How is ADC measured?

How is ADC measured?

ADC has a resolution of one part in 4,096, where 212 = 4,096. Thus, a 12-bit ADC with a maximum input of 10 VDC can resolve the measurement into 10 VDC/4096 = 0.00244 VDC = 2.44 mV. Similarly, for the same 0 to 10 VDC range, a 16-bit ADC resolution is 10/216 = 10/65,536 = 0.153 mV.

How is ADC SNR measured?

SNR is a calculated value that represents the ratio of rms signal to rms noise. You then multiply the log10 of this ratio by 20 to derive SNR in decibels. As I mention above, an ADC’s ideal SNR equals 6.02N+1.76 dB, where N is the number of bits. You derive this formula by first defining the rms signal.

How is ADC ENOB measured?

ENOB is based on the equation for an ideal ADC’s SNR: SNR = 6.02 × N + 1.76 dB, where N is the ADC’s resolution. A real world ADC never achieves this SNR due to its own noise and errors. You can rearrange the equation to calculate an ADC’s effective N, or ENOB as we commonly call it: ENOB = (SNR – 1.76)/6.02 dB.

How is ADC measured in MRI?

The equation used to calculate the ADC value was as follows: ADC = −ln (S / S0) / b, where S0 is the signal intensity of no diffusion gradients and b is the b value. After data acquisition, all images were transferred to the workstation for analysis with manufacturer-supplied software.

How do you calculate sampling rate for ADC?

The sample rate for an ADC is defined as the number of output samples available per unit time and is specified as samples per second (SPS). Two aspects of sample rate that must be considered when selecting an ADC for a particular application are the minimum sample rate and maximum sample rate.

How is sinad of ADC measured?

The SINAD is found by computing the ratio of the RMS level of the input signal to the RMS value of the root-sum-square of all noise and distortion components in the FFT analysis, excluding the DC components.

How is SINAD of ADC measured?

How is INL calculated?

The INL specification is measured after both static offset and gain errors have been nullified, and can be described as follows: INL = | [(VD – VZERO)/VLSB-IDEAL] – D | , where 0 < D < 2N-1.

What is the difference between static and dynamic performance of ADC?

An ADC’s static performance is controlled by a value called noise free code resolution, or NFCR, usually defined as six times the Root Mean Square (RMS) input-referred noise at the ADC’s input pin. An ADC’s dynamic performance is controlled by a value I call aperture slew rate, or ASR.

How can I reduce the distortion caused by the ADC?

Nothing can be done externally to the ADC to significantly reduce the inherent distortion caused by its front end. However, the differential nonlinearity in the ADC’s encoder transfer function can be reduced by the proper use of dither (external noise that is intentionally summed with the analog input signal).

What is noise-free code resolution of an ADC?

The noise-free code resolution of an ADC is the number of bits of resolution beyond which it is impossible to distinctly resolve individual codes.

How can I improve the SFDR of a perfect ADC?

Dithering can be used to improve SFDR of an ADC under certain conditions (see Further Reading 2–5). For example, even in a perfect ADC, some correlation exists between the quantization noise and the input signal. This correlation can reduce the SFDR of the ADC, especially if the input signal is an exact sub-multiple of the sampling frequency.