SBCA Digital Transmission 3

Question 1

What is the Nyquist sampling theorem's requirement for lossless digital sampling of an analog signal?

Accepted Answer

Sample at least twice the highest frequency component

Answer

The Nyquist theorem states the sampling rate must be at least twice the highest frequency in the signal to allow perfect reconstruction.

Question 2

Which parameter directly determines the symbol rate (baud rate) of a satellite carrier?

Accepted Answer

Occupied bandwidth and roll-off factor

Answer

Symbol rate is set by the transponder's occupied bandwidth and the roll-off factor of the Nyquist filter shaping the signal.

Question 3

What does a BER (Bit Error Rate) of 10⁻⁶ mean in a digital satellite link?

Accepted Answer

One error per one million bits

Answer

BER of 10⁻⁶ means one bit error occurs for every one million bits transmitted, which is an acceptable threshold for many satellite services.

Question 4

In satellite broadcasting, what is the advantage of using statistical multiplexing over fixed bit-rate multiplexing?

Accepted Answer

It dynamically allocates bandwidth to maximize overall picture quality

Answer

Statistical multiplexing allocates more bits to complex, fast-moving scenes and fewer to static scenes, improving overall video quality within a fixed total bit rate.

Question 5

What is the role of an LDPC (Low-Density Parity-Check) code in DVB-S2?

Accepted Answer

Providing powerful inner forward error correction near Shannon limit

Answer

LDPC codes in DVB-S2 provide near-Shannon-limit error correction performance, enabling operation at very low Eb/No with high reliability.

(SBCA) Satellite Broadcasting and Communications Association Certification Practice Test

(SBCA) Satellite Broadcasting and Communications Association Certification Practice Test

SBCA Digital Transmission 3