Synchronization/reference pulse-based powerline pulse position modulated communication system

Abstract

A transmitting controller is connected to a powerline and on command places a reference signal and a series of signal pulses in the powerline at a series of signal timing positions related to zero voltage crossing points so that the signals pulses are substantially in the powerline temporal quiet zone. The receiving controller is connected to the powerline and has a filter circuit therein which filters away the powerline AC signal and noise to leave the reference and signal pulses. The signal pulses are compared to the position of starting reference pulses to determine in which signal timing position the pulses have occurred. Digital data is communicated over the powerline in accordance with the nature placement of the data pulses related to the reference pulse positions. The timing zone for transmission and signals is preferably about 500 to about 1000 microseconds away from zero voltage crossing.

Description

CROSS-REFERENCE[0001]This invention is a continuation-in-part of my prior application Ser. No. 09 / 656,160 entitled “POWERLINE PULSE POSITION MODULATED COMMUNICATION APPARATUS AND METHOD”, filed Sep. 6, 2000.FIELD OF THE INVENTION[0002]This invention is directed to an apparatus which enables digital communication between two or more devices wherein the devices are connected to the same powerline and use the same powerline to receive power and as a physical channel for electronic intercommunication.BACKGROUND OF THE INVENTION[0003]There are devices which are more conveniently used if they can be remotely controlled. In a household, such devices are mostly appliances and lighting loads. The appliances and lighting loads may be remotely controlled for a number of different reasons. For example, for night security, some lights may be controlled by a timer. In other cases, different lighting intensity and different lighting distribution may be desirable in a single room, depending upon it...

AI Technical Summary

Benefits of technology

[0008]In order to aid in the understanding of this invention, it can be stated in essentially summary form that it is directed a powerline pulse position modulated communication apparatus and method. The transmitting portion of the apparatus senses the zero voltage crossing point in the powerline and transmits a series of signal pulses at a set of specified positions, the position of the data pulse relative to the starting reference pulses representing digital data in the form of a digital number. The set of all possible relative positions is in the quiet zone adjacent, but spaced from the main voltage zero crossing point. The receiving circuit also senses the voltage zero crossing point and can reliably detect the signal pulse in the background powerline noise because of the knowledge of where the signal pulse is expected in the quiet zone adjacent, but away from the zero crossing point and because of the high magnitude of the very robust signal pulse even after significant residential attenuation. After determining in which one of the possible relative positions the signal pulse was located, the associated digital data in the form of a digital number is easily determined. Thus digital data is communicated from one device through the powerline to another device using this method of powerline pulse position modulation.

[0009]It is a purpose and advantage of this invention to provide a method and apparatus for reliable communication of digital data over the powerline by means of a powerline pulse position modulation communication method.

Problems solved by technology

Normally, people do not make such changes because it is inconvenient to do so.

The problem is the connection between the controller and the lighting load.

Such connection may be hard-wired, but such is complex and very expensive to retrofit into an existing home.

Another connection system may operate at radio frequency, but this has proven difficult to implement because the FCC requires low signal levels which are subject to interference and because the transmission and receiving circuitry is complex and expensive.

Prior powerline communication schemes have had difficulties employing the powerline as a communication channel because the communication signals after being attenuated by the powerline circuitry are very small compared to the background noise.

It is impossible to avoid the fact that between certain locations in a residence there will be very high attenuation of any transmitted signals.

It has been difficult to reliably separate the highly attenuated communication signals from the background noise on the powerline.

The situation is further aggravated and complicated by the fact that the noise and attenuation parameters are constantly and unpredictably changing as loads are connected and disconnected both inside the primary residence and inside any of the many neighboring residences attached to the same mains power transformer.

There is no practical way to avoid the complications caused by this fact.

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