Lect-21_07 - 5 Why Digital? (contd.) Image stored in...

Info iconThis preview shows pages 1–18. Sign up to view the full content.

View Full Document Right Arrow Icon
1 The Noise objective was 3pW/km. The total noise power measured at the end of 6400 km was 8000 pW, which is less than 3pW/km. The (S/ N) O was 40 dB. 2 coaxial ’tubes’ required for 10,800 channels, one for ‘Go’ and the other for ‘Return’. For L5 - 22 ‘tubes’ are there with 2 spare ‘tubes’. Total Capacity – 1,08,000 VF Channels. (Operational since 1974)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Lecture - 21 Noise Figure, Noise Temperature 24-02-2007
Background image of page 2
3
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Why Digital? Regeneration – digital coding of signals involves two states and shape of the pulse is not important as long as energy is the same. Digital Signals are more immune to noise In analog Communication noise is cumulative. Distortion cannot be corrected. Digital circuits are more reliable Digital hardware allows more flexible implementation Time Division Multiplexing (TDM) is simpler than FDM. Different types of signals can be treated as identical signals. Digital techniques lend themselves naturally to signal processing functions – coding, encryption etc.
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 10
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 12
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 14
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 16
Background image of page 17

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 18
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 5 Why Digital? (contd.) Image stored in digital form can be reproduced without deterioration Disadvantages: They require more bandwidth. Efficient compression techniques are coming up at the cost of increased complexity of implementation. They tend to get more signal processing intensive. Synchronization is a problem Bit Synch, clock synch, frame synch. etc. More bandwidth may be required. Degradation in S/N is not graceful. 6 7 8 Formatting of Information Signals 9 Sampling Instantaneous Sampling Natural Sampling Flat Top Sampling 10 Instantaneous Sampling 11 Flat Top Sampling 12 Distortion due to finite width of Pulse during Sampling Aperture Effect in Flat Top Sampling 13 14 PCM Generation 15 Quantization Uniform and non-uniform 16 A- law and - law Characteristics 17 - law Characteristics m = x/x max ; v = y/y max 18 A- law and - law Characteristics...
View Full Document

This note was uploaded on 09/24/2010 for the course MATHEMATIC AAOC C222 taught by Professor Prof.dilipkumarsatpathi during the Fall '07 term at Birla Institute of Technology & Science, Pilani - Hyderabad.

Page1 / 18

Lect-21_07 - 5 Why Digital? (contd.) Image stored in...

This preview shows document pages 1 - 18. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online