Elec 5 AQA
Some of the Key Points of the Elec 5 AQA Specification
- Created by: Joey
- Created on: 26-05-13 15:11
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- Elec 5 AQA
- Transmission Media
- Twisted Pair
- Coaxial Cable
- Fibre Optics
- Total Internal Reflection
- Laser Diode to Transmit
- Photodiode to Receive
- Output pulse isn't sharp
- Need to know how to draw cross section of each
- Multiplexing
- Allows more information to pass over a medium
- FDM - Frequency Division
- Seperate Carrier Frequency for each signal
- Analogue and Digital
- TDM - Time Division
- Digital only
- Seperate time slot for each signal
- Several Signals being sent one after the other in time
- Signal Degradation
- Attentuation
- Radiation
- Crosstalk
- Interference from adjacent cables
- Untitled
- Distortion
- Signals Produced and added to a signal as it travels
- Noise
- Random signals added to a signal as it travels
- Dispersion
- Different Frequencies travel at different speeds
- Attentuation
- Tuned Circuit
- Resonance when XL = XC
- Simple Receiver
- Poor Selectivity
- Poor Sensitivty
- As there is no amplification
- Superhet Receiver
- Aerial
- Mixer
- If Amplifier
- Demodulator
- AF Amplifier
- Loudspeaker
- Non-Inverting Op Amp
- AF Amplifier
- Demodulator
- If Amplifier
- Mixer
- Aerial
- Modulation
- PWM - Pulse Width Modulation
- PAM - Pulse Amplitude Modulation
- PPM - Pulse Position Modulation
- PCM - Pulse Code Modulation
- Serial Transmission
- Serial Vs Parallel
- Half Duplex - Only one medium needed
- Start bit , Stop bits, Parity bit
- Shift Register with D type Flip-Flops
- Multiplexer
- Need to know how to draw with AND gates
- Low Pass Filter
- Input Resistor on inverting input
- Capacitor and Resistor on feedback
- Packet Switching
- Checksum is to check whether data is corrupt
- Destination Address is to specify where data is to be sent
- Items that could be in packet header
- Checksum
- Destination Address
- Source of Address
- Length of Data
- Protocol used
- Has Improved security compared to other links
- Transmission Media
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