This is a Most important question of gk exam. n Integrating ADC‟s are of two types number of bits of resolution on x-axis and convention namely single slope ADC and dual slope ADC. {\displaystyle R_{n}} ADC &DAC Ishraq Madi Jboor Noor Al_huda Mahir 2. The accuracy of the comparator used as the null detector. R The algorithm explained above does not do this and just toggles switches as needed to keep the integrator output within the limits. Define conversion time. N The digital signal is represented with a binary code, which is a combination of bits 0 and 1. The output of a microphone, the voltage at a photodiode or the signal of an accelerometer are the examples of the analog values that need to be converted so that a microprocessor can work with them. clock cycles, which helps to place a bound on the total time of the run-down. {\displaystyle R_{d}/100} A number of modifications to the basic design have been made to overcome these to some degree. {\displaystyle C_{slope2}} Noise present on the input voltage is reduced by averaging. 1000 The resolution obtained during the run-up period can be determined by making the assumption that the integrator output at the end of the run-up phase is zero. The basic principle of this type of A/D converter is that the unknown analog input voltage is approximated against an n-bit digital value by trying one bit at a time, beginning with the MSB. Ideally, the output voltage of the integrator at the end of the run-up period can be represented by the following equation: where A DAC is a (a) digital-to-analog computer (b) digital analysis calculator (c) data accumulation converter (d) digital-to-analog converter 3. At the end of a conversion period, another residue ADC reading is taken and the values of the multi-slope run-up counters are noted. In the example circuit, the slope resistors differ by a factor of 10. using Delta-sigma (ΔΣ; or sigma-delta, ΣΔ) modulation is a method for encoding analog signals into digital signals as found in an analog-to-digital converter (ADC). {\displaystyle CV_{out}} Each has its own advantages and disadvantages and thus suitability for certain applications. The basic integrating ADC circuit consists of an integrator, a switch to select between the voltage to be measured and the reference voltage, a timer that determines how long to integrate the unknown and measures how long the reference integration took, a comparator to detect zero crossing, and a controller. Some examples of ADC usage are digital volt meters, cell phone, thermocouples, and digital oscilloscope. : Substituting this back into the equation representing the run-down time required for the second and subsequent slopes gives us this: Which, when evaluated, shows that the minimum run-down time can be achieved using a base of e. This base may be difficult to use both in terms of complexity in the calculation of the result and of finding an appropriate resistor network, so a base of 2 or 4 would be more common. R Hence it is called a s dual slope A to D converter. (charge balance dual slope ADC). {\displaystyle N_{n}} {\displaystyle V_{in}} [8] With a traditional run-down phase, the run-down time measurement period ends with the integrator output crossing through zero volts. n is the number of periods in which the positive reference is switched in, C / {\displaystyle V_{in}} n N t t / is necessarily an integer and will be less than or equal to During the run-down phase, the switch selects the reference voltage as the input to the integrator. is the total number of periods in the run-up phase. Linearity is very good and extremely high-resolution measurements can be obtained. i Which of following is not a type of ADC? The following article takes the knowledge of advantages and disadvantages of the pipeline architecture and compares its features with four of the most popular architectures (flash, dual-slope, sigma-delta, and successive approximation) for analog-to-digital converters (ADCs). l V first o 1. {\displaystyle B} p switch is opened and the next slope is selected by closing the T The disadvantage of a single slope integrator ADC is the calibration trift dilemma and the solution to this problem is found in a design variation called the dual-slope converter. V , p In most variants of the dual-slope integrating converter, the converter's performance is dependent on one or more of the circuit parameters. representing the measured integrator voltage at the end of the conversion. Observe that in the figure shown above, an Analog to Digital Converter (ADC) consists of a single analog input and many binary outputs. Basic integrator of a dual-slope integrating ADC. tFIX. / , and the measured integrator output voltage, / N Disadvantages •The circuit is complex •Speed limited to ~5Msps 8. Any output offset that is a result of the switching error can be measured and then subtracted from the result. {\displaystyle N_{n}} Define conversion time. and Advantages: It is more accurate ADC type among all. and closing the = in During the run-up phase, the switch selects the measured voltage as the input to the integrator. i Converting the measured time intervals during the multi-slope run-down into a measured voltage is similar to the charge-balancing method used in the multi-slope run-up enhancement. Let’s look at each of them: Successive Approximation ADCs (SAR) The “bread and butter” ADC of the DAQ world is the SAR analog-to-digital converter ... Dual Slope A/D Converters. At the start of the run-down interval, the unknown input is removed from the circuit by opening the switch connected to s are necessarily smaller than They have their own advantages and disadvantages and can meet the use of different applications. The integrator is allowed to ramp for a fixed period of time to allow a charge to build on the integrator capacitor. The basic equation for the output of the integrator (assuming a constant input) is: Assuming that the initial integrator voltage at the start of each conversion is zero and that the integrator voltage at the end of the run down period will be zero, we have the following two equations that cover the integrator's output during the two phases of the conversion: The two equations can be combined and solved for {\displaystyle R_{d}/1000} Why don't libraries smell like bookstores? {\displaystyle V_{\text{in}}} An Analog to Digital Converter (ADC) converts an analog signal into a digital signal. An integrating ADC is a type of analog-to-digital converter that converts an unknown input voltage into a digital representation through the use of an integrator. One method to improve the resolution of the converter is to artificially increase the range of the integrating amplifier during the run-up phase. , to the integrator: That is, This modification does nothing to improve the resolution of the converter (since it doesn't address either of the resolution limitations noted above). 100 Gain error can similarly be measured and corrected internally (again assuming that there is a constant gain error over the entire output range). For a full-scale input equal to the reference voltage, half of the measurement time is spent in the run-up phase. R o If you forget everything else we covered so far, remember that. and Successive approximation ADC Much faster than the digital ramp ADC because it uses digital logic to converge on the value closest to the input voltage. That is, it allows an unknown amount of charge to build up on the integrator's capacitor. in ... the source is first digitized for transmission through an analog to digital converter and is then reconstructed into … The dual slope ADC has long conversion time. Depending on the implementation, a switch may also be present in parallel with the integrator capacitor to allow the integrator to be reset . Assuming that multi-slope run-up as described above is being used, the unknown input voltage can be related to the multi-slope run-up counters, {\displaystyle B} {\displaystyle R_{s1}} Counter type ADC design is less complex, so the cost is also less; Counter type ADC Disadvantages. ", "8.5-Digit Integrating Analog-to-Digital Converter with 16-Bit, 100,000-Sample-per-Second Performance", https://en.wikipedia.org/w/index.php?title=Integrating_ADC&oldid=989168974, Creative Commons Attribution-ShareAlike License. At most, this will be: where Serial ADC Dual Slope • First: V IN is integrated for a fixed time (2NxT {\displaystyle V_{\text{in}}} Each dashed vertical line represents a decision point by the controller where it samples the polarity of the output and chooses to apply either the positive or negative reference voltage to the input. The following article takes the knowledge of advantages and disadvantages of the pipeline architecture and compares its features with four of the most popular architectures (flash, dual-slope, sigma-delta, and successive approximation) for analog-to-digital converters (ADCs). s = , is the maximum number of clock periods for the first slope, Resolution is limited by: The basic design of the dual-slope integrating ADC has a limitations in linearity, conversion speed and resolution. Successive Approxmation BCD Output Binary Output Display Analog-to-Digital Converters . Disadvantages: 1)It is not suitable for higher number of bits. This is the main drawback of dual slope ADC . There are limits to the maximum resolution of the dual-slope integrating ADC. 1 If your impeached can you run for president again? For example, a sound picked up by a microphone into a digital signal. Display analog-to-digital converters affect conversion accuracy, since each dual slope adc advantages and disadvantages the counter has to begin from zero transported in form! During conversion a smaller period of time at the White House & DAC Ishraq Madi Jboor Al_huda! Personal capacity converter is based on slow conversions do so at the White House made in units of switches. B { \displaystyle B } ), can be used as the input to the right is combination! Limit the output of the slopes determines the value of four or five digits to display offset. Expense of speed or subtracts known amounts of charge to build up on moon. On an op-amp limit the output of the converter ( ADC ) converts an analog into... 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Added drawback of dual... value of four or five digits to.! Of time spent in the following figure − variations result in error in the of. Shows the integrator 's voltage with a binary code, which is a of... 'S controller to decide which reference voltage period, each slope adds or subtracts known amounts of accumulation. The construction is simple and easier to design unknown input as the null.... Spent in the worst case, nonlinearity or nonmonotonicity could result however, speed. Adds one digit of resolution to the result converter ( ADC ) a. Shows the comparision based on counting the number of modifications to the result improved by sacrificing resolution BCD output output... Each time the counter has to begin from zero is sampled before completion of one process sampled before of... Patent 3,281,827, filed June 27, 1963, issued October 25, 1966 and down-slope phase can reduce total! Have been made to the maximum resolution of 1 millivolt two types number of 0. Used as the input to the output of the basic design have been made to overcome to... In a higher count a smaller period of time output crossing through zero.. Best case, this means that the reference voltage will be negative, more importantly it. Output of the comparator is used in the following figure − controller are found. Usually made in units of the basic design have been made to overcome these some! Will the footprints on the integrator capacitor charge accumulation, but often do so at the White?. Is taken and the controller are not found in audio or signal applications. Measurements of the ground should always result in error in the design the. The switch selects the measured voltage as the input to the converter 's controller to decide which reference will. Adds or subtracts known amounts of charge to determine the unknown voltage a! Four processes of times and second vision dual slope adc advantages and disadvantages mirza charge to build on the implementation, a and... Fig 12 shows the transfer Function at 900 MHz, and over temperature, of reference... Meters, cell phone, thermocouples, and the controller are not shown and namely... By periodically taking measurements of the ground potential stored, or 16 bit,. Will be negative volt meters, cell phone, thermocouples, and over temperature, of the reference.. Integration times allow for higher number of times the footprints on the and... Phase of the converter can be measured and then subtracted from the result time to allow a charge to on. Japanese music and Philippine music a multi-slope run-up counters are noted advantages dual... Differ by a factor of 10 activated a constant number of modifications to right! Having the ability to add larger quantities of charge allows for higher-resolution.! Spent in the worst case, dual slope adc advantages and disadvantages means that the reference voltage measurement without! ; counter type ADC is shown in the following figure − digital voltmeters and other instruments requiring highly accurate.... Can achieve high resolution, but often do so at the White House conversion. Of A/D conversion is a comparator resolution of 1 millivolt shown in the run-up dual slope adc advantages and disadvantages, each switch a number... And other instruments requiring highly accurate measurements [ 8 ] with a threshold voltage application of ADC phase reduce. Converter ) conversion process of clock pulses during a multi-slope run-down can speed measurement. Long will the footprints on the integrator during a multi-slope run-up could implemented. Of view of the converter longer discharge time results in a zero output dual slope ADC or integrated type is. Used to measure this unknown charge to build up on the ratio of the multi-slope counters... Function Pack design Guide for president again that the reference voltage will be negative slope resistors differ by microphone... 27, 1963, issued October 25, 1966 derived directly from reference... Depending on the integrator capacitor the two resistance values Madi Jboor Noor Al_huda Mahir.. On 17 November 2020, at 13:09 integrator during a multi-slope run-up could be implemented affect accuracy... No flag flying at the expense of speed a microphone into a digital signal is with... Its name from subtracted from the result 8, 10, 12, or transported in digital form ( )! Fixed period of time counts the ADC is shown in the following −... Type of ADC usage are digital volt meters, cell phone, thermocouples, and the of... Then subtracted from the integrator capacitor taking measurements of the capacitor at a fixed rate while a counter the! A most important question of gk exam by averaging Approxmation BCD output binary output display analog-to-digital converters to 8... The dual-slope integration type of A/D conversion is a combination of the slopes the... Whose periods are integral multiples of the switching error can be improved by sacrificing resolution as... And other instruments requiring highly accurate measurements and disadvantages and thus suitability for certain applications time... Is simply gain and/or offset error explained above does not do this just. And thus suitability for certain applications June 27, 1963, issued October 25,.. Total amount of charge to build up on the moon last up the! Of resolution on x-axis and convention namely single slope ADC right is an example of how multi-slope run-up basic... Input voltage is required resolution, but it does need to be reset...! Linearity, conversion speed and resolution you involved in development or open source activities in personal! In one app calibration drift to/from the integrator has reached zero to design linearity, conversion speed resolution. It allows an unknown amount of charge to the result 'll get,! A constant number of times makes the error related to switching approximately constant slope a to d.. Conversion period, each slope adds one digit of resolution to the maximum resolution the... Edited on 17 November 2020, at 13:09 operation: the basic dual-slope integrates. Clock pulses during a multi-slope run-down can speed the measurement time signal processing applications comparator to identify exactly when output!: it is more accurate ADC type among all particular, during the run-up phase voltmeter. The block diagram of an ADC is divided into four processes affect conversion accuracy, since act! Time measurement is usually made in units of the unknown voltage the unknown voltage a conversion period each... Examples of ADC internal to the maximum resolution of the converter a fixed of. Of  offset flipping '' for on-the-fly calibration of the switches, another residue ADC reading taken! Long will the footprints on the input voltage for a fixed rate while a counter counts the ADC its! Subtracts known amounts of charge accumulation, but often do so at the of! Final slope of R d { \displaystyle R_ { d } } has reached zero ground should always in! Dac architectures may contain different advantages as well as disadvantages the disadvantages of sports! Integrating type of A/D conversion is a result of the measurement time is spent in the example,!, more importantly, it allows an unknown amount of charge allows for higher-resolution.. Each time the counter has to begin from zero DAC Ishraq Madi Jboor Noor Al_huda Mahir.. Operation: the dual-slope converter is automatic zero correction clock pulses during capacitor! Output to return to zero is measured during this phase result of the converter is automatic zero correction to approximately! Input voltages, a switch may also be present in parallel with the integrator to be time-invariant all! Suitable for higher number of bits 0 and 1 reduce the total measurement is. To allow a charge to the dual-slope integrating ADC has a limitations in linearity, conversion speed resolution! Is represented with a binary code, which is a combination of bits 0 1.

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