# Noise In Digital Communication · Communications · GATE ECE

Start Practice## Marks 1

GATE ECE 2017 Set 2

A sinusoidal message signal is converted to a PCM signal using a uniform quantizer. The required signal to quantization noise ratio (SQNR) at the outp...

GATE ECE 2016 Set 3

A binary baseband digital communication system employs the signal
$$$p\left( t \right) = \left\{ {\matrix{
{{1 \over {\sqrt {{T_s}} }},} & {0...

GATE ECE 2015 Set 2

A sinusoidal signal of amplitude A is quantized by a uniform quantizer. Assume that the signal
utilizes all the representation levels of the quantizer...

GATE ECE 2014 Set 1

The capacity of a Binary Symmetric Channel (BSC) with cross - over probability 0.5 is ______ .

GATE ECE 2010

Consider the pulse shape s(t) as shown. The impulse response h(t) of the filter matched to this pulse is
...

## Marks 2

GATE ECE 2016 Set 1

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

GATE ECE 2016 Set 1

An analog pulse s(t) is transmitted over an additive white Gaussian noise (AWGN) channel. The received signal is r(t) = s(t) + n(t), where n(t) is add...

GATE ECE 2015 Set 2

Consider a binary, digital communication system which uses pulses g (t) and − g (t)for transmitting bits over an AWGN channel. If the receiver uses a ...

GATE ECE 2015 Set 1

The input X to the Binary Symmetric Channel (BSC) shown in the figure is ‘1’ with probability 0.8. The cross-over probability is 1/7. If the received...

GATE ECE 2015 Set 1

A source emits bit 0 with probability $${1 \over 3}$$ and bit 1 with probability $${2 \over 3}$$. The emitted bits are
communicated to the receiver. T...

GATE ECE 2014 Set 4

Consider a discrete-time channel Y = X + Z, where the additive noise Z is signal- dependent. In particular, given the trasmitted symbol $$X\, \in \,\{...

GATE ECE 2014 Set 4

Consider a communication scheme where the binary valued signal X satisfies P{X = + 1} = 0.75 and P {X = - 1} = 0.25. The received signal Y = X + Z, wh...

GATE ECE 2014 Set 2

Coherent orthogonal binary FSK modulation is used to transmit two equiprobable symbol waveforms $${s_1}\,(t)\, = \,\alpha \,\,\cos \,\,\,2\,\pi {f_1}...

GATE ECE 2013

Let U and V be two independent zero mean Gaussian random variables of variances $${{1 \over 4}}$$ and $${{1 \over 9}}$$ respectively. The probability ...

GATE ECE 2012

A BPSK scheme operating over an AWGN channel with noise power spectral density of N02, uses equi-probable signals
$$${s_1}\left( t \right) = \sqrt ...

GATE ECE 2012

A binary symmetric channel (BSC) has a transition probability of 1/8. If the binary transmit symbol X is such that P(X =0) = 9/10, then the probabi...

GATE ECE 2011

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 ...

GATE ECE 2011

A four phase and an eight-phase signal constellation are shown in the figure below.
Assuming high SNR and that all signals are equally probable, ...

GATE ECE 2010

Consider a base band binary PAM receiver shown below. The additive channel noise
$$n(t)$$ is white with power spectral density $${S_N}\left( f \right)...

GATE ECE 2010

Consider a base band binary PAM receiver shown below. The additive channel noise
$$n(t)$$ is white with power spectral density $${S_N}\left( f \right)...

GATE ECE 2009

The amplitude of random signal is uniformly distributed between $$-$$5V and 5V
If the signal to quantization noise ratio required in uniformly quanti...

GATE ECE 2009

The amplitude of random signal is uniformly distributed between $$-$$5V and 5V
If the positive values of the signal are uniformly quantized with a st...

GATE ECE 2008

Consider a Binary Symmetric Channel (BSC) with probability of error being 'p'. To transit a bit, say 1, we transmit a sequence of three 1s. The receiv...

GATE ECE 2007

During transmission over a certain binary communication channel, bit errors occurs independently with probability p. The probability of at most one bi...

GATE ECE 2007

An input to a 6-level quantizer has the probability density function f(X) as shown in the figure. Decision boundaries of the quantizer are chosen so a...

GATE ECE 2007

An input to a 6-level quantizer has the probability density function f(X) as shown in the figure. Decision boundaries of the quantizer are chosen so a...

GATE ECE 2007

Two 4-ray signal constellations are shown. It is given that $${\phi _1}$$ and $${\phi _2}$$ constitute an orthonormal basis for the two constellations...

GATE ECE 2007

Two 4-ray signal constellations are shown. It is given that $${\phi _1}$$ and $${\phi _2}$$ constitute an orthonormal basis for the two constellations...

GATE ECE 2006

In the following figure the minimum value of the constant “C”, which is to be added to y1(t) such that y1(t) and y2(t) are different, is
...

GATE ECE 2006

Let $$g\left( t \right){\mkern 1mu} {\mkern 1mu} \,\,\,\,\,{\mkern 1mu} = {\mkern 1mu} {\mkern 1mu} p\left( t \right){}^ * p\left( t \right)$$ where...

GATE ECE 2005

A signal as shown in figure is applied to a matched filter. Which of the following does represent the output of this matched filter?
...

GATE ECE 2005

A symmetric three-level midtread quantizer is to be designed assuming equiprobable occurrence of all quantization levels.
The quantization noise power...

GATE ECE 2005

A symmetric three-level midtread quantizer is to be designed assuming equiprobable occurrence of all quantization levels.
If the input probability de...

GATE ECE 2004

Consider a binary digital communication system with equally likely $$0’s$$ and $$1’s$$.
When binary $$0$$ is transmitted the voltage at the detector i...

GATE ECE 2003

If Eb, the energy per bit of a binary digital signal, is 10-5 watt-sec and the one-sided power spectral density of the white noise, N0 = 10-6 W/Hz, th...

GATE ECE 2003

A sinusoidal signal with peak-to-peak amplitude of 1.536V is quantized into 128 levels using a mid-rise uniform quantizer. The quantization-noise powe...

GATE ECE 2001

During transmission over a communication channel, bit errors occur independently with probability 'p'. If a block of n bits is transmitted, the probab...

GATE ECE 1999

The peak-to-peak input to an 8-bit PCM coder is 2 volts . The signal power - to -quantization noise power ratio (in dB) for an input of 0.5 $$\cos \le...

GATE ECE 1999

The input to a matched filter is given by
$$$S\left( t \right) = \left\{ {\matrix{
{10\sin \left( {2\pi \times {{10}^6}t} \right),} & {0 <...

GATE ECE 1988

A signal having uniformly distributed amplitude in the interval ( -V, +V ) is to be encoded using PCM with uniform quantization. The signal - to - qua...

GATE ECE 1988

In a digital communication system, transmissions of successive bits through a noisy channel are assumed to be independent events with error probabilit...

GATE ECE 1987

Companding in PCM systems leads to improved signal - to - quantization noise ratio. This improvement is for