Patent Application
20080143492
The embodiments described herein relate to a power line communication (PLC) system.
Electrical systems typically include a switch being coupled to an electronic device, wherein the electronic device may be actuated or energized. As commonly known, the switch enables or inhibits the flow of electric current to the device so as to cause or disable device actuation. In the context of conventional vehicular electrical systems, coupling of electrical system components occurs through the use of electrical wires. However, the required wiring infrastructure that enables communications with the electronic devices is a concern as vehicle packaging space is limited.
The embodiments described herein were conceived in view of these and other disadvantages of conventional communications systems.
The embodiments described herein include a communication system and method configured to communicate over a power line. The system includes a transmitting device configured to generate a carrier signal having a predetermined frequency over the power line. A receiving device is also included wherein it filters signals not having the predetermined frequency and receives the carrier signal. Accordingly, the receiving device activates an electrical device in response to the carrier signal.
The novel features of the described embodiments are set forth with particularity in the appended claims. These embodiments, both as to their organization and manner of operation, together with further advantages thereof, may be best understood with reference to the following description, taken in connection with the accompanying drawings in which:
As required, detailed descriptions of embodiments are disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale, and some features may be exaggerated or minimized to show details of particular components. Therefore, specific functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art.
The embodiments described herein include a power communication line (PLC) system that enables communication between electrical components and/or devices over a direct current (DC) power line. The PLC system described herein may be installed during assembly of a system having a DC power line or retrofitted to virtually any power line to enable communications, actuation, energization, and/or activation of electrical devices.
Regarding vehicle 10, it includes a power line 11 that enables the transmission of signals from a transmitting device 12 to a receiving device 14. As described above, power line 11 may be a DC power line. Transmitting device 12 may include a switch being coupled to transmitter circuit. For example, transmitting device 12 may include a lamp switch being coupled to a transmitter circuit for energizing or de-energizing lamps on vehicle 10. Transmitting device 12 may be a transmitter circuit that generates control signals for other vehicular devices and systems in response to inputs from a switch, controller and the like.
Receiving device 14 may include a receiving circuit that is coupled to an electronic device. As shown in
Transmitting device 12 and receiving device 14 are configured to automatically select various communication frequencies to enable optimal and efficient transmission of control signals and the like. In one aspect, multiple transmitting devices and receiving devices may communicate over power line 11. As such, each pair of transmitting and receiving devices may utilize different transmitting frequencies so as to minimize signal congestion and interference.
The signals transmitted by transmitting device 12 include sinusoidal signals having a desired or predetermined frequency. These sinusoidal signals may be referred to as carrier signals. Receiving device 14 is configured to filter signals not having the predetermined frequency and receive the carrier signal. It is recognized that in some embodiments, transmitting device 12 and receiving device 14 may be implemented as a unitary device or transceiver.
In some cases, multiple transmitting devices may utilize a single power line. Accordingly, based on whether a desired frequency has previously been used by other devices on a specific power line, transmitting device 12 is configured to select alternative frequencies by which the carrier signal is generated. In one embodiment, the determination of whether a particular frequency has been used occurs by analyzing a checksum of the carrier signals transmitted from transmitting device 12 to receiving device 14. Ideally, the checksum of the carrier signal when transmitted by transmitting device 12 should be the same when received by the intended receiving device 14. If the checksum is not the same, this discrepancy is an indication that multiple carrier signals or other signals are being transmitted on a single power line.
In one embodiment, a controller is coupled to devices 12 or 14 for verifying the carrier signal checksum. In the event that the checksum is not verified (i.e., the checksum as transmitted by transmitting device 12 differs from the checksum as received by receiving device 14), the controller may generate a signal causing transmitting device 12 to transmit the carrier signal at an alternative frequency. As such, the controller would generate a signal for receiving device 14 causing it to tune to/receive signals having the alternative frequency while disregarding signals not having the alternative frequency. It is recognized that although the checksum may be used as described above, virtually any type of signal identifier may be used to meet specific design criteria. In some embodiments, filtering of signals and tuning to a desired frequency may occur through the use of a resistor and capacitor network and/or a phase-locked-loop (PLL) device.
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Controller 48 also generates a control signal for amplifier 52. As stated above, PLL 50 enables the selection of a predetermined frequency for the carrier signal that is generated by amplifier 52. In response to the control signal from controller 48, amplifier 52 generates the carrier signal as received by a filter and resistive network 54. A mixer 56 mixes signals from filter and resistive network 54 and PLL 50. Amplifier 58 then receives and amplifies the mixed signal from mixer 56. The carrier signal is then transmitted to a receiving device via power line 11.
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A band pass filter 82 filters the signal received from a transmitting device. Mixer 84 mixes the signal filtered by filter 82 and the signal from VCO 78d. An amplifier 86, which may be an intermediate frequency (IF) amplifier, amplifies the signal from mixer 84. A band pass filter 88 then filters the amplified signal from amplifier 86. An AM detector 90 receives and modulates the filtered signal, which is then received at a device 91.
While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.
