GATE EC ||COMMUNICATION SYSTEM|| NOISES IN COMMUNICATION SYSTEM || PYQs (2000-2025)

An antenna pointing in a certain direction has a noise temperature of 50 K. The ambient temperature is 290K. The antenna is connected to a pre-amplifier that has a noise figure of 2 dB and an available gain of 40 dB over an effective bandwidth of 12MHz. The effective input noise temperature T e for the amplifier and the noise power P ao at the output of the preamplifier, respectively, are

(2016 MCQ || 2 MARK)

The noise at the input to an ideal frequency detector is white. The power spectral density of the noise at the output is

( PYQ || 2003 MCQ || 1 MARK)

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

(PYQ || 2003 MCQ || 2 MARK)

( PYQ || 2003 MCQ || 2 MARK)

A 1mW video signal having a bandwidth of 100 MHz is transmitted to a receiver through a cable that has 40 dB loss. If the effective one-sided noise spectral density at

the receiver is 10^ –20 Watt/Hz, then the signal-to-noise ratio at the receiver is

( PYQ || 2004 MCQ || 2 MARK)

Noise with uniform power spectral density of N 0 W/Hz is passed through a filter H (ω) = 2exp (–jωt d ) followed by an ideal low pass filter of bandwidth B Hz. The output

noise power in Watts is

(PYQ || 2005 MCQ || 2 MARK)

Noise with double-sided power spectral density of K over all frequencies is passed through a RC low pass filter with 3 dB cut-off frequency of f c . The noise power

at the filter output is

(PYQ || 2008 MCQ || 2 MARK)

The amplitude of a random signal is uniformly distributed between –5V and 5V.

If the signal to quantization noise ratio required in uniformly quantizing the signal is 43.5 dB, the step size of the quantization is approximately

(PYQ || 2009 MCQ || 2 MARK)

The amplitude of a random signal is uniformly distributed between –5V and 5V.

If the positive values of the signal are uniformly quantized with a step size of 0.05 V, and the negative values are uniformly quantized with a step size of 0.1 V,

the resulting signal to quantization noise ratio is approximately

(PYQ || 2009 MCQ || 2 MARK)

An analog voltage in the range 0 to 8 V is divided in 16 equal intervals for conversion to 4-bit digital output. The maximum quantization error (in V) is ________.

(Rounded off to two decimal places)

(PYQ || 2014 MCQ || 1 MARK)