PIRA32 Microcontroller
m32.pdf - page 8
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3.7
Digital-to-Analog converter
The Microcontroller uses parallel 8-bit D/A converter with over-sampling technique. Digital data provided on DA
pins can be directly formed into final analogue RDS output signal using low-cost resistor network.
Figure 4.3 shows accurate 8-bit DAC using R/2R resistor network.
It’s a binary weighted DAC that creates each
value with a repeating structure of 2 resistor values, R and R times two. This is an optimal DAC for this device.
The resistor value tolerance must not exceed 2 %.
Figure 4.3
- 8-bit D/A converter R/2R network
Figure 4.4
– Output RDS signal on oscilloscope (horizontal: 200 µs/div, vertical: 500 mV/div).
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