Slide for student who want to take EASA part66 exam Other note you can get at http://part66.blogspot.com

1. 5.3 DATA CONVERSION
www.part66.blogspot.com

2. SYLLABUS
5.3 Data Conversion L1
• Analogue Data, Digital Data;
• Operation and application of analogue to
digital, and digital to analogue
converters, inputs and outputs, limitations of
various types

3. DEFINING ANALOGUE AND DIGITAL
DATA
• Analogue
– Most real life data are analogue
– It can have variable value and can fit into any
readings.
• E.g students’ height , 165cm, 155cn, 177cm .. Etc
• Discrete
– Digital signal in any of the given state, example
either 0 or 1.
– It cannot have any reading in between.

4. EXAMPLES OF DATA CONVERTION
• Digital to Analogue
– Like CD data to speakers inputs
• Analogue to Digital
– Microphone outputs to digital for storage in CD.

5. Accuracy and Conversion
• In the analogue to digital converter, there are
two important features:
– Accuracy – measure of how close the figure to
true value. Example 1% accuracy means, for
100v, the reading can range between 99v to 101v.
– Resolution – respond to the changes in value. A
resolution of 100mv, will enable to digital output
to 0.1 volt

6. ANALOGUE TO DIGITAL
+VE
8
7 VREF
ANALOGUE SIGNAL
6
5
4 + VOUT
3 VIN
2
1
0 0 0 0 1 1 1 1
As many as the bits
0 0 1 1 0 0 1 1 3 BIT
WORD
0 1 0 1 0 1 0 1
DIGITAL SIGNAL
• Thus the more bits available the greater the • The output of the comparator will be logic
resolution for a given range of analogue “0” when the reference voltage is greater
signal input. It can be seen from the above than the analogue input, It will be logic “1”
that an ADC using an n-bit word would have when the analogue voltage is greater than
a resolution of one part in 2n the reference voltage.

7. ANALOGUE TO DIGITAL

8. DIGITAL TO ANALOGUE CONVERTER
• Note that the discrete
16 nature of the graph.
• The Digital Signal need
ANALOGUE O/P SIGNAL
14
12
the circuit to convert to
10
analogue.
8
6
4
2
0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1
0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
DIGITAL I/P SIGNAL

9. DAC Converter
•
MSB R
4
B
2R
I
T V OUT
W 4R
O
R
D
LSB 8R