EC DC 2marksmarks, DIGITAL COMMUNICATION Question Bank, DC Short Answers – ECE 5th SEM Anna University. 0. By vish on. 2. DIGITAL COMMUNICATION. State sampling theorem. If a finite –energy signal satellite communication two marks question and answers QUESTION BANK. Subject Code: EC Subject Name: Digital Communication Techniques. Year/Sem: III/IV. UNIT I PULSE MODULATION. PART A (2 Marks).

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The pseudo noise sequences generated at the receiver and the transmitted must be same and.

EC Digital Communication – Two Marks and 16 Marks with Answers – All Units

Define spread spectrum communication Ans: In the raised cosine spectrum, the frequency response P f decreases rigital zero maks That is there is no abrupt transition. The bandwidth of frequency hop spread spectrum is very much large compared to direct sequences spread spectrum. The impulse response of. They have relatively short acquisition time. DPCM can have more than one bit of encoding the sample. Adaptive coding is used for speech coding at low bits rates.

EC2301 Digital Communication Question Bank – 16 Mark Questions | 5th Semester ECE Anna University

Hence higher frequencies take the form of lower frequencies. BCH codes are most extensive and powerful error correcting cyclic codes. Trellis diagram indicates transitions from current to next states. Write an expression for bandwidth of binary PCM with N messages each with a maximum frequency of fm Hz.


Since only one previous message bit is stored.

What is direct sequence spread spectrum modulation Ans. The detection of the signal also become difficult this distraction can be figital with the help of equalizer.

Mention the merits of DPCM. Most of the channels are made up of individual links in switched telephone network,the distortion induced depends upon 1 transmission characteristics of individual links 2 number of links in connection 8. To achieve the same bit error rate the coding gain is defined as. These systems bandwidth spreads are very large. The non zero output of the produce YH.

This is called quantization. What are the error detection and correction capabilities of hamming co d es? PDM represents the input signal amplitude in the form of width of the pulse. The storage hardware required by convolutional decoder is less since the block sizes are smaller.

How syndrome is calculated in Hamming codes and cyclic codes? It required wideband channel with small phase distortion. Optical Communication and Networks Question Bank Convolutional codes are not developed much as compared to block codes. Here v is the number of bits digotal to represent samples in PCM.

Write the futures of BCH Codes? What is meant by syndrome of linear block code?

The code efficiency is the ratio of message bits in a block to the transmitted bits for that block by the encoder i. This operation is equivalent to binary convolution coding.

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Code tree Trellis diagram 1 Code tree indicates flow of the coded signal along the nodes of the tree Trellis diagram indicates transitions from current to next states 2 Code tree is lengthy way of representing coding process Code trellis diagram is shorter or compact way of representing coding process Antijamming with the help of direct sequence spread spectrum signals.

What is the advantage of delta modulation over pulse modulation s c h emes? Mention the use of adaptive quantizer in adaptive digital waveform co d ing schemes. E Civil 5th Semester Question Convolutional code takes one message bits at a time and generates two or more encoded bits. What is meant by PCM? Dirac comb is nothing but a periodic impulse train in which the impulses are spaced by a time interval of Ts seconds.

Let the bit rate be f b and the frequency of carrier be f.

They are not useful for range and range-rate measurement. A bandlimited signal of finite energy, which has no frequency components higher than W Hz, may be completely recovered from the knowledge of its samples taken at the rate of 2W samples per second. What is BCH code?