Rainbow Electronics MAX1209 - Manual (Page 20)

MAX1209
12-Bit, 80Msps, 3.3V IF-Sampling ADC
20 ______________________________________________________________________________________
BINARY-TO-GRAY CODE CONVERSION
1) THE MOST SIGNIFICANT GRAY-CODE BIT IS THE SAME
AS THE MOST SIGNIFICANT BINARY BIT.
0 1 1 1 0 1 0 0 1 1 0 0 BINARY
GRAY CODE 0
2) SUBSEQUENT GRAY-CODE BITS ARE FOUND ACCORDING
TO THE FOLLOWING EQUATION:
D11 D7 D3 D0
GRAY X = BINARY X + BINARY X + 1
BIT POSITION
0 1 1 1 0 1 0 0 1 1 0 0 BINARY
GRAY CODE 0
D11 D7 D3 D0 BIT POSITION
GRAY 10 = BINARY 10 BINARY 11
GRAY 10 = 1 0
GRAY 10 = 1
1
3) REPEAT STEP 2 UNTIL COMPLETE:
0 1 1 1 0 1 0 0 1 1 0 0 BINARY
GRAY CODE 0
D11 D7 D3 D0 BIT POSITION
GRAY 9 = BINARY 9 BINARY 10
GRAY 9 = 1 1
GRAY 9 = 0
1 0
4) THE FINAL GRAY CODE CONVERSION IS:
0 1 1 1 0 1 0 0 1 1 0 0 BINARY
GRAY CODE 0
D11 D7 D3 D0 BIT POSITION
1 0 0 1 1 0 1 1 0 1 0
GRAY-TO-BINARY CODE CONVERSION
1) THE MOST SIGNIFICANT BINARY BIT IS THE SAME AS THE
MOST SIGNIFICANT GRAY-CODE BIT.
2) SUBSEQUENT BINARY BITS ARE FOUND ACCORDING TO
THE FOLLOWING EQUATION:
D11 D7 D3 D0
BINARY X = BINARY X+1
BIT POSITION
BINARY 10 = BINARY 11 GRAY 10
BINARY 10 = 0 1
BINARY 10 = 1
3) REPEAT STEP 2 UNTIL COMPLETE:
4) THE FINAL BINARY CONVERSION IS:
0 1 0 0 1 1 1 0 1 0 1 0
BINARY
GRAY CODE
D11 D7 D3 D0 BIT POSITION
0 BINARY
GRAY CODE 0 1 0 0 1 1 0 1 1 0 1 0
BINARY 9 = BINARY 10 GRAY 9
BINARY 9 = 1 0
BINARY 9 = 1
GRAY X
0 1 0 0 1 1 1 0 1 0 1 0
BINARY
GRAY CODE
0
D11 D7 D3 D0 BIT POSITION
1
0 1 0 0 1 1 1 0 1 0 1 0
BINARY
GRAY CODE
0
D11 D7 D3 D0 BIT POSITION
1 1
0 1 1 1 0 1 0 0 1 1 0 0
A B Y = A B
0 0
0 1
1 0
1 1
0
1
1
0
EXCLUSIVE OR TRUTH TABLE
WHERE IS THE EXCLUSIVE OR FUNCTION (SEE TRUTH
TABLE BELOW) AND X IS THE BIT POSITION: + WHERE IS THE EXCLUSIVE OR FUNCTION (SEE TRUTH
TABLE BELOW) AND X IS THE BIT POSITION:
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Figure 9. Binary-to-Gray and Gray-to-Binary Code Conversion