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title = "Analog to Digital Converters"
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author = ["Thomas Dehaeze"]
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author = ["Dehaeze Thomas"]
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keywords = ["electronics"]
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draft = false
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category = "equipment"
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Tags
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: [Electronics]({{<relref "electronics.md#" >}})
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: [Electronics]({{< relref "electronics.md" >}})
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## Types of Analog to Digital Converters {#types-of-analog-to-digital-converters}
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<https://dewesoft.com/daq/types-of-adc-converters>
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- Delta Sigma ([Baker 2011](#orgbdb61af))
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- Delta Sigma <baker11_how_delta_sigma_adcs_work_part>
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- Successive Approximation
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@@ -33,11 +33,11 @@ Let's suppose that the ADC is ideal and the only noise comes from the quantizati
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Interestingly, the noise amplitude is uniformly distributed.
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The quantization noise can take a value between \\(\pm q/2\\), and the probability density function is constant in this range (i.e., it’s a uniform distribution).
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Since the integral of the probability density function is equal to one, its value will be \\(1/q\\) for \\(-q/2 < e < q/2\\) (Fig. [1](#org4bd731c)).
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Since the integral of the probability density function is equal to one, its value will be \\(1/q\\) for \\(-q/2 < e < q/2\\) (Fig. [1](#figure--fig:probability-density-function-adc)).
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<a id="org4bd731c"></a>
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<a id="figure--fig:probability-density-function-adc"></a>
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{{< figure src="/ox-hugo/probability_density_function_adc.png" caption="Figure 1: Probability density function \\(p(e)\\) of the ADC error \\(e\\)" >}}
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{{< figure src="/ox-hugo/probability_density_function_adc.png" caption="<span class=\"figure-number\">Figure 1: </span>Probability density function \\(p(e)\\) of the ADC error \\(e\\)" >}}
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Now, we can calculate the time average power of the quantization noise as
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@@ -59,13 +59,12 @@ Thus, the two-sided PSD (from \\(\frac{-f\_s}{2}\\) to \\(\frac{f\_s}{2}\\)), we
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\end{equation}
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<div class="important">
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<div></div>
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Finally, the Power Spectral Density of the quantization noise of an ADC is equal to:
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\begin{equation}
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\begin{aligned}
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\Gamma &= \frac{q^2}{12 f\_s} \\\\\\
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\Gamma &= \frac{q^2}{12 f\_s} \\\\
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&= \frac{\left(\frac{\Delta V}{2^n}\right)^2}{12 f\_s} \text{ in } \left[ \frac{V^2}{Hz} \right]
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\end{aligned}
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\end{equation}
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@@ -73,7 +72,6 @@ Finally, the Power Spectral Density of the quantization noise of an ADC is equal
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</div>
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<div class="exampl">
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<div></div>
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Let's take a 18bits ADC with a range of +/-10V and a sample frequency of 10kHz.
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@@ -87,7 +85,4 @@ The quantization is:
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{{< youtube b9lxtOJj3yU >}}
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## Bibliography {#bibliography}
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<a id="orgbdb61af"></a>Baker, Bonnie. 2011. “How Delta-Sigma Adcs Work, Part.” _Analog Applications_ 7.
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## Oversampling {#oversampling}
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