Home > Quantization Error > Quantization Error In Adc

Quantization Error In Adc


Output size (bits) Signal Frequency 1Hz 1kHz 10kHz 1MHz 10MHz 100MHz 1GHz 8 1,243 µs 1.24 µs 124 ns 1.24 ns 124 ps 12.4 ps 1.24 ps 10 311 µs 311 The two parts of the ADC may be widely separated, with the frequency signal passed through an opto-isolator or transmitted wirelessly. Walden, R. p.107. http://caribtechsxm.com/quantization-error/quantization-error-and-quantization-step-size.php

CMOS Analog Circuit Design. Finding an optimal solution to the above problem results in a quantizer sometimes called a MMSQE (minimum mean-square quantization error) solution, and the resulting pdf-optimized (non-uniform) quantizer is referred to as The analysis of quantization involves studying the amount of data (typically measured in digits or bits or bit rate) that is used to represent the output of the quantizer, and studying humanHardDrive 35.813 προβολές 19:53 Lecture 18 - ADC Terminology, Offset and Gain Error, Differential Nonlinearity (DNL). - Διάρκεια: 35:35.

Quantization Error In Pcm

Although aliasing in most systems is unwanted, it should also be noted that it can be exploited to provide simultaneous down-mixing of a band-limited high frequency signal (see undersampling and frequency However, the time consuming steps in the Wilkinson are digital, while those in the successive-approximation are analog. up vote 2 down vote favorite 1 I have an formula for this "Maximum Quantization Error" but i dont know what it is based in. Many ADC integrated circuits include the sample and hold subsystem internally.

  1. Retrieved 19 August 2012. ^ Löhning, Michael; Fettweis, Gerhard (2007). "The effects of aperture jitter and clock jitter in wideband ADCs".
  2. Thank you. 22nd June 2005,16:25 22nd June 2005,16:52 #2 Kral Advanced Member level 4 Join Date Mar 2005 Location USA Posts 1,326 Helped 278 / 278 Points 11,626 Level
  3. Likewise, the speed of the converter can be improved by sacrificing resolution.
  4. ISBN978-0-470-72147-6. ^ Taubman, David S.; Marcellin, Michael W. (2002). "Chapter 3: Quantization".
  5. This difference is then converted finer, and the results are combined in a last step.
  6. Reconstruction: Each interval I k {\displaystyle I_{k}} is represented by a reconstruction value y k {\displaystyle y_{k}} which implements the mapping x ∈ I k ⇒ y = y k {\displaystyle

In an ideal analog-to-digital converter, where the quantization error is uniformly distributed between −1/2 LSB and +1/2 LSB, and the signal has a uniform distribution covering all quantization levels, the Signal-to-quantization-noise TV tuner cards, for example, use fast video analog-to-digital converters. Under normal conditions, a pulse of a particular amplitude is always converted to a digital value. What Is Quantization Typically the digital output is a two's complement binary number that is proportional to the input, but there are other possibilities.

Your cache administrator is webmaster. In an oversampled system, noise shaping can be used to further increase SQNR by forcing more quantization error out of the band. To circumvent this issue, analog compressors and expanders can be used, but these introduce large amounts of distortion as well, especially if the compressor does not match the expander. Slow on-chip 8, 10, 12, or 16 bit analog-to-digital converters are common in microcontrollers.

ADCs of this type have a large die size, a high input capacitance, high power dissipation, and are prone to produce glitches at the output (by outputting an out-of-sequence code). Quantization Step Size Formula Please try the request again. The steps are continued until the desired resolution is reached. The presence of quantization error limits the dynamic range of even an ideal ADC.

Quantization Error Example

It is therefore required to define the rate at which new digital values are sampled from the analog signal.

In applications where protection against aliasing is essential, oversampling may be used to greatly reduce or even eliminate it. Quantization Error In Pcm Is it a Good UX to keep both star and smiley rating system as filters? How To Reduce Quantization Error Digital Signal Processing 3.336 προβολές 8:45 GATE 2014 ECE Six transistor SRAM memory cell - Διάρκεια: 9:21.

Under normal conditions, a pulse of a particular amplitude is always converted to a digital value. navigate to this website For any ADC the mapping from input voltage to digital output value is not exactly a floor or ceiling function as it should be. W. (1974). This generalization results in the Linde–Buzo–Gray (LBG) or k-means classifier optimization methods. Uniform Quantization

The resulting signal, along with the error generated by the discrete levels of the Flash, is fed back and subtracted from the input to the filter. The essential property of a quantizer is that it has a countable set of possible output values that has fewer members than the set of possible input values. Forum New Posts Unanswered Posts FAQ Forum Actions Mark Forums Read Community Groups Reported Items Calendar Link to Us Quick Links Today's Posts View Site Leaders Activity Stream Search Help Rules More about the author The key parameters to test a SAR ADC are: DC offset error DC gain error Signal to noise ratio (SNR) Total harmonic distortion (THD) Integral non linearity (INL) Differential non linearity

The comparator reports that the input voltage is less than 8V, so the SAR is updated to narrow the range to 0–8V. Quantization Example The result is a sequence of digital values that have been converted from a continuous-time and continuous-amplitude analog signal to a discrete-time and discrete-amplitude digital signal. article by Walt Kester ADC and DAC Glossary Defines commonly used technical terms.

what should I look for?Top StoriesSitemap#ABCDEFGHIJKLMNOPQRSTUVWXYZAbout - Careers - Privacy - Terms - Contact Introduction Data domains and data conversion Choosing ADC's and DAC's Sampling rate Quantization Error Signal to Noise

References[edit] Knoll, Glenn F. (1989). The values can represent the ranges from 0 to 255 (i.e. This example shows the original analog signal (green), the quantized signal (black dots), the signal reconstructed from the quantized signal (yellow) and the difference between the original signal and the reconstructed Adc Converter Thank you. + Post New Thread Please login « What are the functions of a carrier? | Basic Charts for series AC circuits » Similar Threads [Methodology] - How to solve

The LSB is equal to the quantization step. This is essentially what is embodied in the Shannon-Nyquist sampling theorem. It is a rounding error between the analog input voltage to the ADC and the output digitized value. click site This analogous process may help to visualize the effect of dither on an analogue audio signal that is converted to digital.

The number is read from the counter. Its effect is to cause the state of the LSB to randomly oscillate between 0 and 1 in the presence of very low levels of input, rather than sticking at a The resolution Q of the ADC is equal to the LSB voltage. Handbook of Modern Sensors: Physics, Designs, and Applications.

Gray, Vector Quantization and Signal Compression, Springer, ISBN 978-0-7923-9181-4, 1991. ^ Hodgson, Jay (2010). However, if the dynamic range of the ADC exceeds that of the input signal, its effects may be neglected resulting in an essentially perfect digital representation of the input signal. CMOS Analog Integrated Circuits: High-Speed and Power-Efficient Design. Timed ramp converters require the least number of transistors.