对加法器ccs进位链的改进.pdf

( ) , 42 , 3 , 2006 5 Acta Scientiarum Naturalium Universitatis Pekinensis, Vol. 42, No. 3 ( Ma 2006) 对加法器CCS 进位链的改进 2) 吴 珂 甘学温 赵宝瑛 2) ( , , 100871, wuke@ ime. pku. edu. cn) CCS , CCS SPICE , 4-bit 34139% , 4 33195% ; ; CCS; CSS; + TP 33212 1 An Improvement on Carry Chain of Conditional Carry Selection 2) WUKe GAN Xuewen ZHAO Baoying ( Institute of Microelectronics, Sc ool of Electronics Engineering and Computer Science , Peking University , Beji ing, 100871, 2) wuke@ ime. pku. edu. cn) Abstract An improved conditional carr selection ( CCS) circuit is proposed in this paper. The new circuit is compared with the conventional conditional carr selection structure for a 4-bit adder. The two circuits were simulated b SPICE under the same condition and the results show that the propagation time of carr and sum ( C and S ) of 4-bit adder are reduced 34139% and 3 3 33195% , respectivel . Key words carr chain; adder; CCS; CSS; propagation time 0 CCS CSS , [ 7] , DPL , , , ALU , 1 ( CCS) , , [ 1] , Manchester ; , [ 2]