AUTOMOTIVE GAUGE SYSTEM USING A POWER LINE CARRIER

• US 20060187021A1
• Filed: 02/22/2005
• Published: 08/24/2006
• Est. Priority Date: 02/22/2005
• Status: Active Grant

• Current Assignee: Canadian Automotive Instruments, Ltd.
• Original Assignee: Instrument Systems Inc.
• Inventors: Stevenson, W. Timothy
• Granted Patent: US 7,352,281 B2
• Time in Patent Office: Days
• US Class Current: 340/538.110
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00

Abstract

A data display system including a plurality of data sources; a data transmitter coupled to the data sources and to a transmission network comprising a power line; wherein the data transmitter comprises means for modulating the data as a frequency modulated carrier and means for transmitting the carrier over the power line; and a plurality of gauges each having a display and coupled to the power line, and a data receiver comprising means for demodulating the carrier and means for translating the data to the display. The gauges are coupled to the data transmitter only by the power line, disregarding any ground connections, and the power line provides power to the gauges and the data transmitter.

Claims

1. A data display system comprising:

(a) at least one data source;

(b) a data transmitter coupled to the at least one data source and to a transmission network comprising a power line;

wherein the data transmitter comprises means for modulating the data as a frequency modulated carrier and means for transmitting the carrier over the power line;

(c) at least one gauge having a display and coupled to the power line, and a data receiver comprising means for demodulating the carrier and means for translating the data to the display;

(d) wherein the at least one gauge is coupled to the data transmitter only by the power line, disregarding any ground connections, and wherein the power line provides power to both the at least one gauge and the data transmitter.

2. The system of claim 1 comprising a plurality of data sources, a single data transmitter and a plurality of gauges, wherein each data source has a corresponding gauge, and the transmitter outputs a carrier combining the data sources.

3. The system of claim 2 wherein each of the gauge displays comprises a human readable analog display.

4. The system of claim 1 wherein the modulation means outputs a square wave having a frequency of at least about 50 KHz.

5. The system of claim 4 wherein the modulation means outputs a square wave having a frequency of at least about 75 KHz.

6. The system of claim 5 wherein the modulation means outputs a square wave having a frequency between about 100 KHz and 500 KHz.

7. The system of claim 4 further comprising means for removing higher harmonics of the square wave output prior to signal amplification.

8. The system of claim 4 wherein the carrier transmission means comprises an amplifier and a capacitative coupler or a transformer coupler.

9. The system of claim 1 wherein the gauge comprises a frequency demodulator, a data detector and microcontroller for translating the data to drive the gauge display.

10. The system of claim 1 wherein one or both of the transmitter and the gauge comprises a transient voltage protection device.

13. The method of claim 10 wherein the square wave is converted to a sine wave and amplified prior to transmission over the power line.

11. A method of connecting a gauge panel comprising a plurality of gauges to a plurality of data sources with a transmission network consisting of a power line, the method comprising the steps of:

(a) providing power to each gauge and a data transmitter with the power line;

(b) modulating the data received from the data sources as a frequency modulated carrier and transmitting the carrier over the power line; and

(c) demodulating the carrier in the corresponding gauge, selecting data relevant to the corresponding gauge and displaying the relevant data as a human readable display.

12. The method of claim 11 wherein the data is first converted to an asynchronous serial data stream, and is then modulated to a frequency modulated square wave.

15. The method of claim 11 wherein the carrier has a frequency greater than about 50 KHz.

16. The method of claim 15 wherein the carrier has a frequency greater than about 75 KHz.

17. The method of claim 16 wherein the carrier has a frequency between about 100 KHz and about 500 KHz.

14. The method of claim 111 wherein the data is extracted from the carrier by a phase lock loop filter and a data detector comprising a voltage comparator.