IT 327 - Schweber Chap 11 1

Thought of the Day

With thoughtless and impatient hands, we tangle the plans the Lord hath laid. Then when we cry in pain, He answers, “Be patient, my son, and wait while I untangle the knot.”

Elder Boyd K. Packer

IT 327 - Schweber Chap 11 2

Schweber, Chap 11:Digital Communication

Fundamentals

Chap 11: Complete Digital Communication System

IT 327 - Schweber Chap 11 3

Shift Register (AKA: SERDES)

IT 327 - Schweber Chap 11 4

Chap 11: Layers of Communication

IT 327 - Schweber Chap 11 5

Companding

IT 327 - Schweber Chap 11 6

Bit-Level Synchronization

IT 327 - Schweber Chap 11 7

Synchronizing: Options

IT 327 - Schweber Chap 11 8

1. Send the clock as a separate signalA. Requires separate channel, more BWB. Common for short-distance communication, where each channel is nearly free

2. Reference a common signalA. 50 Hz, 60 HzB. GPS clock

3. Derive clock timing from the received data4. Use special bits as part of the data stream

#3, 4 together by far the most common for distances over about 15 feet.

Synchronizing: PLLs

IT 327 - Schweber Chap 11 9

Synchronizing: PLL Capture & Lock

IT 327 - Schweber Chap 11 10

Synchronizing: PLL Special

Bits

IT 327 - Schweber Chap 11 11