PYQs Based Test - 11 : Communications

A symbol stream contains alternate QPSK and 16-QAM symbols. If symbols from this stream are transmitted at the rate of 1 mega-symbols per second, the raw (uncoded) data rate is _______ mega-bits per second (rounded off to one decimal place).

Which one of the following graphs shows the Shannon capacity (channel capacity) in bits of a memoryless binary symmetric channel with crossover probability p?

Consider a white Gaussian noise process N(𝑡) with two-sided power spectral density S${}_N$ (f) = 0.5 W/Hz as input to a filter with impulse response $0.5e^{-t^2/2}$ (𝑡 is in seconds) resulting in output Y(t). The power in Y(t), in watts, will be:

The unmodulated carrier power in an AM transmitter is 5 kW. This carrier is modulated by a sinusoidal modulating signal. The maximum percentage of modulation is 50%. If it is reduced to 40%, then the maximum unmodulated carrier power (in kW) that can be used without overloading the transmitter is _________

Let $Q\left(b\sqrt{\gamma }\right)$ be the BER of a BPSK system over an AWGN channel with two-sided noise power spectral density N₀/2. The parameter γ is a function of bit energy and noise power spectral density. A system with two independent and identical AWGN channels with noise power spectral density N₀/2 is shown in the figure. The BPSK demodulator receives the sum of outputs of both channels.



If the BER of this system is Q(𝑏√𝛾), then the value of b is _______