Shift Register : All About Shift Register

A register that is used to store binary information is known as memory register. A register capable of shifting binary information either to the right or to the left is called a shift register. The shift register permits the stored data to move from a particular comated in such a way that the bits of binary number are entered into the shift register, shifted from one position to another and finally shifted out. There are two methods of shifting the data viz., 1) Serial shifting and 2) parallel shifting. The serial shifting method shifts one bit at a time for each clock pulse in a serial fashion , beginning with either MSB or the LSB. For example, a 4-bit register requires four clock pulses to shift a bit from the input to the output. In parallel shifting operation all the data get shifted simultaneously during a single clock pulse. Hence, the parallel shifting method is much faster than the serial shifting method. These two methods can be used to shift data into a register and out of register. Shift registers are classifie into the following four types based no how binary information is entered or siftied out. 1)Serial in serial out 2)serial in parallel out 3)parallel in serial out 4)parallel in parallel out Registers can be designed using discrete flip flops. An n bit shift register consists of o flip flops and the required gates to control the shift operation. Registers are also avialable as MSI devices. Shift register are used in digital systems for the temporay storage of information data manipulation and transferring. In addition, they are used in counting circuits, such as simple counters, variable modulo counters, up/down counters and increment counters.

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