Exam #2 Study Guide
Fall 1999 (Sec. B, Russell)
DATE AND TIME: Thursday, October
21, 1999 during the usual class time.
SUBJECT MATTER: The exam will cover the lecture
topics and homework assignments for Chapter 2, Sections 2.1 through Sections
2.5 inclusive.
General Information
- Exams are closed book. One 81/2 by 11 sheet
of paper can be used for reference to study notes. No other information
is allowed.
- Palm computers and calculators will not be
used unless specifically instructed to do so on the exam.
- The textbook problems that apply to the exam
are: 2-1, 2-2, 2-3, 2-4, 2-7, 2-13, 2-17, 2-18, 2-23, 2-41.
- Selection of exam problems will give emphasis
to the topics emphasized in the lectures and the problems assigned as homework.
- Re-read Chapter 2 through Section 2.5
- Shannon-Hartley Channel Capacity Theorem and
Nyquist Sampling Theorem will be covered again.
Example Study Topics
BITS-BITS-BAUD!!
Channel capacity "rule of thumb"
More Shannon's Law
Channel Information Rate, R
The Decibel
"Sampling" (A to D conversion)
Frequency, Bandwidth, Wavelength
More Shannon's Law
Data Rate, Information Rate, Baud Rate, etc.
Frequency, Bandwidth, Wavelength
Transmission Media
Radio Transmission
- Channel Bandwisth
- "Carrier"
- Modulation
- Amplitude only
- Phase only
- Quadrature Amplitude Modulation (QAM)
- QAM constellations
Attenuation, Dispersion, Multipath and Fading
Lightwave Transmission
Attenuation, Dispersion, Multipath and Fading
Baseband Transmission (no "carrier")
Modulation
- On-Off Keying or Pulse Code Modulation (PCM)
- Pulse Amplitude Modulation (PAM)
"RS-232" and the "UART"
Telephone System
- QAM
- FDM
- WDM
- TDM
- T1 'Carrier'
- SONET
Narrowband ISDN
Example Exam Questions
1. A physical layer
channel has a Shannon channel capacity limit of 20 kbps and a physical
channel bandwidth of 5.0 kHz. What signal-to-noise ratio is required to
meet this theoretical limit?
2. A 12-bit analog-to-digital
converter is used to digitize an analog source. The source information
bandwidth is 5 kHz. What is the minimum bit rate needed to send this digital
information over a noisless channel?
3. How much bandwidth
(in Hz) is ther in 0.1 micron of sprectrum at a wavelength of 1 micron?
4. A QAM constellation
has 8 points that can be incribed by two concentric circles. How many different
ampitudes does this system send in the physical channel? How many
phases?
5. Describe how
the UART in an RS-232 serial interface knows when to start and stop decoding
data pulses (data bits)