Correlator is a coherent system of signal reception.158 0 objstream (a variation of FSK) IS-54: π/4-DQPSK modulation is used (a variation of PSK) J.4 The modulation process making the transmission possible involves switching (keying) the amplitude, frequency, or phase of a sinusoidal carrier in accordance with the incoming data. Amplitude shift keying is also known as on-off keying.Ģ9. Probability of error in DPSK in less than BPSK.Ģ8. In BFSK, no synchronous carrier is needed at the receiver. In DPSK, no synchronous carrier is needed at the receiver. Select the correct answer from the codes given below:
It may produce phase error if synchronization is improper.It maximizes the SNR at the detection instant.Its impulse response depends on the signal shape.Which of the following statements about the matched filter in a communication receiver are correct? The value of N 0 will determine which of the two constellations has a lower probability of symbol error.Īnswer: Probability of symbol error for constellation 1 is lower.
Probability of symbol error is equal for both the constellations.Probability of symbol error for constellation 1 is higher.Probability of symbol error for constellation 1 is lower.If the constellations of above examples are used for digital communication over AWGN channel, then which of the following statements is true? The ratio of the average energy of constellation 1 to the average energy of constellation 2 is Let N 0/2 denote the power spectral density of white Gaussian noise. Assume that the four symbols in both the constellations are equiprobable. It is given that ϕ1 and ϕ2 constitute an orthonormal basis for the two constellations. Two 4-ary signal constellations are shown. Choose the correct one from among the alternatives A, B, C, D after matchling an item from Group 1 with the most appropriate item in Group 2. Assuming that the bandwidth of the above rectangular pulse is 10 kHz, B1 are and B2 Let B1 and 82 be the bandwidth requirements of BPSK and QPSK respectively. The source output is transmitted using two modulation schemes, namely binary PSK and quadrature PSK. The binary symbols are represented as shown in the figure. A source produces binary data at the rate of 10 kbps.
If S represents the carrier synchronization at the receiver and ρ represents the bandwidth efficiency, then the correct statement for the coherent binary PSK is For a given probability of error, binary coherent FSK is inferior to binary coherent PSK by For a bit-rate of 8 kbps, the best possible values of the transmitted frequencies in a coherent binary FSK system are For a given data rate, the bandwidth β p of a BPSK signal and the bandwidth βo of the OOK signal are related as To reduced the transmission bandwidth to 2400 Hz, the modulation scheme to be adopted should beĪnswer: 16-ary quadrature amplitude modulation If a binary PSK modulation is used for transmission, the required minimum bandwidth is 9600 Hz. These waveforms will be orthogonal for a bit interval of In a digital communication system employing FSK, the 0 and 1 bits are represented by sine waves of 10 kHz and 25 kHz respectively. The peak amplitude of the filter output is Binary data is transmitted using BPSK signalling scheme with S_\right. The output S/N ratio of a matched filter, fed at its input by a rectangular pulse of amplitude A and duration T, is given as (assume τ as noise power spectral density) Which of the following gives minimum probability of error? Which of the following gives maximum probability of error?
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