Power Line Power Line Communication using an Communication using an Audio InputAudio InputHashem AL-khateebAbdullah ShabAhmed rbaba’hTariq Ziad

OutlineOutline

Introduction to general PLC

A Detailed Look

Proposed Design

Project Build and Tests

Advantages & Disadvantages

Application

Conclusions

Introduction to general Introduction to general PLCPLC

Power line communication or power line carrier (PLC), also known as Power line Digital Subscriber Line

(PDSL), mains communication, power line telecom (PLT), or power line networking (PLN), is the use of

existing electrical cables to transport data, and it has been around for a very long time. Broadband over

Power Lines (BPL) uses PLC by sending and receiving information bearing signals over power lines to provide

access to the internet.

A Detailed Look…A Detailed Look…

MODULATION

DEMODULATION

•Interference from AC lines which operate at 50 Hz - 220 V.

•FM modulation necessary to transmit at higher frequencies.

•Demodulation circuit required to demodulate the modulated signal and convert to standard audio output.

Filter circuits required to block 50Hz noise and any frequencies not part of the transmitted audio.

Design OverviewDesign Overview

Transmitter

Reciever

Low Pass Filter Power Supply

High Pass Filter AmplifierFrequencyModulated

Demodulator

Audio

Out

Audio

In

Power SupplyLow Pass Filter

AmplifierHigh Pass FilterFrequencyModulatedOscillator

PowerLines

Modulation CircuitModulation Circuit

Modulation Circuit Modulation Circuit Continued…Continued… The VCO used for modulation purposes

was the LM565. The frequency production of the VCO

was controlled using:

where Rt = Timing Resistance on pin 8. Ct = Timing Capacitance on 9. Vcc = Power Supply Voltage. Vc = The control voltage on Pin 7.

2.4( )f Vcc Vc

RtCtVcc

Demodulation CircuitDemodulation Circuit

Demodulation Circuit Demodulation Circuit Continued..Continued.. LM565 used to implement the VCO. The input signal coupled in to the circuit

through pin 2. A more complicated network of components at

output for noise reduction purposes. Potentiometer used to match current

frequency to the carrier frequency.

FiltersFilters

Noise above 10Khz was minimal Standard HPF implemented.

1

2f

RC Chosen values were R = 15kΩ and

C = 1nF

Component SelectionComponent Selection

LM 565- Readily available.- Carrier frequency

adjustment through timing capacitor and resistor.

Potentiometers– Easy tuning manipulation

Design and TestingDesign and Testing

1) Build Modulator/Demodulator.2) Test Modulator/Demodulator Functionality.3) Build Filters.4) Test Filter Functionality.5) Combine Modulator/Demodulator with Filter.6) Test Transmitter/Receiver Functionality.7) Combine Transmitter/Receiver with 50 Hz

Simulated Noise.8) Test with Simulated Noise.9) Combine Transmitter/Receiver with 50 Hz

Power Line.10) Test with Power Line (Variac).

Board LayoutBoard Layout

Board Layout - Board Layout - TransmitterTransmitter

Modulator

Computer Audio Signal

100 kHz FM Modulated

Signal

Modulator TestingModulator Testing

Timing Capacitor (pin 9):~100 kHz

Modulator output :

BoardBoard Layout-coupling stage Layout-coupling stage

Board Layout-receiverBoard Layout-receiver

Demodulator

DC Power

(No signal)

Demodulator TestingDemodulator Testing

Timing Capacitor (pin 9):

Filter

Input Signal50 Hz

100kHz Output Signal

Filter TestingFilter Testing

50 Hz Response:

Gain = .01 V/V

100 kHz Response:

Gain = .98 V/V

Modulator Power Strip Demodulator

Computer

Speaker

(Filter) (Filter)

Integration TestingIntegration Testing

Qualitative Evaluation-Clarity of signal (after tuning)

Quantitative Evaluation- SNR (at 10 kHz)- 29.06 dB

Modulator Power Strip Demodulator

Computer

SpeakerSimulator

50 Hz, 20 volts

Communication with Communication with simulated 50Hzsimulated 50Hz

Qualitative Evaluation-Clarity of signal (after addition tuning)

Quantitative Evaluation- SNR (at 10 kHz)- 17.19 dB

Modulator Power Strip Demodulator

Computer

SpeakerPower Line

50 Hz, 220 volts

Communication over Communication over Power LinePower Line

Challenges - Filter Challenges - Filter PerformancePerformance Relative background noise persistent through

the initial filter design. – DC offset distortion of the output signal

• DC offset connected to ground through inductors causing over current conditions.

Proposed three stage RC filter design

Filter PerformanceFilter Performance

CC2C=1.0 nF

CC1C=1.0 nF

RR1R=15 kOhm

TermTerm2

Z=1000 OhmNum=2

TermTerm1

Z=1000 OhmNum=1

RR2R=15 kOhm

RR3R=15 kOhm

CC3C=1.0 nF

20 40 60 80 1000 120

-250

-200

-150

-100

-50

-300

0

freq, KHz

dB(S

(2,1

))

Advantages of PLC Advantages of PLC

Low cost. Low power consumption. data over PLs was used for protection. Data rates above 1Mbps.

Disadantages of PLCDisadantages of PLC

Ground Issues. Radiation of the Transmitted Signal. Impedance Mismatches. The Time-variant.

Application OF PLCApplication OF PLC

VoIP (Voice over IP). VoD (Video On Demand). Online Gaming . AMR (Automatic Meter Reading) . Smart Home Management . Power Grid Management and Control . Local Area Network (LAN). Wide Area Network (WAN) CCTV and Security Networks

This telecommunications model has multiple advantages over others including speed, an established local loop, and dedicated connections. These advantages make Power Line technology an attractive alternative for telecommunications systems.

Power line communication uses the existing power lines within a home, building or an outdoor power distribution network to transmit data from one device to another. With a well-designed power line solution, devices should be able to communicate using the existing wiring infrastructure, without any rewiring or modification. This makes power line communication one of the most cost-effective means for networking devices.

ConclusionsConclusions

QUESTIONS?