Question 4 (a) Explain how the convolutional codes work. [6 Marks] (b) Why an off-keying signal with waveform energy E has worse Signal-to-noise Ratio with respect a bipolar signal with the same energy for each waveform? [6 Marks] (c) For a binary convolutional code with k = 1 (the number of inputs) and n= 3 (the number of outputs), find the number of states if there are 4 registers used, also define the code rate of this code. [6 Marks] (d) Describe the how a Nyquist pulse will eliminate ISI errors in case of perfect time sampling. Sketch a Nyquist pulse. [7 Marks] Question 4 (a) Explain how the convolutional codes work. [6 Marks] (b) Why an off-keying signal with waveform energy E has worse Signal-to-noise Ratio with respect a bipolar signal with the same energy for each waveform? [6 Marks] (c) For a binary convolutional code with k = 1 (the number of inputs) and n= 3 (the number of outputs), find the number of states if there are 4 registers used, also define the code rate of this code. [6 Marks] (d) Describe the how a Nyquist pulse will eliminate ISI errors in case of perfect time sampling. Sketch a Nyquist pulse. [7 Marks]