Communications: electrical – Systems – Selsyn type
Reexamination Certificate
1999-10-08
2001-04-17
Pope, Daryl (Department: 2736)
Communications: electrical
Systems
Selsyn type
C340S315000, C340S315000, C340S315000
Reexamination Certificate
active
06218931
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to electronic communication and home automation, and more particularly, to devices for communicating on home-appliance networks.
2. Description of the Related Art
Home automation systems have gained increasing popularity due to advances in digital signal processing and reductions in the cost of home computer equipment. These systems allow centralized and remote control over electric and electronic appliances and devices in the home, such as interior lights, exterior lights, fans, and other devices. One system, by X10 Ltd., uses electrical sockets and electrical switches with transceivers that communicate over a house's electrical wiring system. The sockets and switches can receive commands from and/or provide status information to one or more control stations plugged into the house's wiring. The control system may be a specialized unit or a home computer configured to interface with the house wiring. With the appliances connected through this system, a user can readily execute simple controls over the appliances from a central location. These controls include turning on and off lights, dimming lights, setting lights and stereo equipment to turn on or off at predetermined or random times, and other similar functions.
The appliances in these systems communicate through high-frequency pulses (typically 120 kHz) transmitted on the home wiring grid during the zero-crossings of the 120 VAC/60 Hz voltage cycles. The presence or absence of a high-frequency pulse indicates a binary 1 or 0. The information is communicated with some redundancy: the two zero-crossings in each 60 Hz cycle are used to transmit one bit. If the high-frequency pulse is present during the first zero-crossing, it will be absent during the second, and vice-versa. In this version of the signaling system, the appliances can thus communicate at a rate of up to 60 bits per second.
With increasing complexity of appliances in the home, it is expected that more sophisticated signaling techniques will be necessary for transmitting information among the connected appliances. It may be useful, for example, to have increased data rates, enhanced noise immunity, simultaneous communication with more than one device, or the ability to communicate on a network other than the home wiring grid. Similarly, the prior art might require each device to have a complex input stack for monitoring all of the commands over the network instead of just the commands relevant to that particular device. Since implementing this stack would increase the software complexity, more hardware and computing power would also be required to support it. As a result, it might also be desirable to simplify these software and hardware requirements.
SUMMARY OF THE INVENTION
Described herein is a network interface for coupling residential appliance into a code-division multiple access (CDMA) network. The network is used to convey appliance control signals and an appliance status signals. The network interface includes a transmitter and/or a receiver, depending on the communications needs of the residential appliance.
The transmitter includes a digital-to-analog converter (DAC) that receives a stream of data and generates a baseband signal from the data stream. Also in the transmitter is a high-frequency oscillator that generates a carrier wave, and a high-frequency mixer that modulates the carrier with the baseband signal to generate a narrowband transmit signal. A spreading-code generator in the transmitter unit generates a spreading code that identifies the residential appliance. A spreading mixer modulates the narrowband transmit signal with the spreading code, thereby generating a wideband transmit signal. The wideband transmit signal is then coupled into the physical medium of the network. In one embodiment, the physical medium is a residential wiring grid, and a wiring interface in the transmitter unit couples the spreading mixer with the residential wiring.
A receiver in the network interface receives a wideband communications signal from the network. In one embodiment, the network medium is a residential wiring grid, and the receiver unit includes a wiring interface. The receiver wiring interface provides the wideband signal to a despreading mixer that recovers a narrowband signal using a locally-generated spreading code. A detector unit demodulates the narrowband signal to recover the received data.
The network interface may be incorporated in a wall socket or in a light switch. Alternatively, the network interface may be included in the residential appliance or inserted between the residential appliance and the residential electrical wiring.
Also decried herein is a transmitting network interface for a wired network. The network interface includes a modulator configured to receive a stream of transmit data and to generate a modulated carrier signal from the data. The modulated carrier is spread by a direct-sequence spreading circuit, using a node-specific spreading code, into a wideband signal. The wideband signal is then coupled onto the wired network.
Further, this disclosure describes a receiving network interface for a wired network. A receiver in the network interface receives a wideband signal from a network of residential appliances, and a direct-sequence despreading circuit uses a node-specific spreading code to recover a modulated carrier signal from the wideband signal. A detector then recovers a stream of received data from the modulated carrier signal.
REFERENCES:
patent: 5400246 (1995-03-01), Wilson et al.
Asghar Saf
Tobias David
Advanced Micro Devices , Inc.
Conley Rose & Tayon PC
Pope Daryl
LandOfFree
Home-appliance network with nodes identified by... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Home-appliance network with nodes identified by..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Home-appliance network with nodes identified by... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2509055