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Digital to Analog Converters

Digital to Analog Converters. Digital to Analog Conversion. Digital data representing an analog signal (for instance an MP3 file) sampled at a (usually) fixed time interval is fed to a Digital to Analog Converter

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Digital to Analog Converters

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  1. Digital to Analog Converters Jordan Nash - Microprocessor Course

  2. Digital to Analog Conversion Digital data representing an analog signal (for instance an MP3 file) sampled at a (usually) fixed time interval is fed to a Digital to Analog Converter The output is an analog waveform which is an approximation to the original analog signal Jordan Nash - Microprocessor Course

  3. Recall: The 741 Op.Amp • Summing Amplifier Exercise : Show that Vout = - (V1+V2+V3) Jordan Nash - Microprocessor Course

  4. The 741 Op.Amp • R-2R Network to convert digital to analog Jordan Nash - Microprocessor Course

  5. Operation II The basic operational idea of the DAC we will be using is simply to have a series of switches which control a resistor network Depending on which bits are set, the output voltage changes Jordan Nash - Microprocessor Course

  6. The TLC7524 DAC For your analog signal generator you will be using an 8-bit DAC to convert an 8-bit data stream , from the ATmega128 ports, to analog signals of given frequency, amplitude and offset Jordan Nash - Microprocessor Course

  7. Write Cycles of the TLC7524 The DAC has internal registers to store the input Data (1 Byte) and signals which control the write operation (CS*, WR*): Jordan Nash - Microprocessor Course

  8. DAC Operation The output signal will need to be fed into an external op-amp Data should be put on the data bus using one of the ATMEL PORTs CS* can be held low Jordan Nash - Microprocessor Course

  9. Schematic You can write numbers to the DAC in a similar way as with the 3-byte memory module using the ATmega128 Ports CS* : keep it enabled Jordan Nash - Microprocessor Course

  10. Task Plan • Design and construct a Signal Generator: • The ATmega128 should be used to design a signal generator. • The Amplitude, Frequency and Voltage offset should be subject to change under program control. • The signals should be produced using a DAC and an Operational Amplifier driven by one of the ATmega128 ports. • The generator should have a user interface. • The LCD should be used to display a menu and the given frequency amplitude and offset settings. • The Keyboard should be used for user input. Jordan Nash - Microprocessor Course

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