this presentation includes information and circuit diagram for atmega16 based function generator using c-code

2. WAVE GENERATOR
(AVR DDS Signal Generator)

3. Table of Contents
Abstract
1.0 Introduction
2.0 Components
3.0 Working of circuit
4.0 Firmware
5.0 Program Structure
6.0 Simulation
7.0 Veroboard implementation
8.0 Testing
9.0 Learning Outcomes
10.0 Conclusion

4. Introduction
The project assigned as mentioned earlier was the development of
the Wave Generator with the specifications that it can output four
kinds of waves (Sine, Triangular, Square, Sawtooth) within the
user dependent frequency range of 100-10kHz.

5. Working
It uses R-2R resistor ladder for digital to analog
(DAC) converter. It is an electrical circuit made
from repeating units of resistors.
An R–2R Ladder is a simple and inexpensive way
to perform digital-to-analog conversion, using
repetitive arrangements of precise resistor
networks in a ladder-like configuration.
Resistors used with the more significant bits (b-bit
significance is used here) must be proportionally
more accurate than those used with the less
significant bits.

6. Generator has three outputs:
Universal DAC output through R-2R ladder
PWM
Impulse (SQ)
Universal output (OUT) is a signal output from DAC. This
output is to form various signals like sawtooth, sine, square,
triangle.
PWM channel is used to form for PWM signal output –
directly from timer.

7. Disadvantage: for an n-bit ADC, the number of
resistors grows exponentially, as 2 n {displaystyle
2^{n}} resistors are required, while the R–2R
resistor ladder only increases linearly with the
number of bits, as it needs only 2 n {displaystyle
2n} resistors.
Advantage: higher impedance values can be reached
using the same number of components.
In this schematic R=10kohm. By using 8 bits and 5V
step value is about 18.5mV. This is enough for
getting average quality signals.

8. Block diagram

9. Circuit Diagram

10. Simulation

11. Some Outputs

12. Conclusion
Concluding with all the required information of the
components in use, development of circuit and its
simulation on software. Achieving the desired output
and observing it to manipulate the results held major
importance in clearing the concepts regarding the
concerned topic.