B.TECH - Semester 4 data communication Question Paper 2022 (dec)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Mention the purpose of cladding in Optical Fibers
- Encode the given bil stream using NRZ and NRZ-1 100010001111.
- What is meanl by Transmission impaiments?
- What is the channel capacity for a teleprinter channel with a 300 Hz bandwidth and a signal-lo- noise ratio of 3 dB , where the noise is white thermal noise?
- Wrile short notes on Hamming codes. ( $5 \times 4=20$ Marks)
- (a) Distinguish bebween Terrestrial microwaves and Salellie microwaves, 5
- (b) What is Bandwidth? A periodic signal has a Bandwidth of 20 Hz . The highest frequency is 60 Hz . What is the lowest frequency? Draw the spectrum if the signal contains all frequencies of same amplitude.
- (c) Compare the following
- (i) Iiali duplex and Full duplex transmission (ii) Synchronous TDM and Stalislical TDM.
- (a) Dislinguish between Attenualion and Delay distortion?
- (b) What is the thermal notse level of a channel with a bandwidth of 10 KHz carrying 1000 Watts of power operating at $50^{\circ} \mathrm{C}$.
- (c) Explain the structure applications and Iransmission characleristics of twisted pair and coaxial cable.
- (a) Consider a FSK transmitter using a carrier frequency of 500 KHz sending 10 Kbps and a frequency devialion of 100 KHz . How much bandwidth is needed for tints fransmission. Also find the bandwidth for a signal transmitting al 12 Mbps for QPSK. ( $...
- (b) List the adwantages of using biphase lechniques over NRZ schemes for encoding digilal dala.
- (c) Compare Synchronous and Asynchronous transmission.
- (a) With a neal sketch discuss the various sleps involved in PCM.
- (b) Given the bit pattern 101110001. Encode the stream using BFSK and QPSK.
- (c) Explain line various schemes for encoding analog dala inlo analog signals. 88
- (a) (i) Differentiale belween Synchronous TDM and Stalistical TDM. Why is a stalistical lime division mullipleker more efficient than a synchronous lime division multiplexer. (ii) Why would you expect a CRC lo delect more errors than a parily bit?4
- (b) Derive the Hamming code for a single bil error correction (For a data af length 7 bil)
- (c) Wrile short notes on 4
- (a) In a CRC error-delecling scheme, choose divisor polynomlal $\mathrm{P}: x^{4}+x+1$ Encode the bils 100100011011. B
- (b) Explain about convolution codes in data communicalion systems. 4
- (c) What is Frequency Division Mulliplexing? How is interference avoided by using FDM? 4
- (d) Whal is Forward Error Correclion? 4
- (a) Explain the following terms:
- (i) DSSS (ii) FHSS 6
- (b) What are the advanlages and disadvanlages of CDMA? 5
- (c) Explain the salient features of GPRS. OR
- (a) Consider a DS-BPSK spread spectrum transmitter, Lel $d(l)$ be a binary sequence 1101, arriving al a rale of 100 bps , where left most bit is the earliest bit. Lel c(1) be the pseudorandom binary sequence 100110111000 with a clock rate al 300 hz A...
- (i) Find the final transmitled binary sequence corresponding to the bipolar signal sequence, $p(t)$ (ii) What is the bandwidth of the transmilled spread spectrum (iii) Calculate the processing gain in dB.
- (b) Uthal are the advandages of packel swilching compared lo circuit switching. 7
- (c) Discuss the working of GSM.