In delta modulation, the slope overload distortion can be reduced by
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Digital Communication
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Let x(t) = 2cos(800πt) + cos(1400πt).x(t) is sampled with the rectangular pulse train shown in the figure. The only spectral components (in kHz) present in the sampled signal in the frequency range 2.5 kHz to 3.5 kHz are
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If Eb, the energy per bit of a binary digital signal, is 10-5 Watt-sec and the one-sided power spectral density of the white noise, N0 = 10-6 W/Hz, then the output SNR of the matched filter is
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In a digital communication system employing Frequency Shift Keying (FSK), the 0 and 1 bit are represented by sine waves of 10 kHz and 25 kHz respectively. These waveforms will be orthogonal for a bit interval of
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If the number of bits per sample in a PCM system is increased from a n to n + 1, the improvement in signal to quantization nose ratio will be
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Flat top sampling of low pass signals
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The input to a matched filter is given by
s\left( t \right) = \left\{ {\begin{array}{*{20}{c}} {10\sin \left( {2\pi \times {{10}^6}} \right)}&{0 < t < {{10}^{ - 4}}\sec } \\ 0&{{\text{Otherwise}}} \end{array}} \right.
The peak amplitude of the filter output is
s\left( t \right) = \left\{ {\begin{array}{*{20}{c}} {10\sin \left( {2\pi \times {{10}^6}} \right)}&{0 < t < {{10}^{ - 4}}\sec } \\ 0&{{\text{Otherwise}}} \end{array}} \right.
The peak amplitude of the filter output is
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At a given probability of error, binary coherent FSK is inferior to binary coherent PSK by
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For a bit-rate of 8 Kbps, the best possible values of the transmitted frequencies in a coherent binary FSK system are
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In the following figure the minimum value of the constant "C", which is to be added to y1(t) such that y1(t) and y2(t) are different, is
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A signal x(t) = 100cos(24π × 103)t is ideally sampled with a sampling period of 50 psec and then passed through an ideal lowpass filter with cutoff frequency of 15 kHz. Which of the following frequencies is/are present at the filter output?
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In the output of a DM speech encoder, the consecutive pulses are of opposite polarity during time interval t1 ≤ t ≤ t2. This indicates that during this interval
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A BPSK scheme operating over an AWGN channel with noise power spectral density of uses equiprobable signals
and
over the symbol internal (0, T). If the local oscillator in a coherent receiver is ahead in phase by 45° with respect to the received signal, the probability of error in the resulting system is
and
over the symbol internal (0, T). If the local oscillator in a coherent receiver is ahead in phase by 45° with respect to the received signal, the probability of error in the resulting system is
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Consider a sample signal
where x(t) = 10cos(8π × 103)t and Ts =100 μsec. When y(t) is passed through an ideal lowpass filter with a cutoff frequency of 5 kHz, the output of the filter is
where x(t) = 10cos(8π × 103)t and Ts =100 μsec. When y(t) is passed through an ideal lowpass filter with a cutoff frequency of 5 kHz, the output of the filter is
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The Nyquist sampling frequency (in Hz) of a signal given by 6 × 104sinC3(400t) ∗ 106sinC3(100t) is
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In a PCM system, if the code word length is increased from 6 to 8 bits, the signal to quantization noise ratio improves by the factor
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Three analog signals, having bandwidths 1200 Hz, 600 Hz and 600 Hz, are sampled at their respective Nyquist rates, encoded with 12-bit words, and time division multiplexed. The bit rate for the multiplexed signal is
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The peak-to-peak input to an 8-bit PCM coder is 2 Volts. The signal power-to-quantization noise power ratio (in dB) for an input of 0.5cos(ωmt) is
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The Nyquist sampling rate for the signal is given by
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The bit rate of digital communication system is R kbits/s. The modulation used is 32-QAM. The minimum bandwidth required for |S| free transmission is
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