Lesson 21 Flashcards#
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1. What are the three ways we can represent an electrical signal?
An equation
A time-domain waveform
An amplitude spectrum (frequency-domain representation)
2. What is the frequency-domain representation of a signal?
A plot of amplitude versus frequency that shows the signal’s frequency content.
3. What two pieces of information are required to draw an amplitude spectrum of a sinusoid?
Amplitude and frequency.
4. Write the relationship between period and frequency.
5. How is a DC signal represented in the frequency domain?
As a vertical spike at \(0\ \text{Hz}\).
6. Why does a DC signal appear at 0 Hz in the spectrum?
Because it does not change with time, meaning its frequency is \(0\ \text{Hz}\).
7. Write the bandwidth equation.
8. When is the lowest frequency of a signal equal to 0 Hz?
When the signal contains a DC bias.
9. What is bandwidth in ECE 315?
The range of frequencies contained in a signal or passed by a system.
10. What does an ideal filter do?
It passes frequencies within its passband without changing amplitude or phase and completely removes frequencies outside the passband.
11. What does a Low Pass Filter (LPF) allow to pass?
Frequencies below the cutoff frequency \(f_{\text{c/o}}\).
12. What does a High Pass Filter (HPF) allow to pass?
Frequencies above the cutoff frequency \(f_{\text{c/o}}\).
13. What does a Band Pass Filter (BPF) allow to pass?
Frequencies between \(f_{\text{c/o,1}}\) and \(f_{\text{c/o,2}}\).
14. What does a Band Reject Filter (BRF) block?
Frequencies between \(f_{\text{c/o,1}}\) and \(f_{\text{c/o,2}}\).
15. Why are frequency-domain graphs often more useful than time-domain graphs for complex signals?
Because they clearly show the individual frequency components and make it easier to determine bandwidth and filtering effects.