ISRO Scientist/Engineer CS Solved Papers

The noise phenomena arranged in the order of their dominance when plotted as a function of increasing frequency are:

When a carrier is AM modulated by three single tone signals of modulation percentages $50\%$, $50\%$ and $20\%$, then the effective modulation index of the resulting signal is:

$8$ signals, each limited to $2\text{ kHz}$ and sampled at Nyquist rate, are converted into binary PCM signal using $256$ quantization levels. The data rate for TDM signal will be:

The bandwidth occupied by an 8 PSK modulated signal, where each of the I, Q and C data streams which form the n-tuple IQC toggle at a rate 200 Mbps, is:

Given that CNDR of 256 QAM signal operating at $12.5\text{ M Symbols/s}$ is $100\text{ dBHz}$. The value of $E_b/N_0$ (Energy-per-bit to Noise Density ratio) is:

Return loss of a stand-alone antenna is $10\text{ dB}$. One $6\text{ dB}$ attenuator with return loss of $40\text{ dB}$ is connected at the input of that antenna. What will be the approximate return loss of the combined (Antenna + Attenuator) port?

Which parameter of semiconductor diode exhibits positive temperature co-efficient?

If a transistor operates at the middle of the dc load line, an increase in the current gain will move the Q point

The relation between $I_D$ and $V_{gs}$ of a MOSFET in the saturation region is

Random variable $x$ is with uniform distribution in the span $[-4, 1]$, mean and variance of $x$ is

Transfer function $H(s) = 1/(s + 3)^2$ has poles

An LTI system is minimum phase if

Given a real sequence and 8 point DFT output are $X(0) = 5,$ $X(1) = 1 + j,$ $X(2) = 3 + j,$ $X(3) = 2 + 3j$. What is $X(6)$?

Which is the identity for convolution operation?

Which of the following is NOT TRUE, given that “$\rightarrow$” represents fourier transform, “$*$” represents convolution, $x(n) \rightarrow X(e^{j\omega})$ and $y(n) \rightarrow Y(e^{j\omega})$?

The butterfly in the figure is taken from radix 2 decimation in time FFT with $N = 32$. Assume that the five stages of the signal flow graph are indexed by $m = 1, 2, 3, 4, 5,$ where 5 is the last stage. Which of the five stages has butterflies of this form?

If A & B are 8 bit right shift registers connected as shown in fig. and the initial values of A & B in hexadecimal are B2 and 0F respectively, the value of A in hexadecimal after 6 clock pulses is:

What is the quantization noise power for N bit uniform quantizer with full scale input voltage 2B?

Simplified Boolean function $f(A, B, C, D) = \sum (0, 2, 4, 5, 6, 7, 8, 10, 13, 15)$ in POS form is:

Two systems $h_1[n] = A(b_1)^n u[n]$ and $h_2[n] = A(b_2)^n u[n]$ are cascaded. If the effective $H(z) = \frac{4}{4 - z^{-2}}$, find a possible value of $(A, b_1, b_2)$:

The inputs to a digital circuit are signals A, B and C. $\overline{A}$, $\overline{B}$ and $\overline{C}$ are not available. The $+5\text{V}$ supply and the ground can be used as logic '1' and '0' inputs respectively. To implement a function $\overline{B}\,\overline{C} + A\overline{C}$ using only 2:1 multiplexer, minimum number of MUX required is:

Which of the following is not true in VHDL?

A 4 bit unipolar DAC with 10V reference is fed to the input of a comparator, whose threshold is set as 7.5V. When the DAC counts from 0 and reaches 8, the comparator showed threshold crossing wrongly. It is found that one of the DAC input bit is stuck at '1'. Which is the stuck at '1' bit?

Resistors R1, R2 and R3 are connected in series across a voltage source 'V' and R4 is connected in parallel with R3. R1 to R4 are to be chosen from available resistor values 3 Ω, 6 Ω, 10 Ω and 15 Ω. What will be the ratio of maximum current to minimum current through R1 by choosing resistor values appropriately?

A system is defined by the difference equation:

then the system is