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

Assertion (A): Nyquist rate of sampling is the theoretical minimum sampling rate at which the signal can be sampled and still be reconstructed from its samples. Reason (R): When the Nyquist rate sampling is used, only an ideal low pass filter can be used to extract signal x(t) from sampled signal xs(t). Code:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true, but (R) is not the correct explanation of (A)

C

(A) is true, but (R) is false.

D

(A) false, but (R) is true

Let x(t) = 2cos(800πt) + cos(1400πt).x(t) is sampled with the rectangular pulse train shown in the figure. The only spectral components (in kHz) present in the sampled signal in the frequency range 2.5 kHz to 3.5 kHz are
Digital Communication mcq question image

Digital Communication mcq question image

A

2.7, 3.4

B

3.3, 3.6

C

2.6, 2.7, 3.3, 3.4, 3.6

D

2.7, 3.3

A signal containing only two frequency components (3 kHz and 6 kHz) is sampled at the rate of 8 kHz, and then passed through a low pass filter with a cut-off frequency of 8 kHz. The filter output

A

Is an undistorted version of the original signal

B

Contains only the 3 kHz component

C

Contains the 3 kHz component and a spurious component of 2 kHz

D

Contains both the components of the original signal and two spurious components of 2 kHz and 5 kHz

Four voice signals. each limited to 4 kHz and sampled at Nyquist rate are converted into binary PCM signal using 256 quantization levels. The bit transmission rate for the time-division multiplexed signal will be

A

8 kbps

B

64 kbps

C

256 kbps

D

512 kbps

A 1 kHz sinusoidal signal is ideally sampled at 1500 samples/sec and the sampled signal is passed through an ideal low-pass filter with cutoff frequency 800 Hz. The output signal has the frequency

A

Zero Hz

B

0.75 kHz

C

0.5 kHz

D

0.25 kHz

A signal is sampled at 8 kHz and is quantized using 8-bit uniform quantizer. Assuming SNR_q for a sinusoidal signal, the correct statement for PCM signal with a bit rate of R is

A

R = 32 kbps, SNR_q = 25.8 dB

B

R = 64 kbps, SNR_q = 49.8 dB

C

R = 64 kbps, SNR_q = 55.8 dB

D

R= 32 kbps, SNR_q = 49.8 dB

If a continuous time signal x(t) with spectrum X(F) is sampled at a rate Fs=1/T samples per second, the spectrum of the sampled signal is _____________

A

Non periodic repetition

B

Non periodic non-repetition

C

Periodic repetition

D

None of the mentioned

A speech signal occupying the bandwidth of 300 Hz to 3 kHz is converted into PCM format for use in digital communication. If the sampling frequency is8 kHz and each sample is quantized into 256 levels, then the output bit the rate will be

A

3 kb/s

B

8 kb/s

C

64 kb/s

D

256 kb/s

A band pass signal extends from 1 KHz to 2 KHz. The minimum sampling frequency that is needed to retain all information of the sampled signal is ___________

A

1 KHz

B

2 KHz

C

3 KHz

D

4 KHz

Four signals each band limited to 5 kHz are sampled at twice the Nyquist rate. The resulting PAM samples are transmitted over a single channel after time division multiplexing. The theoretical minimum transmissions bandwidth of the channel should be equal to

A

5 kHz

B

20 kHz

C

40 kHz

D

80 kHz

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

Related Questions