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