VIVA QUESTIONSADVANCED COMMUNICATION LAB1.Define Dirac comb or ideal sampling function.2.State sampling theorem.3.What is aliasing orfold over?4.What is meant by PCM?5.Define quantizing process.6.What is meant by idle channel noise?7.Define delta modulation8.Name the types of uniform quantizer.9.What is the need for speech coding at low bit rates?10.What is PAM?11.Define modulation rate.12.State NRZ unipolar format13.State Manchester format.14.What is Inter symbol interference?15.Which criterion makes ISI Zero?16.What is matched filter receiver?17.What is maximum likelihood detector?18.Define antipodal signals.19.Give the two basic operation of DPSK transmitter20.Define deviation ratio in MSK21.What are the three broad types of synchronization?22.What are the disadvantages of closed loop bit synchronization?23.Define code efficiency24.Define pseudo-noise (PN) sequence.25.What does the term catastrophic cyclic code represent?26.Define a random binary sequence.27.Give the correlation property of random binary sequence.28.What is called processing gain?29.What is called jamming effect?30.What is Anti jamming?31.What are the three codes used for the anti jamming application?32.What is called frequency hop spread spectrum?33.What are the two function of fast frequency hopping?34. What are the features of code Division multiple Accesses?35.What is called multipath Interference?36.What is the advantage of a spread spectrum technique?37.What is called frequency hop spread spectrum?38.BPFSK is more efficient than BFSK in presence of noise. Why?39.What is inter symbol interference?40.What is raised cosine pulse?41.Compare the bandwidth efficiency of the M-ary FSK and M-ary PSK modulation schemes

42.. If x(t) = cos (2pt / T) sin (4 pt / T) is to be sampled, what is the maximum sampling interval?43.A PCM system uses a uniform Quantizer followed by a 7-bit encoder. The rate of system is 50Mbits\second. Determine message bandwidth for system to operate satisfactorily44.Which modulation technique has best utilization of bandwidth?45.In which modulation scheme probability is maximum46.In which modulation scheme probability is minimum47.What is Nyquist rate?48.What is advantage of digital communication over analog communication?49.Which are the channels used for digital communication?50.Which kind of multiplexing used in digital communication?51.Define Aperture effect. How it can be avoided52.Why is Sample & Hold circuit used?53.An Analog signal is given asX(t) = 3cos 50t + 10 sin 300 t + cos 100tCalculate Nyquist rate54.The spectrum of a signal g(t) has bandwidth 0.8KHZ and centered around10 KHZ. Find Nyquist Rate55.What isrequirement for Transmission Bandwidth?56.Difference between Coherent and Non-coherent detection57.Signal constellation diagram of all modulation schemes58.A PCM system uses a uniform quantizer followed by a 7 bit encoder, with bit rate 50Mbps.What is the message bandwidth for system to operate satisfactorily?59.Properties of Matched filter?60.Difference between CDMA & TDMA61.What is Pulse code modulation (PCM)?62.How the performance of a PCM is corrupted?63.What are the two types of Spread spectrum technique?64.We need to send 3 bits at a time at a bit rate of3Mbps.The carrier frequency is 10MHz.Calculate No of levels and Bandwidth65.What is a Constellation Diagram?66.Which modulation is a combination of other 2 schemes?67.Name twoprinciples by which spread spectrum achieves its goal68.Which of the 3 multiplexing techniques is common for fiber optic links69.What is the minimum number of bits in a PN sequence if we use FHSS with a channel bandwidth of 5kHz and Bss=120kHz?70.Which theorem gives Maximum Data Rate of the channel?