Modern Electronic Communication by Gary Miller Chapter 8 with Answers

Chapter 8 Digital Communication : Coding Technique

1	The advantage(s) of digital and/or data communications over analog include
	a. Noise performance
	b. Regeneration
	c. Digital signal processing
	d. All the above
2	In a S/H circuit, the time that it must hold the sampled voltage is
	a. Aperture time
	b. Acquisition time
	c. Flat-top time
	d. Dmin
3	Error signals associated with the sampling process are called
	a. Foldover distortion
	b. Aliasing
	c. Nyquist rate
	d. a and b
4	Which of the following is not a common RZ code?
	a. RZ-unipolar
	b. RZ-bipolar
	c. RZ-M
	d. RZ-AMI
5	In an asynchronous data system
	a. Both sender and receiver are exactly synchronized to the same clock frequency.
	b. Each computer word is preceded by a start bit and followed by a stop bit to frame the word.
	c. The receiver derives its clock signal from the received data stream.
	d. All the above.
6	A CD audio laser-disk system has a frequency bandwidth of 20 Hz to 20 kHz. The minimum sample rate to satisfy the Nyquist criteria is
	a. 20 Hz
	b. 20 kHz
	c. 40 Hz
	d. 40 kHz
7	With respect to converter circuits
	a. DACs include an ADC
	b. ADCs include a DAC
	c. DACs and ADCs are virtually identical
	d. All the above.
8	The type of modulation that uses sampling on one of the parameters of the transmitted and received signal is known as
	a. Phase modulation
	b. Pulse modulation
	c. Amplitude modulation
	d. Frequency modulation
9	An alphanumeric code for representing the decimal values from 0 to 9 that is based on the relationship that only one bit in a binary word changes for each binary step is known as
	a. ASCII
	b. EBCDIC
	c. Baudot code
	d. Gray code
10	The quantizing error of PCM systems for weak signals can be made less significant by
	a. Companding
	b. Using time-division multiplexing
	c. Using frequency-division multiplexing
	d. Filtering out the alias frequency
11	When the message and the BCC are transmitted as separate parts within the same transmitted code, it is called a(n)
	a. Systematic code
	b. CRC
	c.  (n,k) cyclic code
	d. Interleaved code
12	The value left in the CRC dividing circuit after all data have been shifted in is the
	a. Quantile interval
	b. Codec
	c. BCC
	d. Syndrome
13	Which of the following is not an example of code error detection and correction in a data communication channel?
	a. Parity
	b. Frequency-shift keying
	c. Block-check character
	d. Hamming code
14	Error-correcting techniques that allow for correction at the receiver are called
	a. Cyclic redundancy checks (CRC)
	b. Block-check characters (BCC)
	c. Forward error correcting (FEC)
	d. Parity
15	Codes producing random data that closely resemble digital noise are
	a. Systematic codes
	b. PN codes
	c. Pseudonoise codes

     d. b and c

Answers:

D

A

D

C

B

D

B

B

D

A

A

D

B

C

D