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?

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

A BPSK scheme operating over an AWGN channel with noise power spectral density of $$\frac{{{N_0}}}{2},$$  uses equiprobable signals
$${s_1}\left( t \right) = \sqrt {\frac{{2E}}{T}} \sin \left( {{\omega _c}t} \right)$$     and $${s_2}\left( t \right) = \sqrt {\frac{{2E}}{T}} \sin \left( {{\omega _c}t} \right)$$
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

Consider a sample signal
\[y\left( t \right) = 5 \times {10^{ - 6}}x\left( t \right)\sum\nolimits_{ - \infty }^{ + \infty } {\delta \left( {t - n{T_s}} \right)} \]
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

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

The Nyquist sampling rate for the signal $$s\left( t \right) = \frac{{\sin \left( {500\pi t} \right)}}{{\pi t}} \times \frac{{\sin \left( {700\pi t} \right)}}{{\pi t}}$$      is given by

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