Q1:

What is the ratio of modulating power to the total power at 100% AM modulation?

Q2:

A sinusoidal carrier signal of 1V, 100 KH_z is product modulated by a message signal of 1V,1 KH_z. The resulting signal is passed through HPF having cut off frequency of 100 KH_z. Filter O/P is added with IV, 100 KH_z&${90}^0$phase shift sinusoidal signal. Find envelope of resulting signal.

Q3:

A DSB-SC signal is to be generated with a carrier frequency f_c = 1 MHz using a non-linear device with the input-output characteristic $v_0=a_0{v}_i+a{v}_i^3$where a₀ and a₁ are constants, where $V_i=A_C\cos (2\pi f_{c}t)+m(t)$. The output of the non-linear device can be filtered by an appropriated band-pass filter.

Q4:

In FM signal with a modulation index $m_f$ is passed through a frequency tripler. The wave in the output of the tripler will have a modulation of

Q5:

An amplitude modulated signal with message signal frequency ${\omega }_m=1\frac{Krad}{\sec }$and modulation index $\mu =0.5$. The modulated signal is demodulated using an RC low pass filter as envelop detector with elements R and C. The maximum value of product RC (in msec) for proper envelop detection is---------------(Approx)

Q6:

In Modulation, “Carrier” is

Q7:

c(t) and m(t) are used to generate an FM signal. If the peak frequency deviation of the generated FM signal is three times the transmission bandwidth of the AM signal, then the coefficient of the term cos [2$\pi$(1008 × 10³t)] in the FM signal (in terms of the Bessel Coefficients) is

Q8:

Which of the following is a digital modulation technique

Q9:

The signal to quantization noise ratio in an n-bit PCM system

Q10:

In a delta modulation system, message signal quantized with a step size of 0.01V, sample at the rate of 100 samples/sec. Which of the following signal avoid slope overload distortion?

Q11:

Which one of the following is analog modulation

Q12:

A probability density function is given by p(x) = k exp(-x²/2),$-\infty <x<\infty$. the value of k should be.

Q13:

A memory less source emits n-symbols each with a probability P, the entropy of the source as a function of n.

Q14:

Assertion (A):- Entropy of a binary source is maximum if the probabilities of occurrence of both the events are equal.

Reason (R):- The average amount of information per source symbol is called entropy for a memory less source.

Q15:

A signal x(t) = 100 cos (24$\pi$ × 10³t) is ideally sampled with a sampling period of 50 $\mu$ sec and then passed through an ideal low pass filter with cut off frequency of 15 kHz. Which of the following frequencies are present at the filter output?

Q16:

Let X(t) be a white Gaussian noise with $S_X(f)=\frac{N_0}{2}$. Assume that X(t) is input to an LTI system with h(t) = $e^{-t}u(t)$.

Let Y(t) be the output.

Find $S_Y(f)$

Q17:

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

Q18:

A random variable X is uniformly distributed between -1 to 1 and another random variable Y independent of X is uniformly distributed between 0 to 5. A new random variable z = x + y. The probability density function of Z is.

Q19:

Total power of a random variable is 25 and DC power 16. then the coefficient of variance is

Q20:

Autocorrelation is maximum at _______