GATE EC ||COMMUNICATION SYSTEM||BASE BAND MODULATION|| PYQs (2000-2025)

A speech signal, bandlimited to 4 kHz and peak voltage varying between +5V and –5V, is sampled at the Nyquist rate. Each sampled is quantized and represented by 8 bits.

Assuming the signal to be uniformly distributed between its peak to peak value, the signal to noise ratio at the quantizer output is

(PYQ || 2008 MCQ || 2 MARK)

A message signal having peak-to-peak value of 2 V, root mean square value of 0.1 V and bandwidth of 5 kHz is sampled and fed to a pulse code modulation (PCM)

system that uses a uniform quantizer. The PCM output is transmitted over a channel that can support a maximum transmission rate of 50 kbps. Assuming that the

quantization error is uniformly distributed, the maximum signal to quantization noise ratio that can be obtained by the PCM system (rounded off to two

decimal places) is ____

(PYQ || 2021 NAT || 2 MARK)

A sinusoidal message signal is converted to a PCM signal using a uniform quantizer. The required signal to quantization noise ratio (SQNR) at the output of the quantizer is 40 dB. The minimum number of bits per sample needed to achieve the desired SQNR is ________.(in integer)

(PYQ || 2017 NAT || 1 MARK)

Which one of the following statements about differential pulse code modulation (DPCM) is true?

(PYQ || 2017 MCQ || 1 MARK)

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. The minimum bandwidth (in kHz) required for transmission is________. (rounded off to one decimal place)

(PYQ || 2016 NAT || 1 MARK)

A sinusoidal signal of amplitude A is quantized by a uniform quantizer. Assume that the signal utilizes all the representation levels of the quantizer. If the signals to quantization noise ratio is 31.8 dB, the number of levels in the quantizer is _______.(in integer)

(PYQ || 2015 NAT || 1 MARK)

A sinusoidal of 2 kHz frequency is applied to a delta modulator. The sampling rate and step-size Δ of the delta modulator are 20,000 samples per second and 0.1 V, respectively. To prevent slope overload, the maximum amplitude of the sinusoidal signal (in Volts) is

(PYQ || 2015 MCQ || 1 MARK)

An analog signal is band-limited to 4 kHz, sampled at the Nyquist rate and the samples are quantized into 4 levels. The quantized levels are assumed to be independent and equally probable. If we transmit two quantized samples per second, the information rate is

(PYQ || 2011 MCQ || 1 MARK)

The Nyquist sampling rate for the signal

(PYQ || 2010 MCQ || 2 MARK)

The number of quantization levels required to reduce the quantization noise by a factor of 4 would be

( PYQ || 2008 MCQ || 2 MARK)