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If r^{2} = x^{2} + y^{2} + z^{2} then the value of is
The potential (scalar) distribution is V = 10y^{4} + 20x^{3}. If ∈_{0} be the permittivity of free space, then the charge density 'p' at the point (0, 2) is
The skin depth of copper at a frequency of 3 GHz is 1 micron (10^{6} meter). At 12 GHz for a nonmagnetic conductor whose conductivity is 1/9 times that of copper, the skindepth would be
Shortest length of a 42 Ω air line required toproduce a reactance of j73Ω at 1 MHz when line is short circuited is
A transmission line of characteristic impedance 50Ω is terminated by a resistor 100Ω.
Q. The impedance at the voltage maximum position is
A transmission line of characteristic impedance 50Ω is terminated by a resistor 100Ω.
Q. The impedance at the voltage minimum position is
An EM wave travels in free space with the electric field component, E. = 100 e^{i(a866 +} ^{a5z)}a_{x} V/m and ω = 3 x 10^{8} rad/sec. The time average power in the wave is
Standard equation is,
A 50Ω characteristic impedance line is connected to a load which shows a reflection coefficient of 0.268. If V_{in} = 15 V, then the net power delivered to the load will be
A TEM wave impinges obliquely on a dielectricdielectric boundary (,). The angle of incidence for total reflection is
Match ListI (Nature of Polarization) with
ListII (Relationship Between X and Y components) for a propagating wave having crosssection in the XY plane and propagating along Zdirection and select the correct answer:
ListI
A. Linear
B. Left circular
C. Right circular
D. Elliptical
ListII
X and Y components are in same phase
X and Y components have arbitrary phase difference
Consider the following statements:
A 1 kHz sinusoidal signal is ideally sampled at 1400 samples/sec and the sampled signal is passed through an ideal lowpass filter with cutoff frequency 800 Hz. The output signal has the frequency kHz
Given that,
f_{m} = 1 kHz
f_{s} = 1.4 kHz
So, the output signal coli[..]iris two frequencies and they are
⇒(1.4 + 1) kHz and (1.4  1)I\Hz
⇒(2.4) kHz and (0.4) kHz
But, LPF has f_{c} = 0.8 kHz
So, only 0.4 kHz will appear in output
In a SSB modulation, the power spectral density of m(t) is given as
where a and W are constants. White Gaussian noise of zero mean and PSD of N_{0}/2 is added to SSB modulator wave at the receiver input. The (SNR) at the output of the receiver is,
(Where A_{c} = Carrier signal amplitude)
Average signal power = P_{av}
= aW
By using SSB modulation in the transmitter and coherent detection in the receiver, the (SNR)_{output} is given by
(SNR)_{output}
(where A_{c} carrier signal amplitude)
An angle modulated signal with carrier frequency ω_{c} = 2π x 10^{5} is described by the equation Q_{Am} (t) = 10 cos (ω_{c} t + 5 sin 3000 t + 10 sin 2000 πt)
The maximum frequency deviation is
The instantaneous frequency ω_{1} is given by
ω_{1} = ω_{c}+ 15000 cos 3000 t + 20000π cos 2000πt
Maximum frequency deviation,
Δω = 15000 20000 π
Hence,
= 12388 Hz
= 12.38 kHz
A frequency modulated wave is 100% modulated by 10 kHz modulating signal m(t). Then the bandwidth required is
In a FM wave, we are concerned only with frequency.100% modulation corresponds to the maximum frequency deviation which is equal to 75 kHz.
∴ B an dwidth(B.W)
= 2(Δf + fm)
= 2(75 + 10) kllz
= 170 kHz
A sinusoid x(t) = A cos2πf_{o}t is sampled at 5 times the Nyquist rate for 2.5 sec. A total of 250 samples are acquired value of f_{s} and f_{m} are given by
Sampling frequency,
f_{s} = 5 x (N quilt rate)
= 5 x f_{0}= 10f_{0}
No of samples = = T x f_{s}
⇒ 250 = 2,5 x f_{s}
The anglemodulated signal with carrier frequency ω_{c} = 27c x 10^{6} is discribed by the equation
v(t) = 10 cos(ω_{c}t + 10sin200t + 20si n400πt) The deviation ratio is
A PCM system uses a uniform quantizer followed bya 7bit binary encoder. The bit rate of the system is equal to 50 x 10^{6} bps.
Q. The maximum message bandwidth for which the system oeprates satisfactorily, is
Maximum message bandwidth =
The approximate output signal  to (quantization) noise ratio when a full  load sinusoidal modulating wave of frequency 1 MHz is applied to the input, is
Output signal to (quantization) noise ratio
where, 0 2^{n} (where n = number of bits)
For an AM wave, the maximum voltage was found to be 10 V and the minimum voltage was found to be 5 V. The modulation index of the wave would be
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