SSPI Satellite Network Design & Operations 2

Question 1

What is the primary advantage of a multi-beam satellite architecture over a single wide-beam design?

Accepted Answer

Higher frequency reuse and increased system capacity

Answer

Multi-beam satellites reuse frequencies across geographically separated beams, dramatically increasing total system throughput.

Question 2

In satellite link budgets, what does the term 'margin' refer to?

Accepted Answer

The difference between available and required Eb/N0 or C/N

Answer

Link margin is the excess signal-to-noise ratio above the minimum threshold needed for reliable communications.

Question 3

Which modulation scheme provides the best spectral efficiency for a satellite broadband system?

Accepted Answer

16-APSK

Answer

16-APSK encodes 4 bits per symbol, offering superior spectral efficiency compared to lower-order modulations at the cost of requiring higher C/N.

Question 4

What is the purpose of Adaptive Coding and Modulation (ACM) in a satellite broadband system?

Accepted Answer

To dynamically adjust modulation and coding rate based on link conditions

Answer

ACM optimizes throughput by using higher modulation orders in clear conditions and falling back to robust modes during rain fade.

Question 5

A geostationary satellite at 35,786 km altitude introduces approximately how much one-way propagation delay?

Accepted Answer

~240 ms

Answer

The speed of light (~3×10⁸ m/s) over ~35,786 km yields approximately 119 ms one-way, commonly rounded to ~240 ms round-trip.

(SSPI) Society of Satellite Professionals International Certification Practice Test