What is a oversampling ADC?

What is a oversampling ADC?

Oversampling is a cost-effective process of sampling the input signal at a much higher rate than the Nyquist frequency to increase the SNR and resolution (ENOB) that also relaxes the requirements on the antialiasing filter.

How does ADC oversampling work?

Oversampling and averaging is done to accomplish two things: improve SNR and increase the effective resolution (i.e., increase the effective number of bits of the ADC measurement). Producing a lower noise floor in the signal band, the oversampling and averaging filter allows us to realize 16-bit output words.

How do I increase my ADC resolution?

The accuracy of a low-resolution ADC can be improved by oversampling the input signal using the ADC and subjecting it to low-pass filtering, using a FIR filter to filter out the quantization noise, and then decimating it.

How does oversampling reduce noise?

This technique decreases noise in the bandwidth of interest by “shifting” it to higher frequencies where it has less effect on your signals of interest. This in effect “shifts” quantization into higher frequencies. Oversampling does not decrease the total noise power, it simply distributes it at higher frequencies.

Why is oversampling bad?

Random oversampling duplicates examples from the minority class in the training dataset and can result in overfitting for some models. Random undersampling deletes examples from the majority class and can result in losing information invaluable to a model.

Does oversampling improve accuracy?

Oversampling only helps improve precision if your measurements are subject to randomly distributed, zero-mean noise. If the noise is limiting the effective precision of your measurements then averaging multiple samples will improve the precision of your results.

What is the resolution of a 12 bit ADC?

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.

What is the resolution of a ADC?

The ADC resolution is defined as the smallest incremental voltage that can be recognized and thus causes a change in the digital output. It is expressed as the number of bits output by the ADC. Therefore, an ADC which converts the analog signal to a 12-bit digital value has a resolution of 12 bits.

Is oversampling good or bad?

As you can see, oversampling is really a very good technology and it solves a lot of problems. It can be said that, based on the digital filter, over-sampling technology is perfect at frequency domain, even the very simple digital filter, the performance in frequency domain is awesome.

Is undersampling better than oversampling?

Oversampling methods duplicate or create new synthetic examples in the minority class, whereas undersampling methods delete or merge examples in the majority class. Both types of resampling can be effective when used in isolation, although can be more effective when both types of methods are used together.

Why is oversampling not preferred?

the random oversampling may increase the likelihood of occurring overfitting, since it makes exact copies of the minority class examples. In this way, a symbolic classifier, for instance, might construct rules that are apparently accurate, but actually cover one replicated example.

What is the disadvantage of oversampling?

The main disadvantage with oversampling, from our perspective, is that by making exact copies of existing examples, it makes overfitting likely. In fact, with oversampling it is quite common for a learner to generate a classification rule to cover a single, replicated, example.

How to use oversampling to increase ADC resolution?

Here’s how to use of oversampling to achieve extra bits of resolution for an ADC integrated in an MCU. We start by examining the frequency-domain transfer function of a multibit ADC operating on a sinewave input signal.

How to increase dynamic range of SAR ADCs?

The oversampling capability is implemented in the AD7960/AD7961 evaluation software using a simple averaging of the ADC output samples, meaning, and summing the number of ADC samples and dividing it by the oversampling ratio to get the increased dynamic range.

Which is the sample frequency of the ADC?

The ADC samples this input at a frequency Fs, which (according to Nyquist theory) must be at least twice the input-signal bandwidth. An FFT analysis (left graph of Figure 1 ) shows a single tone with lots of random noise (known as quantization noise) extending from DC to Fs /2. Click on image to enlarge.

How does oversampling and averaging improve measurement resolution?

Oversampling and averaging can be used to increase measurement resolution, eliminating the need to resort to expensive, off-chip ADCs. Oversampling and averaging will improve the SNR and measurement resolutionat the cost of increased CPU utilization and reduced throughput.