Echelon Corporation

J Marcus Stewart

Philip H Sutterlin

Amy O Hurlbut

Walter J Downey

Benjamin W Chui

Milton T Tormey

Glen Meyers Riley

Robert A Dolin

Karl F Osterlund

Marie E Andrus

A receiver for detecting spread spectrum binary data particularly on a power line in the presence of channel distortion. In one embodiment a standard pattern ideally suited for minimal distortion in the channel is used in conjunction with an alternate pattern which is developed to better detect carrier and data in the presence of certain channel distortion. The receiver switches between the standard and alternate pattern to provide improved detection. In another embodiment an adaptive pattern is used which is developed from the receive signal. For instance, the signal over several bit times is averaged to provide a pattern which is correlated with a receive signal.

Adaptive reference pattern for spread spectrum detection claims

Adaptive reference pattern for spread spectrum detection

A power line communications analyzer (PLCA) provides a signal strength metering system and selectable signal attenuation functions 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. 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.

Power line communications analyzer

A power supply for a node that transmits data onto a power line. A DC supply and capacitor supply power to the node where the output current of the DC supply may be less than required for transmission by the node. When the voltage on the capacitor drops to Vmin transmissions are stopped allowing the capacitor to recharge. A timing circuit is used to determine when to begin transmission to compensate for variables in the node such as line voltages and part tolerances.

Capacitor power supply for intermittent transmission

A power supply for operating from a switched leg of an AC power line and for powering a transmitter is described. A switch provides current during the beginning of each AC half cycle to an inductor and charges a capacitor. When the switch is open, the inductor continues to charge the capacitor. During the time that the inductor is coupled to that AC line, the switched leg is open. For instance, the signal used to close the switch also prevents a triac in the switched leg from conducting. When the voltage on the capacitor drops to a predetermined level transmission from the transmitter is inhibited. A timing circuit is used to determine when to begin transmissions to compensate for variables in the node such as line voltages and part tolerances.

Apparatus for powering a transmitter from a switched leg

A method and apparatus for compensating for distortion in a spread spectrum communications system particularly useful where the spread spectrum is transmitted over a power line. The information carrying signal (ICS) is split into two sub-bands and the ICS in one sub-band (or a correlation value determined from the ICS in that sub-band) is delayed relative to the other sub-band. The ICS (or correlation values) from the two sub-bands are recombined after the delay and processed in an ordinary manner. The time delay is selected so as to compensate for the distortion. In one embodiment, the correlation peaks in each of the sub-bands are examined and the time delay is determined by, in effect, aligning the peaks in the two sub-bands in time so that when the two sub-bands are combined, a sharper correlation peak is obtained.

Split band processing for spread spectrum communications

In a communications system, an apparatus and method for detecting a valid signal from noise. An adaptive threshold is used to qualify a received signal. The adaptive threshold is set according to the number of false detects occurring within a given time interval. The number of false detects is initially determined by a quick qualification process. This initial number is subsequently adjusted by a more accurate qualification process. The transmitted signal is modulated with a particular pattern. Upon receiving the signal, it is demodulated to retrieve that pattern. The demodulated pattern is correlated against multiple reference patterns and combined to provide a measure of peak correlation that is independent of pattern phase. Furthermore, a tone detector is used to distinguish valid signals from interfering tones. Two different types of detection methods are performed in parallel. One is based on the energy of the received signal, whereas the other is based on the correlation of the received signal.

Apparatus and method for detecting a signal in a communications system

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 is compared with the instantaneous signal level to develop a blanking circuit control signal. Additionally, snubbing occurs in the circuit which determines the average signal level to prevent noise from building-up the average signal level. A hold-off signal is used in this circuit to prevent the average signal level from being latched permanently low. A unique infinite impulse filter subtracts out the D.C. offset thereby improving the dynamic range of the blanking. Additionally, the average signal level is used by AGC logic to control the gain at the front end of the apparatus. The state and switching of the AGC is controlled to minimize errors.

Apparatus and method for reducing errors in data caused by noise through

The present invention works in combination with an integrated set of hardware and software tools that support rapid design, programming, debugging, implementation, and testing of local operation network local operation network nodes and applications. These hardware and software tools speed development by enabling developers to use object-oriented concepts, such as network variables and input/output objects, rather than low-level constructs. The development environment operates with an IBM PC/AT or compatible computer and can grow from a single emulated application node to a completely distributed system of up to 24 emulated nodes and hundreds of remote nodes. The invention is mainly directed to a repeater circuit which is part of a control processor board, and is used to send and receive the serial signals between the PC and connected development stations, and the serial data protocol which enables the development stations to be automatically configured at system start-up. The automatic configuration capability avoids the necessity of manually configuring aerial devices on a network so that each has a unique address.

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San Jose, CA, United States of America

J Marcus Stewart