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The CORRECT option is (d) F/2D

To explain I would SAY: We KNOW that if we reduce the sampling rate simply by SELECTING every Dth value of x(n), the SIGNAL will be an aliased version of x(n), with a folding frequency of F/2D.

Correct answer is (a) True

For EXPLANATION: The input sequence x(n) is passed through a low pass filter, characterized by the impulse RESPONSE h(n) and a frequency response HD(ω), which IDEALLY satisfies the condition,

HD(ω)=1, |ω| ≤ π/D

=0, otherwise

Thus the filter eliminates the spectrum of X(ω) in the RANGE π/D < ω < π.

Right option is (a) True

Explanation: \(\bar{v}(n)\) can be VIEWED as a SEQUENCE OBTAINED by multiplying v(n) with a periodic train of IMPULSES p(n) with period D.

Right option is (a) True

Easy EXPLANATION: Given the fact that X(n) PRODUCES y(m), we note that x(n-n0) does not IMPLY y(n-n0) UNLESS n0 is a multiple of D. Consequently, the overall linear operation, that is linear filtering followed by down sampling on x(n) is not time invariant.

Correct answer is (d) LINEAR and time INVARIANT

For EXPLANATION: Although the filtering operation on X(n) is linear and time invariant, the down-sampling operation in combination with the filtering results in a time variant SYSTEM.

Correct choice is (b) F/2D

For explanation I WOULD say: To AVOID aliasing, we must reduce the bandwidth of X(n) to Fmax=F/2D. Then we MAY down-sample by D and thus avoid SAMPLING.

The correct choice is (c) Decimation

For explanation: The block DIAGRAM SHOWN in the figure is of sampling rate conversion by decimation by a FACTOR D TECHNIQUE.

The CORRECT answer is (b) INTERPOLATION

Best explanation: The process of INCREASING the sampling rate by an integer FACTOR I, i.e., up-sampling by I is CALLED as interpolation.

The correct choice is (b) I/D

The EXPLANATION is: The input signal X(N) is characterized by the sampling RATE Fx and he output signal y(m) is characterized by the sampling rate FY, then

Fy/Fx = I/D

where I and D are relatively prime integers.

The CORRECT answer is (a) True

The explanation is: The process of SAMPLING rate CONVERSION in the digital domain can be viewed as a linear filtering operation as illustrated in the given figure.

Right choice is (d) All of the mentioned

To explain I WOULD say: There are several applications of sampling rate CONVERSION in multi rate digital signal processing SYSTEMS, which INCLUDE the implementation of narrow BAND filters, quadrature mirror filters and digital filter banks.

Right ANSWER is (d) Signal distortion & Quantization effects

Easiest EXPLANATION: The major disadvantage by the GIVEN type of CONVERSION is the signal distortion introduced by the D/A CONVERTER in the signal reconstruction and by the quantization effects in the A/D conversion.

Correct option is (c) NEW sampling rate can be arbitrarily selected

For EXPLANATION: One apparent advantage of the given method is that the new sampling rate can be arbitrarily selected and NEED not have any SPECIAL relationship with the OLD sampling rate.

Right option is (d) D/A convertor, A/D convertor & Performing ENTIRELY in digital DOMAIN

The best EXPLANATION: Sampling rate conversion of a digital signal can be accomplished in one of the two general methods. One method is to pass the signal through D/A converter, filter it if necessary, and then to resample the RESULTING analog signal at the desired rate. The second method is to perform the sampling rate conversion entirely in the digital domain.

Right ANSWER is (B) False

To elaborate: In telecommunication systems that transmit and RECEIVE different types of SIGNALS, there is a requirement to process the various signals at different RATES commensurate with the corresponding bandwidths of the signals.

Correct ANSWER is (c) Sampling rate conversion

The best I can explain: The process of CONVERTING a signal from a GIVEN rate to a DIFFERENT rate is known as sampling rate conversion.