I have a topic that relates to "Digital Systems" in the topic "Introduction to Computer Organization and Architecture."
Then I stumbled upon this topic, "Coding Complementary"
There are three parts that are as follows:
i) Excess 3 (I understand this part because it requires adding 3 to the BCD)
ii) 84-2-1 (I do not understand)
iii) 2 * 421 (I do not understand)
I hope someone can explain how parts ii and iii work.
Thank you so much.
I think this part of Morris Mano’s Digital Design will answer your question:
BCD 2421 . , 1s .
Four Different Binary Codes for the Decimal Digits _____________________________________________________________ Decimal BCD 2421 Excess‐3 8, 4, -2, -1 Digit 8421 _____________________________________________________________ 0 0000 0000 0011 0000 1 0001 0001 0100 0111 2 0010 0010 0101 0110 3 0011 0011 0110 0101 4 0100 0100 0111 0100 5 0101 1011 1000 1011 6 0110 1100 1001 1010 7 0111 1101 1010 1001 8 1000 1110 1011 1000 9 1001 1111 1100 1111 _____________________________________________________________ 1010 0101 0000 0001 Unused 1011 0110 0001 0010 bit 1100 0111 0010 0011 combi- 1101 1000 1101 1100 nations 1110 1001 1110 1101 1111 1010 1111 1110
2421, -3 84-2-1 . , 9s- 1s 0s 0s 1s ( ). , 395 -3- 0110 1100 1000. 9s- 604 1001 0011 0111, ( 1- ).
- -
, 84-2-1 2421 " ", " " ( , 9), .. 84-2-1 (8 + 4-2-1 = 9) 2421 (2 + 4 + 2 + 1 = 9)., , , : 9 ( 9 )
, 84-2-1.
0 = 0000 ( 84-2-1) (9 0 = 9), 9 ( 84-2-1), 1111. , 0 9-, .. 9, -.
:
1 = 0111 ( 84-2-1) (9 1 = 8), (84-2-1) 8, 1000, , .
, 2421, , , , 9- .