Power line carrier data transmission systems having signal conditioning for the carrier data signal

• US 5,870,016 A
• Filed: 02/03/1997
• Issued: 02/09/1999
• Est. Priority Date: 02/03/1997
• Status: Expired due to Fees

• Current Assignee: Eua Day Div. Of Eua Cogenex Inc.
• Original Assignee: EVA Cogenics Incorporated Euaday Division
• Inventors: Shrestha, Bickram
• Primary Examiner(s): Mullen, Jr., Thomas J.
• Assistant Examiner(s): Pope, Daryl C.
• Application Number:
  US08/794,662
• Time in Patent Office: 736 Days
• Field of Search: 340/310.01-310.07, 340/310.08, 340/870.18, 340/870.39, 375/220, 375/254, 375/296, 375/297
• US Class Current: 375/222
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• CPC Class Codes: H04B 2203/5466 using three phases conductors
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines

Abstract

Data bit error rates for power line carrier data transmission, in commercial and industrial applications, such as in office buildings and manufacturing plants is improved by connecting the power line transceiver modem to the power line via a booster amplifier and filter circuit which raises the carrier data signal level of the order of 20 dB, thereby overcoming spikes and other noise which can adversely affect the error rate. The power for the carrier data transmission system is obtained from the power lines over which the data is transmitted through filters which isolate the power supply from the power line thereby reducing the introduction of power supply noise into the power line and further improving the data bit error rate.

Claims

1. In a power line carrier data transmission system having carrier transmission means for generating and receiving a modulated carrier via power lines, the improvement comprising means between the transmission means and the power lines for boosting the level of the modulated carrier signal sufficient to overcome noise appearing on the power lines, and means for coupling the output of said boosting means to the power lines which presents a high impedance at the carrier frequency, said coupling means further comprising a three phase coupling circuit connected between the power lines and a filter tuned to the frequency of said carrier.

2. The invention in accordance with claim 1 where said boosting means is an amplifier having an input coupled to receive modulated carrier signals from the carrier transmission means and including level setting means for providing an output level increase of the order of 20 dB of the modulated carrier signal.

3. The invention in accordance with claim 2 further comprising means for detecting when the transmitting and receiving means is generating a carrier, and means for placing the amplifier in an inactive state when the transmitting means is not generating the carrier.

4. The invention in accordance with claim 1 further comprising an inverter regulated power supply connected to said power lines via a blocking filter tuned to the frequency of said carrier.

5. The invention in accordance with claim 4 further comprising a common mode filter connected across said power lines to cancel noise which appear across said power lines before said noise reaches said inverter power supply.

8. The invention in accordance with claim 5 further comprising means connected across to receive input of the modem across the series leg and the shunt leg of the filter for preventing voltages above certain peak to peak voltages of the carrier signal from being presented across the received signal input of the modem.

6. In a power line carrier data transmission system having carrier transmission means for generating and receiving a modulated carrier via power lines, the improvement comprising means for boosting the level of the modulated carrier signal sufficient to overcome noise appearing on the power lines, means for coupling the output of said boosting means to the power lines which presents a high impedance at the carrier frequency, said boosting means being an amplifier having an input coupled to receive modulated carrier signals from the carrier transmission means and including level setting means for providing and output level increase of the order of 20 db of the modulated carrier signal, and wherein said amplifier is an operational amplifier and further comprising means connected across the output of the operational amplifier for preventing the output of the operational amplifier from increasing to voltage levels exceeding levels which can damage the operational amplifier.

7. In a power line carrier data transmission system having carrier transmission means for generating and receiving a modulated carrier via power lines, the improvement comprising means for boosting the level of the modulated carrier signal sufficient to overcome noise appearing on the power lines, means for coupling the output of said boosting means to the power lines which presents a high impedance at the carrier frequency, and wherein said coupling means provides, isolating means for isolating said power lines from said generating and receiving means, said isolating means is a band pass filter which has a series leg and a shunt leg, said series leg providing a connection to a received signal input of a modem which provides said transmission means, and said filter being tuned to the carrier frequency of the signal generated by the modem.