Digital to Analog Converter by LDCE students

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Digital to Analog Converter by LDCE students

  1. 1. L. D. COLLEGE OF ENGINNERING AHMEDABAD-380015 GUIDED BY: PROF. P.P. PRAJAPATI ASSISTANT PROFESSOR, DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING. L. D. COLLEGE OF ENGINEERING, AHMEDABAD. PREPARED BY: MITUL LAKHANI DHAVAL SONANI VISHAL GONADALIYA
  2. 2. WHAT IS DAC??  In electronics, a digital- to- analog converter (DAC or D-to-A) is a device that converts a digital (usually binary) code to an analog signal ( current, voltage, or electric charge). An analog digital converter (ADC) performs the reverse operation. Signals are easily stored and transmitted in digital form, but a DAC is needed for the signal to be recognized by human senses or other non-digital systems.
  3. 3. GENERAL USE OF DAC.  A common use of digital-to- analog converters is generation of audio signals from digital information in music player.  Digital video signals are converted to analog in televisions and cell phones to display colors and shades.  Digital-to- analog conversion can degrade a signal, so conversion details are normally chosen so that the errors are negligible.
  4. 4. DAC USING MICROCONTROLLER  The digital-to-analog converter (DAC) is a device widely used to convert digital pulses to analog signals.  Recall from your digital electronics book the two methods of creating a DAC: Binary weighted and R/2R ladder.  The vast majority of integrated circuit DACs, including the MC1408 (DAC0808) used in this section, uses the R/2R method since it can achieve a much higher degree of precision.
  5. 5. STEP BY STEP PROCEDURE FOR INTERFACING MCU-DAC COMPONENTS REQUIRED  MCU (AT89C51)  DAC0808/MC1408  Resistors (10k,8.2k).  Capacitors(33pF,10uF).  Op-amp.  Oscilloscope.  Power Supply.
  6. 6. STEP BY STEP PROCEDURE FOR INTERFACING MCU-DAC ALGORITHAM:
  7. 7. STEP BY STEP PROCEDURE FOR INTERFACING MCU-DAC CIRCUIT DIAGRAM:
  8. 8. STEP BY STEP PROCEDURE FOR INTERFACING MCU-DAC  Procedure to generate Sine wave:  To generate a sine wave, first a table is designed whose values represent the amplitude of the sine of the angles between 0 and 360 degrees. The value of the sine function varies from -1.0 to +1.0  To generate the sine wave the output of DAC is assumed to be 10V. Full scale output of the DAC is achieved when all the data inputs of the DAC are high. Therefore to achieve the full-scale 10V output, we use following equation. Vout = 5V + (5*sinø)
  9. 9. DATA TABLE FOR SINE WAVE GENERATION
  10. 10. FLOWCHART FOR OUR PROGRAM START INITIALISE VARIABLE USE DPTR AS A POINTER TO POINT TO THE LOOK UP TABLE DATA ACCESSING USING INDEXED ADDRESSING MODE VALUE IS SENT TO THE PORT1 AND INCREMENT DPTR DECREMENT COUNTER=0?? END NO YES
  11. 11. ASSEMBLY LANGUAGE PROGRAM START:MOV DPTR,#TABLE MOV R1,#13 CLR A LOOP: MOVC A,@A+DPTR MOV P1,A INC DPTR DJNZ R1,LOOP SJMP START TABLE: ORG 200H DB 128,192,238,255,238,192,128,64,17,0,17,64,128
  12. 12. IMAGE OF SINEWAVE WHICH WE GET ON OSCILLOSCOPE….
  13. 13. QUERY????

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