chapter2

The lowest note possible on the piano is ____ Hz, and the highest note possible is 4200 Hz. a. 30 c. 300 b. 80 d. 450

a. 30

___ are represented as continuous waveforms that can be at an infinite number of points between some given minimum and maximum. a. Analog signals c. Digital data b. Digital signals d. Digital pulses

a. Analog signals

____ is an 8-bit code allowing 256 possible combinations of textual symbols. a. EBCDIC c. NRZI b. Unicode d. UTF-9

a. EBCDIC

____ modulation, which is commonly employed in contemporary modems, uses each signal change to represent 4 bits. a. Quadrature amplitude c. Quadrature noise b. Quadrature frequency d. Quadrature phase

a. Quadrature amplitude

The simplest modulation technique is ____ shift keying. a. amplitude c. frequency b. phase d. noise

a. amplitude c.

Unfortunately, noise itself occurs as a(n) ____ waveform, and this makes it challenging, if not extremely difficult, to separate noise from an analog waveform that represents data. a. analog c. hertz b. digital d. byte

a. analog

The data rate is measured in ____. a. bits per second (bps) c. bauds per second (bps) b. bytes per second (Bps) d. hertz per second (hps)

a. bits per second (bps)

When a signal is amplified by an amplifier, the signal gains in ____. a. decibels c. bytes b. hertz d. watts

a. decibels

The ____ encoding scheme has a voltage change at the beginning of a 1 and no voltage change at the beginning of a 0. a. nonreturn to zero inverted (NRZI) c. Manchester b. nonreturn to zero-level (NRZ-L) d. Differential Manchester

a. nonreturn to zero inverted (NRZI)

Tracking an analog waveform and converting it to pulses that represent the wave's height above (or below) a threshold is termed ____. a. pulse amplitude modulation (PAM) c. quantization b. codec d. quantization levels

a. pulse amplitude modulation (PAM)

The Greek symbol has the Unicode value of hexadecimal ____. a. 01F3 c. 05E4 b. 03B2 d. C108

b. 03B2

The bandwidth of a telephone system that transmits a single voice in the range of 300 Hz to 3400 Hz is ____ Hz. a. 10 c. 3100 b. 100 d. 3700

b. 100

____ is entities that convey meaning within a computer or computer system. a. Signals c. Impulse b. Data d. EMI

b. Data

____ is the process of sending data over a signal by varying either its amplitude, frequency, or phase. a. Amplification c. Attenuation b. Modulation d. Digital encoding

b. Modulation

____ shift keying represents 0s and 1s by different changes in the phase of a waveform. a. Amplitude c. Frequency b. Phase d. Noise

b. Phase

The amplitude of a signal can be expressed as volts, ____, or watts. a. hertz c. bits b. amps d. bytes

b. amps

The number of times a signal changes value per second is called the ____ rate. a. hertz c. watts b. baud d. volts

b. baud

Using ____, when a device transmits a binary 0, a zero voltage is transmitted. When the device transmits a binary 1, either a positive voltage or a negative voltage is transmitted. a. Manchester c. differential Manchester b. bipolar-AMI d. NRZ-L

b. bipolar-AMI

Cycles per second, or frequency, is represented by ____. a. bytes c. bits b. hertz d. watts

b. hertz

When converting analog data to digital signals, the frequency at which the snapshots are taken is called the ____ rate. a. baud c. bps b. sampling d. byte

b. sampling

The Manchester encoding schemes solve the synchronization problem but are relatively inefficient because they have a baud rate that is ____ the bps. a. equal to c. three times b. twice d. four times

b. twice

The primary advantage of a bipolar scheme is that when all the voltages are added together after a long transmission, there should be a total voltage of ____. a. -2 c. 0 b. -1 d. 1

c. 0

The frequency range of the average human voice usually goes no lower than 300 Hz and no higher than approximately ____ Hz. a. 2200 c. 3400 b. 2400 d. 5300

c. 3400

Three important data codes are EBCDIC, ____, and Unicode. a. NRZ-L c. ASCII b. 4B/5B d. NRZI

c. ASCII

The ____ is a government standard in the United States. a. UTF-8 b. EBCDIC c. American Standard Code for Information Interchange (ASCII) d. Unicode

c. American Standard Code for Information Interchange (ASCII)

___ are discrete waveforms, rather than continuous waveforms. a. Analog signals c. Digital signals b. Analog bauds d. Analog data

c. Digital signals

The ____ digital encoding scheme is similar to the Manchester scheme in that there is always a transition in the middle of the interval. a. NRZ-L c. differential Manchester b. Bipolar-AMI d. NRZI

c. differential Manchester

Frequency shift keying is subject to ____. a. baud noise c. intermodulation distortion b. bps distortion d. noise spikes

c. intermodulation distortion

One encoding technique that converts analog data to a digital signal is ____. a. NRZ-L c. pulse code modulation (PCM) b. Manchester d. NRZ-I

c. pulse code modulation (PCM)

If you want to transfer data from one point to another, either via a physical wire or through radio waves, the data has to be converted into a(n) ____. a. hertz c. signal b. Unicode d. byte

c. signal

The ASCII character set exists in a few different forms, including a ____ version that allows for 128 possible combinations of textual symbols. a. 3-bit c. 6-bit b. 5-bit d. 7-bit

d. 7-bit

____ shift keying incorporates four different phase angles, each of which represents 2 bits. a. Quadrature amplitude c. Quadrature noise b. Quadrature frequency d. Quadrature phase

d. Quadrature phase

The most common example of ____ data is the human voice. a. sampling c. digital b. baud d. analog

d. analog

When traveling through any type of medium, a signal always experiences some loss of its power due to friction. This loss of power, or loss of signal strength, is called ____. a. amplification c. decibel b. friction d. attenuation

d. attenuation

With ____, a codec tracks the incoming analog data by assessing up or down "steps." a. differential Manchester c. NRZI b. Bipolar-AMI d. delta modulation

d. delta modulation

The ____ of a signal is the number of times a signal makes a complete cycle within a given time frame. a. phase c. period b. amplitude d. frequency

d. frequency

A device that modulates digital data onto an analog signal and then demodulates the analog signal back to digital data is a ____. a. repeater c. hub b. switch d. modem

d. modem

The three basic components of analog and digital signals are: amplitude, frequency, and ____. a. cycles c. hertz b. baud d. phase

d. phase

Three currently popular modulation techniques for encoding digital data and transmitting it over analog signals are amplitude shift keying, frequency shift keying, and ____ shift keying. a. noise c. strength b. baud d. phase

d. phase

The Manchester encoding schemes are called ____, because the occurrence of a regular transition is similar to seconds ticking on a clock. a. continuous-clocking c. discrete-clocking b. analog-clocking d. self-clocking

d. self-clocking