Questions tagged [oversampling]

Anything related to oversampling, i.e. the process of sampling a signal at a much higher rate than the minimum required for its reconstruction (a.k.a. the Nyquist rate).

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Relation data-rate and bit-rate of ADC

I came accross the folowing question, where the accepted answer contains a formula showing the relation between bit-rate and data-rate for a delta sigma ADC. My question is, why that relation is valid....
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40 views

Sampling Frequency of a delta-sigma ADC

For instance, let's take this delta-sigma ADC: http://ww1.microchip.com/downloads/en/DeviceDoc/22088c.pdf To calculate the average current and other important values for various sampling scenarios I ...
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Definition of ENOB, SNDR for sigma-delta ADC

The general definition of each are the following: \$ENOB=\frac{SNDR_{max}-1.76}{6.02}\$ Where \$SNDR_{max}=10 \log{\frac{S_{s,max}}{S_n}}\$ And \$S_{s,max}\$ : maximum signal power \$S_n\$ : ...
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Data synchronization strategy for multiple sensors in BLE application

I am working on a battery sensitive BLE project which combines the MAX30003 ECG sensor and the LSM6DS3 accelerometer. Communication with both of these devices is made through SPI. The optimal sampling ...
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46 views

Increasing SNR through sampling and coherent integration

Let's say I have simple BPSK scheme and a receiver RF stage such that I have an ideal analogue bandpass filter with bandwidth \$ f_{bw} \$ and then a down converter and finally a sampler. I am trying ...
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2answers
192 views

Quantization error in ADCs and sampling speed

Assertion: The noise due to quantization error for an ideal 12-bit ADC gives a signal to noise ratio of 74dB, assuming a signal with full dynamic range at the input. Suppose I was using an ideal ADC ...
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4answers
179 views

Does SNR improve at higher sampling rates for a low pass filtered signal?

Let's say we want to extract 1Hz signal from a noisy signal by using a LPF. And assume we have sampled it with 100Hz sampling rate. If we would have sampled it with 1kHz sampling rate and use the ...
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1answer
472 views

Sampling data at 5MHz with 50Mhz clock in Verilog

I'm trying to make a controller for the MAX31855 thermocouple IC. My FPGA works at 50MHz and this IC works at 5MHz, so I'm using a frequency divider to get the 5MHz clock signal. Now the IC is ...
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1answer
882 views

ADC driver design for oversampling

I'm interested to sample an AC signal in the range of 5kHz - 20KHz with the STM32L432KC microcontroller. This microcontroller has a hardware oversampling feature, i.e it can take the average of ...
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1answer
107 views

Decimate ADAR7251 Sigma-Delta ADC Output

I'm working with a Analog Devices ADAR7251 Sigma-Delta ADC. It has multiple sample rates to choose from (1800 kSPS, 1200 kSPS, 900 kSPS, 600 kSPS, 450 kSPS, and 300 kSPS) but my application requires ...
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1answer
103 views

Static error in analog-to-digital conversion

I'm testing ADC and quantization noise on a microcontroller (dsPIC33EP64GS506), but I've realized that I have a static error in a digital signal. I measure a DC voltage on a voltage divider and my ...
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55 views

Oversampling on dsPIC33EPXXGS50X family

I'm trying to implement oversampling on a dsPIC33EP64GS502. According to the datasheet and the ...
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3answers
1k views

Fast Fourier Transformation of incomplete signals

I would like to perform a FFT on a signal with equally sampled values of which some are missing. (Actually, they are not even missing, but simply erroneous, so I can't use them, but I can detect when ...
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3answers
264 views

RF over sampling to increase SNR

Using a 32MHz pic processor, and over sampling the demodulated analog output of an RF receiver (instead of the data slicer output) is it possible to use averaging to reduce increase the SNR of the ...
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3answers
2k views

Calculating FFT for only part of full frequency range?

Earlier I asked a question here about performing FFT at lower frequencies but still at high sample frequencies. I was under the impression that the FFT was inherently calculated at every frequency 0->(...
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3answers
743 views

ADC undersampling AND oversampling

I need to accurately measure a narrow band signal (of about 200Hz) centered in a part of spectrum that is many times its band (at about 20kHz). I have only a 12 bit ADC that is relatively fast (5 MSPS)...
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2answers
396 views

Is using a high sample rate on an oscilloscope ever a bad thing?

A while back i was gathering some ECG data for a colleague at a reasonably high sample rate (around 20kHz - 100Hz is enough for ECG). She came back to me and asked me to regather the data at a lower ...
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1answer
471 views

Calculating bits/sample from a digital MEMS microphone

I'm thinking of using a digital MEMS microphone in a project - looks like it would save on some parts: no need for an amplifier and ADC. The output from the microphone is PDM and I'd need to convert ...
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1answer
569 views

Am I getting DC bandwidth correctly?

I am computing Johnson and shot noise in a DC circuit, where I have an Arduino Due sampling with "delay(100);", i.e. at 10Hz. Sampling rate and bandwidth follow Nyquist sampling theorem. According ...
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2answers
266 views

Gain Resolution after delta-sigma (ΔΣ) analog-to-digital converter (ADC)

Is it possible (effective) to do oversampling and apply extra Moving Average Filter with a delta-sigma (ΔΣ) analog-to-digital converter (ADC)? More detailed: The ADC (ADS1258) I chose has an ...
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1answer
421 views

Digital Low-Pass Filter When Oversampling Audio

The human ear can hear sounds up to ~ 20KHz. Some ADC's oversample. For example, to capture frequencies up to 20KHz, an ADC converter might sample at 160KHz. The steps are: 1. Filter the audio with an ...
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2answers
1k views

Would oversampling reduce in-band signal noise floor?

I understand that oversampling will reduce quantization noise floor. Would oversampling also reduce the noise floor of the noises in band of interest? *******EDIT 20150320********* The correct ...
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1answer
118 views

Sampling: how to determine a “good” sampling rate based on a given filter

I assume that the sampling rate is w_s = 2w_max if we have an ideal low-pass filter that nulls frequencies whose absolute value is higher than that of w_max. Therefore, that the only reason for ...
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3k views

About the meaning of “oversampling”

Recently, I heard one of my colleague said "the 16-bits ADC is enough for us, we can use 'oversampling' tech...". Finally I figured out his "oversampling tech" means to sample many many cycles (AC ...
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1answer
362 views

Any tricks to generate triangle wave to add to analog signal for oversampling?

I want to increase the effective resolution of the ADC by oversampling and decimation. Unfortunately the signal I'm realing is too clean, so I would like to add a bit of artificial noise (1LSB peak to ...