41. A pure ALOHA network transmits 200 bit frames on a shared channel of 200 kbps . If the system with all stations together produces 1000 frames/s , the throughput is: (Assuming 𝑆 =0.135 (13.5%))

(a) 135 frames
(b) 140 frames
(c) 145 frames
(d) 150 frames

Answer: (a)

42. A network using CSMA/CD has a bandwidth of 10 Mbps. If the maximum propagation time including the delays in the devices and ignoring the time needed to send a jamming signal is 25.6 𝜇s, the minimum size of the frame is:
(a) 256 bits
(b) 1024 bits
(c) 128 bits
(d) 512 bits

Answer: (d)

43. The data rate of an STS-1 signal is:
(a) 155.52 Mbps
(b) 51.84 Mbps
(c) 100 Mbps
(d) 150 Mbps

Answer: (b)

44. 
(a) 08 bytes
(b) 16 bytes
(c) 02 bytes
(d) 12 bytes

Answer: (d)

45. In a stop-and-Wait system, the bandwidth of the line is 1 Mbps , 1 bit takes 20 ms to make a round trip and the system data packets are 1000 bits in length. The bandwidth-delay product and the utilization of the link are:
(a) 10,000 bits and 5 %
(b) 20,000 bits and 10 %
(c) 10,000 bits and 10 %
(d) 20,000 bits and 5 %

Answer: (d)

46. The frequency 𝑓, peak-voltage amplitude 𝑉 and phase 𝜃 for the voltage waveform, 𝑣(𝑡)=6sin(2𝜋 10,000 𝑡 +30) are:
(a) 20 kHz ,6 volts and 45°
(b) 10 kHz ,6 volts and 30°
(c) 20 kHz ,3 volts and 30°
(d) 10 kHz ,3 volts and 45°

Answer: (b)

47. For a binary FSK signal with mark frequency of 49 kHz , space frequency of 51 kHz and an input bit rate of 2 kbps , the peak frequency deviation Δ𝑓, the minimum bandwidth 𝐵 and the baud, are:
(a) 3 kHz , 9 kHz and 1000
(b) 3 kHz , 9 kHz and 2000
(c) 1 kHz , 6 kHz and 2000
(d) 1 kHz , 6 kHz and 1000

Answer: (c)

48. What is the length of an ICMP data field for an Ethernet frame that is carrying an IP datagram with a 20 byte header, an ICMP message with a header length of 8 bytes and the Ethernet data field is 480 bytes long?
(a) 452 bytes
(b) 480 bytes
(c) 256 bytes
(d) 280 bytes

Answer: (a)

49. For a single-channel PCM system with sample rate 𝑓𝑠 = 6000 samples per second and 7 bit compressed PCM code, the line speed is:
(a) 42,000 bps
(b) 32,000 bps
(c) 22,000 bps
(d) 12,000 bps

Answer: (a)

50. For an UART receiving data at 1000 bps (f𝑏) with a receiver clock 16 times faster than the incoming data, the bit time, the receive clock rate and the maximum detection error are:
(a) 1 ms,8 kHz and 62.5 𝜇s
(b) 3 ms,8 kHz and 66.5 𝜇s
(c) 1 ms,16 kHz and 62.5 𝜇s
(d) 3 ms,16 kHz and 66.5 𝜇s

Answer: (c)