Week 7 Filters and Data Converters
Basic building blocks of Electronics System: Data Converteres
### Key Points on Analog to Digital Converters (ADCs)
1. **Types of ADCs**:
- **Flash ADC**:
- Uses multiple comparators to compare input voltage with reference voltages.
- Fast conversion time but requires a large number of comparators.
- For an n-bit code, \(2^n - 1\) comparators are needed.
- **Dual Slope ADC**:
- Commonly used in digital voltmeters.
- Involves integrating the input signal and then discharging it.
- Count duration is proportional to the input voltage.
- **Successive Approximation ADC**:
- Uses a Digital to Analog Converter (DAC) and a comparator.
- Bits are enabled one at a time, starting with the most significant bit (MSB).
- The output indicates if the input signal is greater or less than the DAC output.
- **Sigma-Delta ADC**:
- Based on delta modulation, quantizes the difference between successive samples.
- Outputs a single-bit stream indicating the amplitude of the input signal.
, - Incorporates feedback to maintain signal integrity.
2. **Flash ADC Operation**:
- Compares input voltage with reference voltages.
- Outputs from comparators go to a priority encoder to generate a binary output.
- Quick conversion but limited by the number of comparators.
3. **Dual Slope ADC Operation**:
- Integrates the input signal, then discharges while counting.
- The time taken to discharge correlates to the input voltage.
4. **Successive Approximation ADC Operation**:
- Uses a SAR (Successive Approximation Register).
- Compares input voltage to the DAC output and adjusts bits accordingly.
- Efficient for moderate-speed applications.
5. **Sigma-Delta ADC Operation**:
- Involves an integrator, quantizer, and feedback loop.
- Counts the number of 1s in the output stream to determine amplitude.
6. **Practical Applications**:
- Understanding how to integrate ADCs and DACs in electronic systems is crucial.
- Important for signal conditioning, interfacing with sensors, and data display.
7. **Final Notes**:
- Familiarize yourself with block diagrams and circuit designs.
- Practice using ADCs and DACs in various applications for a deeper understanding.
Feel free to revisit these concepts or ask any questions if you need further clarification!
Basic building blocks of Electronics System: Data
Converteres (contd.. )
Sure! Here are the key points from the module on digital-to-analog converters (DACs) and
signal conditioning circuits:
### Previous Module Recap
- Reviewed operational amplifier applications: inverting, non-inverting, unity follower, summing,
and differential amplifiers.
- Discussed filters: low pass, high pass, band pass, and band reject.
- Explored analog-to-digital converters (ADCs).
### Digital-to-Analog Converters (DACs)
1. **Basic Structure**:
, - Comprises digital input, reference voltage, and output in the analog domain.
- Early DACs were built from vacuum tubes; modern versions use op-amps and resistors.
2. **Types of DACs**:
- **Binary Weighted DAC**:
- Uses weighted resistors (R, 2R, 4R) in a summing amplifier configuration.
- Output voltage (V_out) is calculated based on the contributions of each bit (most to least
significant).
- Advantages: Simple construction, fast conversion.
- Limitations: Requires precise resistors, not scalable for high bit numbers.
- **R-2R Ladder DAC**:
- Uses only two resistor values (R and 2R).
- Easier to construct with fewer precision requirements.
- Slower conversion compared to binary weighted DAC.
### Signal Conditioning Circuits
- **Purpose**: Convert sensor outputs (like resistance changes) to a usable voltage for further
processing.
- **Wheatstone Bridge**:
- Effective for resistive sensors, compensates for resistance changes.
- Consists of four resistors; the output voltage is proportional to changes in the sensor
resistance.
- Drawbacks include offset voltage and the need for temperature compensation.
### Circuit Configurations
1. **Constant Voltage Source**:
- Output voltage varies based on resistance changes; different configurations yield different
linearity errors.
2. **Constant Current Source**:
- Similar output equations, but the relationship changes with current-driven circuits.
- Selection of current influences measurement accuracy and response.
### Conclusion
- The importance of understanding DACs and signal conditioning circuits for effective sensor
interfacing and system design.
Feel free to dive deeper into any specific section or concept!
Basic building blocks of Electronics System: Signal
Conditioning Circuits
Basic building blocks of Electronics System: Data Converteres
### Key Points on Analog to Digital Converters (ADCs)
1. **Types of ADCs**:
- **Flash ADC**:
- Uses multiple comparators to compare input voltage with reference voltages.
- Fast conversion time but requires a large number of comparators.
- For an n-bit code, \(2^n - 1\) comparators are needed.
- **Dual Slope ADC**:
- Commonly used in digital voltmeters.
- Involves integrating the input signal and then discharging it.
- Count duration is proportional to the input voltage.
- **Successive Approximation ADC**:
- Uses a Digital to Analog Converter (DAC) and a comparator.
- Bits are enabled one at a time, starting with the most significant bit (MSB).
- The output indicates if the input signal is greater or less than the DAC output.
- **Sigma-Delta ADC**:
- Based on delta modulation, quantizes the difference between successive samples.
- Outputs a single-bit stream indicating the amplitude of the input signal.
, - Incorporates feedback to maintain signal integrity.
2. **Flash ADC Operation**:
- Compares input voltage with reference voltages.
- Outputs from comparators go to a priority encoder to generate a binary output.
- Quick conversion but limited by the number of comparators.
3. **Dual Slope ADC Operation**:
- Integrates the input signal, then discharges while counting.
- The time taken to discharge correlates to the input voltage.
4. **Successive Approximation ADC Operation**:
- Uses a SAR (Successive Approximation Register).
- Compares input voltage to the DAC output and adjusts bits accordingly.
- Efficient for moderate-speed applications.
5. **Sigma-Delta ADC Operation**:
- Involves an integrator, quantizer, and feedback loop.
- Counts the number of 1s in the output stream to determine amplitude.
6. **Practical Applications**:
- Understanding how to integrate ADCs and DACs in electronic systems is crucial.
- Important for signal conditioning, interfacing with sensors, and data display.
7. **Final Notes**:
- Familiarize yourself with block diagrams and circuit designs.
- Practice using ADCs and DACs in various applications for a deeper understanding.
Feel free to revisit these concepts or ask any questions if you need further clarification!
Basic building blocks of Electronics System: Data
Converteres (contd.. )
Sure! Here are the key points from the module on digital-to-analog converters (DACs) and
signal conditioning circuits:
### Previous Module Recap
- Reviewed operational amplifier applications: inverting, non-inverting, unity follower, summing,
and differential amplifiers.
- Discussed filters: low pass, high pass, band pass, and band reject.
- Explored analog-to-digital converters (ADCs).
### Digital-to-Analog Converters (DACs)
1. **Basic Structure**:
, - Comprises digital input, reference voltage, and output in the analog domain.
- Early DACs were built from vacuum tubes; modern versions use op-amps and resistors.
2. **Types of DACs**:
- **Binary Weighted DAC**:
- Uses weighted resistors (R, 2R, 4R) in a summing amplifier configuration.
- Output voltage (V_out) is calculated based on the contributions of each bit (most to least
significant).
- Advantages: Simple construction, fast conversion.
- Limitations: Requires precise resistors, not scalable for high bit numbers.
- **R-2R Ladder DAC**:
- Uses only two resistor values (R and 2R).
- Easier to construct with fewer precision requirements.
- Slower conversion compared to binary weighted DAC.
### Signal Conditioning Circuits
- **Purpose**: Convert sensor outputs (like resistance changes) to a usable voltage for further
processing.
- **Wheatstone Bridge**:
- Effective for resistive sensors, compensates for resistance changes.
- Consists of four resistors; the output voltage is proportional to changes in the sensor
resistance.
- Drawbacks include offset voltage and the need for temperature compensation.
### Circuit Configurations
1. **Constant Voltage Source**:
- Output voltage varies based on resistance changes; different configurations yield different
linearity errors.
2. **Constant Current Source**:
- Similar output equations, but the relationship changes with current-driven circuits.
- Selection of current influences measurement accuracy and response.
### Conclusion
- The importance of understanding DACs and signal conditioning circuits for effective sensor
interfacing and system design.
Feel free to dive deeper into any specific section or concept!
Basic building blocks of Electronics System: Signal
Conditioning Circuits
