余3码 到 BCD 转换器
余3码 到 BCD 转换器是数字电子中的一种代码转换器,用于将 XS-3 代码转换为等效的二进制编码十进制。
因此,XS-3 到 BCD 代码转换器接受 XS-3 格式的数字代码并生成等效的 BCD 格式的数字代码。
XS-3 到 BCD 代码转换器的真值表如下所示 −
余3码 代码 | BCD 代码 | ||||||
---|---|---|---|---|---|---|---|
X3 | X2 | X1 | X0 | B3 | B2 | B1 | B0 |
0 | 0 | 0 | 0 | X | X | X | X |
0 | 0 | 0 | 1 | X | X | X | X |
0 | 0 | 1 | 0 | X | X | X | X |
0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 |
0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 |
0 | 1 | 0 | 1 | 0 | 0 | 1 | 0 |
0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 |
0 | 1 | 1 | 1 | 0 | 1 | 0 | 0 |
1 | 0 | 0 | 0 | 0 | 1 | 0 | 1 |
1 | 0 | 0 | 1 | 0 | 1 | 1 | 0 |
1 | 0 | 1 | 0 | 0 | 1 | 1 | 1 |
1 | 0 | 1 | 1 | 1 | 0 | 0 | 0 |
1 | 1 | 0 | 0 | 1 | 0 | 0 | 1 |
1 | 1 | 0 | 1 | X | X | X | X |
1 | 1 | 1 | 0 | X | X | X | X |
1 | 1 | 1 | 1 | X | X | X | X |
Now, we will simplify this truth table using K-map method to obtain the Boolean expression for the output bits.
K-Map for BCD Bit B0
The following figure shows the K-map simplification for the BCD bit B0.

This K-map gives the following Boolean expression,
$$\mathrm{B_{0} \: = \: \overline{X_{0}}}$$
K-Map for BCD Bit B1
The following figure shows the K-map simplification for the BCD bit B1.

This K-map gives the following Boolean expression,
$$\mathrm{B_{1} \: = \: \overline{X_{1}} \: X_{0} \: + \: X_{1} \: X_{0}}$$
K-Map for BCD Bit B2
The K-map simplification for the BCD bit B2 is shown below −

The simplification of this K-map gives the following Boolean expression,
$$\mathrm{B_{2} \: = \: \overline{X_{2}} \: \overline{X_{1}} \: + \: \overline{X_{2}} \: \overline{X_{0}} \: + \: X_{2} \: X_{1} \: X_{0}}$$
K-Map for BCD Bit B3
The K-map simplification for the BCD bit B3 is shown in the following figure −

By simplifying this K-map, we obtain the following Boolean expression,
$$\mathrm{B_{3} \: = \: X_{3} \: X_{2} \: + \: X_{3} \: X_{1} \: X_{0}}$$
We can use these Boolean expressions to implement the digital logic circuit to perform the XS-3 to BCD conversion.
The logic circuit diagram to convert an XS-3 code into equivalent BCD code i.e., Excess-3 to BCD converter is shown in the following figure −

This is all about some commonly used digital code converters used in various digital electronic applications.