Transcript Modern Possibilities of Access and Transport Networks

Modern Possibilities of Access
and Transport Networks
Vladislav Skorpil
The principle of Time Division
Multiplex
The Principle of Pulse Code
Modulation (PCM)
The Principle of Delta Modulation
(DM) and Adaptivre delta
Modulation (ADM)
Adaptive Diferential PCM ADPCM
• For signal with no constant midle power,
samples are adapted to constant midle
power
The basic block diagram for TDM
system with digital modulation
• Older type
• Common codec
Transmiter part
Receiver part
The basic block diagram for TDM
system with digital modulation
• Modern type
• Individual codec
Quantizing step encoder
Weighting encoder (Bit encoder)
Counting Analogue to Digital
Convertor
Tracking A/D Convertor
Parallel A/D Convertor
Compenzating A/D Convertor
Shannon decoder
Shannon decoder response
Shannon Rack decoder
Shannon-Rack Decoder Response
Weighting Decoder (Bit Encoder)
Operational Amplifier
D/A Convertor with weighting
resistors
D/A Convertor with cross piece
structure of resistor networks
D/A Convertor with current sources
Compandors and non-linear
encoders
Compression and expansion
characteristics
A-low compression characteristic
Unipolar and Bipolar Signal, Signal
NRZ, RZ, TPC, SPC, HDB3,AMI
Code HDB3
• Maximal 3 zeroes in sequence
• When the sequence of 4 or more zeroes
exist, then forth one is encoded as the
impulse with the same polarity as the
previous one
• This bipolarity interruption must be positive
after negative and negative after possitive
(zero direct current part)
Isolation impulse
Identification of impulse
Decision eye – bipolar signal
Decision eye – unipolar signal, basic
noise
Influence of impulse interference
Influence of jitter
Generation of AMI signal
Quantizing distortion
Peak limiting
Time behaviour of sampling
Spectrum of sampling signal – PAM
1st sort
Ideal PAM 1st order (wide of
samples approaches to zero
Spestrum of sampling signal -2nd
order
Spectrum of PAM 2nd order – wide
of samples equals to sampling
periode
• This is the end of my slides to the theme
Modern possibilities of access and transport
networks
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