Question

QUESTION 1

1. In an unguided electromagnetic telecommunications link, acoustic waves are transmitted and received by antennas operating at radio frequency (RF) frequencies.

True

False

10 points   

QUESTION 2

1. What is the best reason why we view signals in the time and frequency domains?

		a. the time domain tells us the bandwidth of the information signal, while the frequency domain gives us an idea of how often information is sent
		b. time domain signals show us the amplitude of the signal over time, while the frequency domains tells us which frequencies the signal is comprised of (i.e., frequency bandwidth)
		c. viewing the signal in the time domain is critical since it tells us the frequency and periodicity of the information signal, while the frequency domain gives us information regarding the amplitude of the signal over time
		d. None of the above are good reasons

10 points   

QUESTION 3

1. In the frequency domain, you view a signal whose highest frequency is f_H=10kHz, and lowest frequency is f_L=5000Hz. What is the signal’s frequency bandwidth?

		a. 15kHz
		b. 15,000 Hz
		c. 5kHz
		d. You must view the signal in the time domain to determine the signal bandwidth

10 points   

QUESTION 4

1. Select the correct statement(s) regarding periodic, aperiodic signals and frequency bandwidth.

		a. a signal containing information will typically appear as an aperiodic wave in the time domain, and will have an associated bandwidth in the frequency domain
		b. information signals will always appear as periodic waves in the time domain, and will be associated with a bandwidth in the frequency domain
		c. information signals will always appear as a periodic wave in the time domain, but will never be associated with a bandwidth in the frequency domain
		d. all of the statements are correct

10 points   

QUESTION 5

1. A transducer is a device that converts signal energy in one form, to another form (example: acoustic to electrical signal, electrical to a RF signal).

True

False

Answer 1

Answer:------

1. a. True
2. b. time domain signals show us the amplitude of the signal over time, while the frequency domains tells us which frequencies the signal is comprised of (i.e., frequency bandwidth)
3. c. Signal’s frequency bandwidth = [ highest frequency f_H=10kHz( 10000 Hz) ] - [ lowest frequency f_L=5000Hz ]
   10000 Hz - 5000 Hz = 5000 Hz = 5kHz
4. b. information signals will always appear as periodic waves in the time domain, and will be associated with a bandwidth in the frequency domain
5. True