1 (440)

Prévia do material em texto

Step 1 of 3 8.061E Refer to the Figure 8.51 from the text book. Redraw the linear feedback shift-register counter with odd parity circuit in Figure 8-51 to change the odd parity circuit to even parity circuit as shown in Figure 1. The figure below shows the effect of physically changing the dd-parity to even-parity circuit inverting register connect to outputs CLOCK CLK (see table) PR OA XN-2 XN-3 X2 X1 XD From Exercise we know that even number of shift-register ourputs are connected to the parity circuit, and we also know that complementing two inputs of XOR gate does not change its output. we can redraw the logic diagram below. shill register connect to Figure 1 Step 2 of 3 Complementing the even number of inputs of the XOR gate does not change the output. Redraw the Figure 1 as shown in Figure 2. From Exercise we know that an even number of shift-register outputs are connected to the parity and we also know that complementing two inputs XOR gate does not change its output. Therefore. we can the logic diagram shown below. register connect to outputs CLOCK CLK table) RESET_L PR SERIN XN-1 XN-2 XN-3 X2 X1 or XD oz Figure 2 Step 3 of 3 Write the expression for the feedback equation of the linear feedback shift-register counter for selected values of n as follows: n Feedback Equation 2 4 6 8 12 16 Therefore, from the expression for the feedback equation of the linear feedback shift-register LFSR counter for selected values of n the bit X0 appears on the right side of all the equations. Hence, proved that the bit X0 appears on the right side of all the equations of LFSR counter.