A 4 bit shift register is initialized to value 1000 for (Q_{3}, Q_{2}, Q_{1}, Q_{0}). The D input is derived from Q_{0}, Q_{2} and Q_{3} through two XOR gates as shown in figure. The pattern 1000 will appear at

The PCM signal shown below uses amplitude level of +1 volt and -1 volt to represent binary symbol 0 and 1 respectively. Each code word consists of 4 bits. The sampled version of analog signal from which this PCM signal is derived is

Consider a situation where number of minterms with even number of 0's are same as number of minterms with odd number of 1's. Then minterms with even number of 0's and minterms with odd number of 1's are __________ to each other then number of variables is __________ .