most likely to cause a data inversion. A single bit error detected (2310) with the parity bit is corrected (2520) by inverting the bit having the smallest measured amplitude in the recovered signal of the data word. An inversion detected (2550) by the two coding bits is corrected (2720, 2725) by inverting each successive bit starting from the position with the large phase shift. Parity is rechecked (2730), and any single bit error is corrected (2735).
摘要:
A transceiver (25) for transmitting and receiving digital data represented as stair-stepped sinusoidal waveforms over twisted pair lines interconnecting nodes of a network. The transmitter (302) of the transceiver converts square waves into the stair-stepped sinusoidal waveforms by utilizing a number of current sources for supplying differing amounts of current to a resistor coupled across the twisted pair lines. Shift registers control a set of switches which control the direction and the amount of current flowing through the resistor. Thereby, the output voltage across the resistor can be controlled to produce signal to the shift registers. The receiver (303) of the transceiver re-convert received stair-stepped sinusoidal waveforms back to their respective digital signals.