Recent questions tagged digital-communications

The number of bits in a binary $\mathrm{PCM}$ system is increased from $n$ to $n+1$. As a result, the signal to quantization noise ratio will improve by a factor$\frac{n+...

(a) Capture effect is (b) Granular noise(c) Guard band isan $\text{AM}$ system a characteristics ofan $\text{FM}$ system occurs ina $\text{DM}$ system required ina $\text...

The bandwidth required for the transmission of a $\text{PCM}$ signal increases by a factor of _________ when the number of quantization levels is increased from $4$ to $6...

(a) Single side band(1) Envelope detector(b) Amplitude(2) Integrate and dump modulation(c) Binary phase-shift(3) Hilbert transform keying (4) Ratio detector (5) Phase-loc...

The raised cosine pulse $p(t)$ is used for zero ISI in digital communications. The expression for $p(t)$ with unity roll-off factor is given by $p(t)=\dfrac{\sin 4 \pi W ...

During transmission over a certain binary communication channel, bit errors occur independently with probability $p$. The probability of AT MOST one bit in error in a blo...

In a GSM system, $8$ channels can co-exist in $200 \; \mathrm{kHz}$ bandwidth using TDMA. A GSM based cellular operator is allocated $5 \; \mathrm{MHz}$ bandwidth. Assumi...

In a Direct Sequence CDMA system the chip rate is $1.2288 \times 10^{6}$ chips per second. If the processing gain is desired to be AT LEAST $100,$ the data ratemust be le...

Two $4$-ary signal constellations are shown. It is given that $\phi_{1}$ and $\phi_{2}$ constitute an orthonormal basis for the two constellations. Assume that the four s...

Two $4$-ary signal constellations are shown. It is given that $\phi_{1}$ and $\phi_{2}$ constitute an orthonormal basis for the two constellations. Assume that the four s...

Consider a Binary Symmetric Channel (BSC) with probability of error being $p$. To transmit a bit, say $1,$ we transmit a sequence of three $1\text{s}.$ The receiver will ...

Statement for Linked Answer Questions 54 and 55:Consider a baseband binary PAM receiver shown below. The additive channel noise $n(t)$ is white with power spectral densit...

The bit stream $01001$ is differentially encoded using $\text{'Delay and Ex OR'}$ scheme for $\text{DPSK}$ transmission. Assuming the reference bit as a $'1'$ and assigni...

Coherent demodulation of $\text{FSK}$ signal can be effected usingcorrelation receiverBandpass filters and envelope detectorsmatched filterdiscriminator detection.

Source encoding in a data communication system is done is order toenhance the information transmission ratereduce the transmission errorsconserve the transmitted powerfac...

For the signal constellation shown in figure below, the type of modulation is ___________.

A four-phase and an eight-phase signal constellation are shown in the figure below.For the constraint that the minimum distance between pairs of signal points be $d$ for ...

A four-phase and an eight-phase signal constellation are shown in the figure below. Assuming high $\text{SNR}$ and that all signals are equally probable, the additional a...

A symbol stream contains alternate $\text{QPSK}$ and $\text{16-QAM}$ symbols. If symbols from this stream are transmitted at the rate of $1$ mega-symbols per second, the ...

Consider communication over a memoryless binary symmetric channel using a $(7, 4)$ Hamming code. Each transmitted bit is received correctly with probability $(1 – \in),$ ...

A digital transmission system uses a ($7,4$) systematic linear Hamming code for transmitting data over a noisy channel. If three of the message-codeword pairs in this cod...

Consider a polar non-return to zero ($\text{NRZ}$) waveform, using $+2\:V$ and $-2\:V$ for representing binary ‘$1$’ and ‘$0$’ respectively, is transmitted in the presenc...

A digital communication system transmits a block of $N$ bits. The probability of error in decoding a bit is $\alpha$. The error event of each bit is independent of the er...

In a digital communication system, a symbol $S$ randomly chosen from the set $\left \{ s_{1},s_{2},s_{3},s_{4} \right \}$ is transmitted. It is given that $s_{1}=-3,s_{2}...

A binary baseband digital communication system employs the signal $$p(t) = \begin{cases}\large\frac{1}{\sqrt T_s},&0\leq t\leq T_s \\ \: 0, & \text{otherwise} \end{cases}...

A speech signal is sampled at $8$ $kHz$ and encoded into $PCM$ format using $8$ bits/sample. The $PCM$ data is transmitted through a baseband channel via $4$-level $PAM$....

An ideal band-pass channel $500 \: Hz –2000 \:Hz$ is deployed for communication. A modem is designed to transmit bits at the rate of $4800$ bits/s using $16-QAM$. The rol...

A digital communication system uses a repetition code for channel encoding/decoding. During transmission, each bit is repeated three times ($0$ is transmitted as $000$, a...