Questions tagged [sampling]
Periodical measurement of an electronical property of a system, most often voltage.
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questions with no upvoted or accepted answers
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Can phase noise be averaged out?
I have an ADC sampling a downconverted RF signal at fs. I obtain N=2^15 samples of the RF input signal "fcarrier + fs/10".
The more I average, the more the entire noise floor shifts down (as expected,...
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How to properly compute noise power spectral density?
I am confused about two different definitions of Power Spectral Density (PSD) that I have seen online.
The first comes from the National Instruments LabVIEW documentation (1):
$$
PSD = \frac{PS}{\...
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Finite-duration signal in the time domain, means what exactly in the frequency domain?
I'm trying to understand exactly what restrictions a finite duration time domain signal has on its Fourier transform.
I found a helpful table in The Fourier Transform and its Applications by Ronald ...
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Reason for the degraded I2S signal
I'm working with one of the devices from the NXP's IMX family - the IMX93 evaluation board.
I've managed to setup the sound card drivers already, the next step was to test I2S signals output via the ...
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ADC sampling time longer than expected
I have noticed an unexpected behavior with the ADC of a STM32l0 microcontroller on one of my projects. I’m trying to read 3 channels as fast as I can. My signal is buffered with an OPA127 op-amp that ...
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Help understanding Sampling rate, ODR and oversampling of BMP390
I'm trying to understand how fast I can measure pressure changes with the Bosch BMP390 sensor, but there are a few parameters in the datasheet that are confusing me and I would like to understand how ...
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Decode chirping frequency with uC at center frequency of around 100kHz
Context
For my MSc project I'm building a chirping signal (a bit like LoRa) with a center frequency of 100 kHz. For now, the bandwidth is 10 kHz such that I have around 10 periods per chip. For ease, ...
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Types of sampling and signal processing: some conceptual questions
I'm studying signal processing and right now I'm going through types of sampling and how they apply, advantages and disadvantages. I have some questions about these concepts that I would like to ...
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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 ...
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STM32L0 ADC Interrupt Low Sampling Rate
My observed sampling rate is much lower than expected and I cannot understand why.
I have the discovery STM32L053C6 Discovery board and I want to use ADCs sampling. I started from the example ...
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Audio Sampling for Reactive Lighting
I'm trying to work on a reactive lighting project and I'm confused about a couple topics when it comes to sampling audio.
I want to be able to have RGB reactive lighting controlled by a ...
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SDR Bandwidth and sample rate
I saw that SDR has two parameter: bandwidth and sampling rate. I would like to know the difference between them because i saw a 56MHz bandwidth SDR but by looking at the chip used inside the sampling ...
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How do you find Image Rejection Ratio from doing FFT on ADC samples?
I'm trying to understand a particular code written by a former employee for measuring performance of an RX chain in a transceiver. I have to measure IRR(Image Rejection Ratio).
Certain input RF ...
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STM32F407 ADC setup problem: ADC sampling continues despite delay in code loop
I'm trying to control the sampling rate with a delay function. I'm using channel 0 on ADC at PA0. This is how I've set it up:
...
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Wheatstone bridge analysis
Hello,
I am facing issues in calculating few parameters for the following information. I am new to this concept of strain gauge, wheatstone bridge, and data acquisition system
Four resistive strain ...
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Why doesn't the sampling rate of the ESP32 go any higher than 10 kHz?
I put this simple code in the Arduino IDE. I expect a message in the serial monitor every second saying time for 50000 readings is 1 millisecond.
...
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How to minimize vTaskDelay in FreeRTOS?
I need to sample a signal with a sampling frequency in order to 2500 Hz. But, when i put any time in vTaskDelay(pdMS_TO_TICKS(time)) under 1 [ms], my programa start to bug. How can i fix this?
Note: ...
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Frequency domain analysis when sampling a switched (gated) integrator
I would like to use AC analysis (e.g. in spice) on a non-ideal op-amp integrator where the reset switch is open, and then apply a shaping function to the result of the AC simulation (in the frequency ...
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Huge spikes and sudden offset in accelerometer data (FRDM-K64F & ADXL357)
I'm working with vibration analysis on electric motors (AC). I have a mBed FRDM-K64F with a EVAL-ADXL357 connected to it - mounted onto a motor.
The device samples from the FIFO 4000 times per second,...
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1
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How does a fiber optic receiver converts the optical signal to an electrical signal
A fiber optic receiver needs to convert the incoming optical signal to an electrical signal so it can be sampled. How is this achieved in practice?
I believe a photodiode is used, but would a ...
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STM32 ADC: Multiple channels with different sampling rates
I am trying to figure out how the STM32 multiple channels ADC conversion works (regular group). Lets say I want to convert on two channels, channel 1 and channel 2, on ADC1 and the sampling rates are ...
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Delta Sigma Modulator for 2/3 Multi modulus divider used in FracN PLL
I have been trying to implement a Delta Sigma modulator for a 2/3 Multi Modulus divider. I am referring to Riley's paper: https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=229400
I have designed ...
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How to measure and sample oscillations in a LC tank using a Microcontroller
Since the oscillations in a LC tank starts with high amplitudes and dies gradually, and since the first oscillations are to some extent unpredictable in amplitude, how can one measure and sample such ...
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Effect of 2ASK Sampling Points on Bit Rate
"I reduced the only one sampling points while using 2ASK modulation, and the bit error rate increased by 20%. Can you help me with this?"
Question happens in this line t = 0:bitDuration/100:...
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Experiencing Much Higher Data Rate than Timer Interrupt Settings While Reading IMU Data via I2C on Arduino
I am currently using an Arduino MKR ZERO to gather IMU data from three MKR IMU SHIELD boards(BNO055 IMU). I have utilized the <Adafruit_ZeroTimer.h> library to set a timer interrupt with a ...
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Are the subjects "button debounce" and "Nyquist–Shannon sampling theorem" related or not?
My understanding:
Regarding A/D conversion of a signal: The Nyquist-Shannon sampling theorem states, that an analog signal can be fully reconstructed (D/A converted back) if the sampling rate is >= ...
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Fourier transform plot
A continuous-time signal x with bandwidth \$\frac{20π}{3}\$ rad/sec is
sampled with sampling period \$T_s = 0.1\$ seconds to obtain a
discrete-time signal \$x_s[n] = x(nT_s)\$ for all n. The discrete-...
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I want to divide a pulse in time axis and create more pulses
I need help with my project. I want to split a pulse on the timeline. I want to take the signal and divide it by 58 μs. Actually the time of the output signal is not important. I just need to generate ...
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Best way to drive high speed ADC with differential inputs
Currently I am using AD8137 to convert my single ended signal to a differential signal. The ADC I am using is ADC3422 from TI and the data sheet suggests a passive circuit to drive low frequency ...
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Convolution between bit stream sampled by N number of samples per bit with a channel modeled as low pass filter
I generated a bit stream in MATLAB, from the transmitter to be convoluted by the channel
I use MATLAB function "randi" between 0 & 1, so it generates random vectors of 0s & 1s and ...
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Digital up conversion and digital down conversion
Description:
I’m trying to use the standard sample rate of 61.44 MSPS on both sides of my digital transceiver(DUC and DDC,) so I’ll upsample my data from baseband data rate 3.84 MSPS to 61.44 MSPS ...
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Frequency converter for spectrum analysis
I have an oscilloscope/spectrum analyzer that has a maximum sampling frequency of 20MHz and I would like to analyze the spectrum of a higher frequency band (also 20MHz wide) for example 90-110MHZ to ...
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Sampling a continuous time signal in a DSP
We are tasked with sampling a continuous time signal in a DSP.
Before sampling, the signal goes through an analog filter of which I know the continuous frequency function H(ω). I also know the Fourier ...
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What should be my sampling frequency for a peak detector output where it is extremely important for me to capture the first time the peak occured?
Following is the output of the peak detector:
The amplitude is not important to me, however the time when the peak occurs is extremely important. So my microcontroller will have an algorithm like ...
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What happens if the signal frequency exceeds the sampling rate?
As the title states, I was wondering what happens to the frequency contents of the sampled signal of a pure sinusoidal signal that exceeds the sampling rate.
I am familiar with the shannon theorem and ...
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Calculating DAC samling rate from datasheet
I want to use the DAC121S101 DAC (attached) and was wondering if my sample rate calculations are correct.
Settling time is 10uS which means max sampling rate would be 1/10us= 100KHz, 100KSps
But need ...
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Why is the STM32 reference manual stating the wrong sample frequency for I2S?
This could be a misunderstanding but everything I have gathered and seen it looks like there's a disconnection on what the reference manual says.
On Pg. 2212, in the STM32H753ZI it states:
"The ...
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Osciloscope output timing header meaning and interpretation
I have obtained a set of readings from a set of oscilloscope data, RTA 4004 from R&S. the readings headings kind of puzzle me. It has an index.csv and multiple readouts.csv. The index.csv looks ...
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Typical rms values for random jitter in satellite communication
I'm trying to find typical values for random jitter in satellite communication and I'm not really finding any values in any documents. Most of the time I only find definitions for different jitter ...
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DAC update rate vs ADC update rate?
I am building a system for ultrasonic distance measurement that implements CDMA coding access. Therefore, I am using DAC with 3 outputs for generation of three different signals and an ADC for ...
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Relation between spectral leakage and the frequency of harmonics of a signal
I'm currently studying "Data Acquisition".
I read that when we have frequency/spectral resolution equal to a natural number, there will be no spectral leakage, for none of the harmonics.
However the ...
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How to measure the amount of light emitted back from a fiber optic cable?
I would like to build a setup where I use a light source to emit a signal over a fiber optic cable, and then measure the amount of light that is emitted back, e.g. by blocking/opening the other end of ...
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What are the appropriate pulse width and PRF for a pulsed Doppler sensor
I have a raw k-band transceiver, radar-based 24 GHz, motion detector, IPM-165.
and here is the datasheet:
https://www.innosent.de/fileadmin/media/dokumente/DATASHEETS_2016/Datenblatt_IPM-165_V8....
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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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sampling rate and bit resolution for Scanning Probe Microscopy
I am trying to compare two products and see which one offers higher performance in terms of sampling rate and bit resolution.
Below are the specs I was able to gather from product1 and product 2. (...
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Confusion with Nyquist theorem when sampling cosines versus sines
I'm having different results when sampling a cosine wave versus sine wave at different scenarios. I used MATLAB to plot waveforms.
I will try to give some examples to make clear where I'm stuck at.
...
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Constructing a reactive lighting system?
I've recently written a Matlab script to develop/simulate PWM output for RGB lights based on sampled audio input. I made this script with plans to actually construct a device that can run the ...
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Configuring the sampling frequency on STM32F4
How do I calculate the ADC Sampling Frequency if the (12 bit) ADC Clock of the MCU is 36MHz with a prescalar of 2?
I use a SysTick Event Handler to sample every 0.25 ms for example.
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Analog to digital controller-Sampling rate
One method to design a controller for a digital control system is to first design it in the s domain and then convert it. However, choosing a suitable sampling period is important.
In most problems ...
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Sample an AM Demodulated Signal to Bits
Is there a method for automatically sampling and converting an analogue signal into a series of bits?
I have an AM capture of a ceiling fan remote as a wave form, and so far I've been manually ...