This set of Video Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Digital Satellite Television”.
1. Which of the following technique is used to reduce the average data rate to about 3 to 6 Mbps in digital satellite television?
a) Data compression
b) Encryption
c) Packetizing
d) Transmission
View Answer
Explanation: In data compression technique the data rate required to transmit all the digital video and audio signal which is obtained from studio would need around 200 to 800 Mbps and a channel bandwidth of more than 50 MHz along with the extremely expensive process in equipment. Hence, data compression technique is used to reduce the average data rate to about 3 to 6 Mbps.
2. The data rate can vary from 50 Kbps for mono signal to nearly 500 Kbps for stereo sounds in digital satellite television.
a) True
b) False
View Answer
Explanation: The above statement is false. In data compression technique, audio compression is also done to reduce audio bit rate by ignoring soft sound that are near louds because their absence at the receiving end would not matter much. The resulting data rate can vary from 50 kbps for mono signal to nearly 300kbps for stereo sounds.
3. How are the encrypted signals decrypted by the satellite receiver in digital satellite television?
a) Proximity card
b) ATM card
c) Smart card
d) Magnetic stripe card
View Answer
Explanation: A card called “smart card” is used by the satellite receiver to decrypt the encrypted signals. For activating the “smart card” first time, it is inserted in the front panel slot and then the serial number of receiver is entered on it. This will prevent the card by activation from any other receiver.
4. Along with the audio and video signals, conditional data is also transmitted to the customers in data packet technique in digital satellite television.
a) True
b) False
View Answer
Explanation: In data packet technique along with the audio and video signals, conditional data is also transmitted to the customers. It includes conditional access data, computer compatible data and manuals. Each set is in the form of data packets. It is necessary, that all the data packets are time multiplexed into serial data before transmission.
5. Which of the following is controlled by the microcontroller with specific pulses for each channel in digital broadcast set-top-box?
a) Data packets
b) Video encoder
c) Tuner
d) Transport IC
View Answer
Explanation: In digital broadcast set-top-box the signal is received by the dish antenna and is applied to receiver decoder. In tuner demodulation the tuner is controlled by the microcontroller with specific pulses for each channel. Different channels are demodulated by demodulator to obtain original digital data stream.
6. Which of the following is the heart of data processing circuitry in digital broadcast set-top-box?
a) Tuner
b) Transport IC
c) Audio encoder
d) Video encoder
View Answer
Explanation: In digital broadcast set-top-box transport IC (Integrated circuit) is the heart of data processing circuitry. The function of transport IC is to isolate video, audio and data packets and send them to reception video and audio decoder.
Sanfoundry Global Education & Learning Series – Video Engineering.
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