Two non-inverting amplifiers, one having a unity gain and other having a gain of twenty, are made using identical operational gain amplifier, the amplifier with gain twenty has

In figure, all transistors are identical and have a high value of beta. The voltage VDC is equal to ______.

A binary source has symbol probabilities 0.8 and 0.2. If extension coding (blocks of 4 symbols) is used, the lower and upper bounds on the average code word length are :
(a)lower___________.
(b) higher_________.

For the signal constellation shown in the figure, the type of modulation is ________.