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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UART over sampling

I've read that for UART is over sampling used to recover some kind of “clock signal”. How is that exactly done and why is that needed? I already searched on the internet, but I didn't find any helpful ...
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Digital implementation of State Space

I have a question regarding a digital implementation of a State Space controller. I have some rules of thumb when designing; when implementing the observer as well as the sample frequency. I say that ...
3 votes
2 answers
517 views

May I write to a DAC chip slower than data is "sampled" at?

Will a DAC chip like MCP4921/4922 UDA1334ATS output at a higher rate than the samples are written to it? Like 16 kHz sampled data out (to the headset) but the processor just delivering new values at ...
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SAR ADC - DC Input Settling

I'm looking to use a SAR ADC with 1.6MSPS, and leveraging the integrated decimation filter to improve accuracy. I'm using Analog's Precision ADC Tool for the combination of my selected driver and ADC (...
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FPGA SPI slave doesn't work if driving it with the fast FPGA clock instead of with the SPI master clock (oversampling)

I have an slave SPI device implemented within an FPGA (Basys 3). I have had problems to route the SPI clock signal provided by a master to my slave device through one of the board PMOD pins (see this ...
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1 vote
1 answer
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System being subject to vibrations and G-forces : Crystal Oscillator or MEMS?

I'm planning on making an audio system that will be used in vibration-inducing environments (roller coaster rides that can reach up to 5/6G peaks and public transportation systems). One of its ...
0 votes
1 answer
148 views

Data Oversampling Transceivers

I am trying to find more information about data oversampling for transceivers when grabbing/sending a lower speed signal. I am looking into building a fully compliant HDMI 1.4b fpga core, and have ...
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1 vote
3 answers
104 views

Using a "non-audio" oriented DAC IC as an audio DAC

I'm starting a project that consists of a simple embedded 16-bit PCM audio player, where no actual DSP takes place, only plays PCM and outputs something you can then amplify. I am currently searching ...
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1 answer
329 views

Is there an easy way to oversample encoder input in STM32 microcontrollers?

I need to oversample the encoder input. Currently the single channel resolution is 2500 pulse/rev, thus combined channel resolution is 5000 pulse/rev. I need more or less 10 times higher resolution. I'...
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STM32 16bits ADC oversampling and 2^n values noise and glitch problem

I work on project using STM32H753VIT6 and its internal ADC. When I increase the sample rate some strange glitch/artifact with values around 2^n begin to appear into my signal after 48kHz. and I know I ...
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4 answers
198 views

ADC with integrated oversampling [closed]

Using a fast ADC it is possible to sample motor currents multiple times per PWM period (instead of a single synchronous measurement) and to average the results. This technique (oversampling) can help ...
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1 answer
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Oscilloscope design question

To begin with,I am not designig an oscilloscope but am curious about how certain parameters are determined. My questions might sound very trivial but I would be grateful if someone could answer them ...
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132 views

Using strategic sampling noise to increase sampling resolution

Dithering is used to add virtual resolution to an oversampling ADC, and for instance this discussion involves some of the math involved, and the criteria. Take for instance an Arduino with 10 bit ...
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stm32f401 usart: start bit detection sequence when oversampling by 8

I'm currently using usart on stm32f401. I'm wondering how the receiver detects start bit when oversampling by 8 is selected. The reference manual (RM0368) states that the start bit detection sequnce ...
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Oversampling, additional bits and a thermistor

Say we have a ten bit ADC (MSP430G2433) and a thermistor. We have the problem that two temperature measurements are too far apart, whilst the temperature has barely changed. So, we take more ...
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1 vote
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Understanding oversampling in control system

Oversampling means to sample at significantly more than the Nyquist Rate. I can well understand it in signal re-construction: more samples can improve the ADC's resolution, signal-to-error ratio, etc. ...
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1 answer
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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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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\$ : ...
2 votes
0 answers
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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 ...
0 votes
2 answers
365 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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2 votes
4 answers
666 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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Sampling data at 5 MHz with 50 MHz clock in Verilog

I'm trying to make a controller for the MAX31855 thermocouple IC. My FPGA works at 50 MHz and this IC works at 5 MHz, so I'm using a frequency divider to get the 5 MHz clock signal. Now the IC is ...
4 votes
1 answer
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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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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 ...
-1 votes
1 answer
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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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1 answer
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Oversampling on dsPIC33EPXXGS50X family

I'm trying to implement oversampling on a dsPIC33EP64GS502. According to the datasheet and the ...
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7 votes
3 answers
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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 ...
2 votes
3 answers
304 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 ...
5 votes
3 answers
3k 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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3 answers
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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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2 answers
616 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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3 votes
1 answer
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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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2 votes
1 answer
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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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333 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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1 answer
585 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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0 votes
2 answers
2k 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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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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6 votes
2 answers
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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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2 votes
1 answer
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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 ...
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