List of practice Questions

NRZ and QPSK are respectively
Let an error control system uses (16, 3) block codes. The coding efficiency of the system will be
A direct sequence spread spectrum technique uses 10 flip-flop linear feedback shift register as PN code generator. The jamming margin produced by the system will be
Which of the following statements is true about error detection techniques used on communications link?
Which of the following Light source is popularly used in optical communication?
The Numerical aperture of a fiber describes the __________ characteristics.
When mean optical power launched into an 8 km length of fiber is 12 \(\mu\)W, the mean optical power at the fiber output is 3 \(\mu\)W. Find the overall signal attenuation in dB
The orthogonal signals S1 and S2 satisfy the following relation.
In a PCM system, speech signal bandlimited to 4 kHz is sampled at 1.5 times Nyquist rate and quantized using 256 levels. The bit rate required to transmit the signal will be
If the data rate of delta modulator output is 43.2 kbps, for the input signal of 3.6 kHz, then the sampling rate used is equal to,
An AM modulator develops an unmodulated power output of 400W across a 50\(\Omega\) resistive load. The carrier is modulated by a single tone with a modulation index of 0.6. If this AM signal is transmitted, the power developed across the load is
The Modulating frequency in narrow band frequency modulation is increased from 10 kHz to 20 kHz. The bandwidth is
The shape of the rectangular window function is changed to other function such as Hamming and Blackman window functions so that
Window function used in FIR realization,
The new pole locations due to truncation of coefficient to 4 bit including sign bit in the cascade realization \[ H(z) = \frac{1}{(1-0.95z^{-1})(1-0.25z^{-1})} \]
The number 110000000.010.....000 represented in IEEE single precision format corresponds to the decimal number
The transfer function of first order high pass digital Butterworth filter that has 3dB cut off frequency \( \omega = 0.15\pi \) using bilinear transformation with T=1s
The signal to quantization noise ratio of an analog to digital converter having full scale range of ±1 volt for seven bit word length is 42dB. The approximate value of signal to quantization noise ratio for 9 bit word length is
The output noise variance due to an 8-bit ADC of a first-order filter with \[ H(z) = \frac{1}{1 - 0.25z^{-1}} \] for the input signal with noise variance \( \sigma^2 \) is
The resultant magnetic flux generated in the closed surface will be

The motion of electrons in a CRT is due to:

H in the region \( 0 \leq l \leq a \) for an infinitely long co-axial transmission line is:

The direction of current flow in the circuit is such that the induced magnetic field produced by the induced current will oppose the original magnetic field. This is:

The electromagnetic wave propagates in free space with a speed of:

Energy stored in the capacitor is: