MODD / Mr. Hansen 10/6/2005

Name: _________________________

Test on Unit 0x20 (Topics 0x1C and 0x21-0x2F, omitting 0x29)

Time limit: 32 minutes (48 minutes for extended time). A calculator is permitted.
Each question is worth 5 points. Your name is worth 3 points.

Instructions for Part I: For multiple choice questions, write the capital letter of the best choice in the blank provided. For fill-in problems, write the word or phrase that best fits in the space provided.

___ 1.	All analog processes are characterized by . . .
	(A) continuous functions (B) step functions (C) polynomial functions	(D) written functions (E) exponential functions
___ 2.	All digital processes are characterized by . . .
	(A) continuous functions (B) step functions (C) polynomial functions	(D) written functions (E) exponential functions
___ 3.	The chief advantage of digital technology over analog technology is . . .
	(A) resistance to noise (B) encryptability (C) compressibility	(D) dynamic range (E) freedom from aliasing
___ 4.	Noise for our purposes is defined as . . .
	(A) loud sound (B) annoying sound (C) either A or B	(D) whispering (E) unwanted signal, tending to cause data corruption
___ 5.	ASCII stands for . . .
	(A) American Standard Computer Information Index (B) American Society for Computation, Information, and Integration (C) American Standard Code for Information Interchange (D) American Standard for Computer Information Interchange (E) American Standard Computer Index for Information
___ 6.	A 1-byte ASCII representation can be any of how many possibilities?
	(A) 2^1, or 2 (B) 2^8, or 256 (C) 2^10, or 1024	(D) 2^16, or 65,536 (E) 2^24, or 16,777,216
___ 7.	CD-quality digital audio requires 2 bytes per sample. The bit depth is . . .
	(A) 2 (B) 4 (C) 8	(D) 16 (E) 24
___ 8.	CD-quality digital audio, at 2 bytes per sample and 44,100 samples per second, has a sampling rate of . . .
	(A) 11.025 KHz (B) 22.05 KHz (C) 44.1 KHz	(D) 88.2 KHz (E) 176.4 KHz
___ 9.	Since 2 times 44,100 equals 88,200, one might think that CD-quality digital audio requires about 86 KB/sec. However, the actual figure is closer to 172 KB/sec. Why?
	(A) 2 bytes per sample (B) 2 nybbles per byte (C) 2 channels	(D) 2 bytes per word (E) none of these
___10.	The uncompressed CD digital audio format was chosen to accommodate Beethoven’s Ninth Symphony, a piece that requires a little over an hour to perform. About how many hours of music could be stored on a CD in MP3 format?
	(A) 6 (B) 12 (C) 24	(D) 48 (E) 96
11, 12.	Look at the block diagram on the board and write an appropriate label or abbreviation for the two numbered boxes.
	11. _________	12. _________
13-15.	Alexander Graham Bell (inventor of the ________________ ) and Thomas Edison (inventor of the phonograph) both used the changing strength of a sound wave to cause a change in their device. Bell transformed sound into a changing voltage, while Edison transformed sound into a moving etching needle (for recording). In playback, Edison’s device worked in reverse, transforming the moving needle into ________________ . Both Bell and Edison used ________________ technology.

Instructions for Part II: Write a few sentences for each question.

16.	Quantum theory holds that at the subatomic level, all energy levels are discrete steps. For example, it is believed that an electron can have different energy levels, but with nothing in between the levels. Explain briefly what this might mean for our discussion of digital and analog technology.
17.	If you were making a database of personal attributes, you might record such things as name, address, ZIP code, etc. Imagine an idealized database, in which quantities can be recorded as real numbers if necessary. Categorize each of the following as digital or analog concepts, and briefly explain why: age _____________________________________________________________ age to the nearest year _______________________________________________ height ___________________________________________________________ birthdate (MM/DD/YYYY) ____________________________________________ gender ___________________________________________________________
18-20.	Briefly explain the difference between AM and FM. Are these technologies analog or digital?