Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [adc]

An ADC is an Analog to Digital Converter. This device converts analog signals into digital form. It is mainly used by digital circuitry to take analog measurements.

ADC stands for Analog to Digital Converter, and, as the name suggests, it's used for converting analog signals (world is analog) into bits, to allow digital processing.

The main parameters that characterize an ADC are the resolution (in bits) and the speed of conversion. That is also the main tradeoff between fast ADCs, made for real-time control of quick signals, and precision ADCs, used for accurate conversions like audio applications. In general, faster and higher resolution ADCs are higher power than slower and lower resolution ones.

Types of ADCs include

  • Flash: Damn Fast™, but use a lot of chip real estate, therefore only low resolution
  • Successive Approximation
  • Dual-Slope and Multi-Slope
  • Delta
  • Sigma-Delta

Further reading:
Walt Kester - The Data Conversion Handbook (ebook)

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Why are digital oscilloscopes still so expensive?

I'm a beginner in hobby electronics and I am wondering why digital oscilloscopes are still so expensive? In times of cheap GHz CPUs, USB 3, ADSL modems, DVB-S receivers, blu-ray players which all of them have remarkable clock frequencies/sampling…
MRalwasser
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How do I measure a negative voltage with a ADC?

I am working with a PIC micro-controller with inbuilt 10bit ADC and want to measure a voltage in the range of -1 to -3Volts. I thought of using an op-amp in the inverting mode to make voltage positive and then feed it to the adc of the…
Kevin Boyd
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What is the difference between an injected and regular STM32 ADC channel?

The STM32F1's reference manual describes "regular" and "injected" ADC channels but is not clear on the difference. What is the difference between the two types and when might you use one or the other?
joeforker
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Why do ADCs use 10 bit rather than 8 or 16?

Why is it that most ADCs, like the ones on the Arduino, give 10 bit resolution rather than 8 or 16 bit? It just seems wierd that they don't match standard data sizes, particularly on integrated ones.
Jesse Quisenberry
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How to Convert 0 to 10V analog signal to 0 to 2.5V for ADC input?

I have an analog signal which ranges between 0V and 10V. I want to linearly scale it down to 0 to 2.5V for my ADC. I'm concerned that using a resistive voltage divider will affect signal quality. Is this true? If it's not true, what value…
lionheart
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Circuit for measuring high voltage DC voltage (up to 1000V)

I am a final year E&E student and I am trying to built a power meter that must be able to measure quite high DC voltages, up to 1000 V DC. I am measuring with a simple 12-bit ADC that has an input voltage range of 0 - 2.5 V. Would a simple voltage…
Eduan Shuda
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ADC is detecting a sine wave as several clusters of points

I'm using an ADC (ADS4129) running at 125MSPS. I'm applying a 100kHz sine wave to a low pass filter (fc=15MHz). The ADC is being driven differentially, as intended. When probing the input signal with a scope I see a decent sinusoid. My problem is…
user264107
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What is the meaning of "half bit" in this context?

In RS-232 specification, the stop bits can be 1, 1.5 or 2 stop bits...I wonder how it's possible to have half a bit? Also some ADC math uses 0.5bit precision in the IC specifications/datasheet. Can someone elaborate in this subject?
mFeinstein
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What is a differential ADC?

How does a differential analog to digital converter differ from a regular ADC?
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AVR 1.1V Internal ADC Reference Over-Voltage

If I use the internal 1.1V reference for the ADC, and my Analog input exceeds 1.1V, lets say 2.5V, is that harmful to my microcontroller? Or will ADC value simply clip (to 0x3FF) at 1.1V? For convenience, I am including an excerpt block diagram from…
vicatcu
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How to read high voltages on microcontroller?

I want to read high voltages, like ~50V, using a microcontroller. I plan to put this as an input into the microcontroller's A/D line. But of course, you shouldn't have voltage that high on the input of a microcontroller or it'll fry. How might I…
Jack
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Effective number of bits of 14-bit ADC

I have a 14-bit ADC. However, looking at the datasheet (see table 2 on page 5), the effective number of bits (ENOB) is always less than 12 bits. Why is my the DAC claiming to be a 14-bit ADC when it only has 12-bit accuracy? What is the point of…
Randomblue
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What is a one-bit ADC good for?

I have recently heard of the concept of a one-bit ADC, and have seen it implemented in the context of a sort of digital-to-analog converter (oddly enough), and I'm wondering, what is the point? Why not simply use a higher-resolution ADC, if higher…
Mark
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Mixed signal PCB layout for PSoC

I am developing a PCB for an analogue sensing application. It uses the internal ADC on a PSoC3. As usual, the application is very space constrained (11mm x 21mm), so I have had to make some compromises in the PCB layout which I would not have done…
Rocketmagnet
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Reading a huge number of analog sensors in real time

I'm trying to build a MIDI-like controller that has a neck like a guitar. On that neck, there is a huge matrix of pressure sensors. The controller will emulate 3 strings. The way this works is: There are 3 long strips of double sided copper tape…
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