Modulation & Multiplexing - week 7
- Created by: harveyf2801
- Created on: 13-01-21 16:30
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- Modulation
- Pulse position modulation (PPM)
- Larger amplitudes create wider gaps from reference pulse
- High bandwidth to transmit and store which creates more errors
- Larger amplitudes create wider gaps from reference pulse
- Pulse width modulation (PWM)
- Larger amplitudes create wider pulses
- High bandwidth to transmit and store which creates more errors
- Larger amplitudes create wider pulses
- Pulse number modulation (PNM)
- Larger amplitudes creates more pulses
- Larger amplitudes creates more pulses
- Pulse code modulation (PCM)
- Samples audio, quantizes these and codes it as a binary number in pulses
- Encoder and decoder clock needs to be exactly synchronized
- Can be fixed by ...
- Encoding a separate clock signal
- Adding a signal to reset clocks regularly
- Using bit stuffing to break up long runs of 1's or 0's
- Can be fixed by ...
- Pulse amplitude modulation (PAM)
- Larger amplitudes create higher pulse amplitudes
- Larger amplitudes create higher pulse amplitudes
- A method of encoding information for transmission
- Channel coding
- Return to zero (RZ)
- Pulse for 1 and no pulse for 0 (pulse starts at period and ends half way)
- Non return to zero (NRZ)
- Pulse for 1 and no pulse for 0 (pulse starts and ends at period start and end)
- Does not independently facilitate clock synchronization
- Non return to zero inverted (NRZI)
- Pulse changes state for 1 (pulse starts and ends half way through period)
- Immune to polarity reversal
- Binary frequency modulation (digital FM)
- Pulse changes state twice for 1 and once for 0 (pulse starts at period and ends half way for 1 and at end of period for 0)
- Fully self clock
- Phase modulation (PE) / Manchester coding
- Pulse for 1 (low-high), pulse for 0 (high-low)
- Phase modulation (PE) / Manchester coding
- Binary frequency modulation (digital FM)
- Partially self clock
- Return to zero (RZ)
- Pulse for 1 and no pulse for 0 (pulse starts at period and ends half way)
- Return to zero (RZ)
- Binary frequency modulation (digital FM)
- Pulse changes state twice for 1 and once for 0 (pulse starts at period and ends half way for 1 and at end of period for 0)
- Fully self clock
- Phase modulation (PE) / Manchester coding
- Pulse for 1 (low-high), pulse for 0 (high-low)
- Phase modulation (PE) / Manchester coding
- Return to zero (RZ)
- Pulse position modulation (PPM)
- De-multiplexer
- Used in DAC to separate a single line into separate channels
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