Concept Flashcards

Contents

Concept Flashcards#

Flashcards#

1. What two conditions must be met for successful communication?

  • Line-of-sight (LOS)

  • Sufficient received power (or SNR above threshold)

2. What does the Friis equation calculate?

  • The received power at the antenna

3. Write the Friis equation.
\[ P_R = P_T G_T G_R \frac{\lambda^2}{(4\pi R)^2} \]
4. What happens to received power if distance doubles?

  • It decreases by a factor of 4

5. What happens to received power if transmitted power doubles?

  • It doubles

6. How do antenna gains affect received power?

  • They increase received power linearly

7. What is the relationship between frequency and wavelength?
\[ \lambda = \frac{c}{f} \]
8. Why do lower frequencies travel farther?

  • They have longer wavelengths, which increases received power

9. What units must distance be in when using the Friis equation?

  • Meters

10. What is SNR?

  • The ratio of signal power to noise power

11. Write the SNR equation.
\[ SNR = \frac{P_{signal}}{P_{noise}} \]
12. Write the thermal noise equation.
\[ P_{noise} = k T_{sys} BW \]
13. What increases noise power?

  • Higher temperature

  • Larger bandwidth

14. What is a decibel (dB)?

  • A logarithmic representation of a power ratio

15. Write the decibel equation.
\[ G_{dB} = 10 \log_{10}(G) \]
Contents