Questions tagged [aliasing]

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2
votes
1answer
90 views

Is using passive anti-aliasing filter with its transfer function instead of an active filter common or reliable?

I need to ask this general question with an example for clarity. Imagine I have to measure a signal with BW of 5kHz and I need to make a unity gain active anti-aliasing filter with a steep roll off ...
12
votes
6answers
2k views

Why does increasing the sampling rate make implementing an anti-aliasing filter easier?

From an answer to a question regarding sampling rate and anti-aliasing filter I read the following: The closer you get to the theoretical minimum sample rate, the more difficult the analog filter ...
0
votes
1answer
67 views

Calculating sampling frequency off of estimated stop band attenuation

I'm trying to calculate what I will have to set my microcontroller's ADC sampling rate at in order to sample a band of 500kHz to 1.6065MHz without aliasing. Some constraints here are that I have to ...
0
votes
1answer
44 views

Can an amplifier slew rate be used as a low pass anti-aliasing filter?

A slew rate calculator says that for an arbitrary 100MHz signal a minimum slew rate of 1884V/μS is required. If I used an amplifier with that exact slew rate is it also a low pass filter? It seems ...
2
votes
2answers
1k views

what is memory aliasing?

I was reading about ARM M series and somewhere it was written that: "the flash memory area is aliased from address 0x0000 0000". what does it mean?
1
vote
1answer
115 views

How do you find the resulting frequency of sampling a tone at too slow of a rate?

For example, I have a 1500 Hz tone that I am going to be sampling at 1200 samples/second. How would I figure out the tone resulting from this sampling?
1
vote
2answers
236 views

Anti-aliasing filter with a higher corner-frequency (>10 MHz)

I'm currently working on a design with an adc3424 ADC with 125 MHz sampling frequency. This is my first design with an ADC and I assumed picking an anti-aliasing filter (AAF) would be a trivial task. ...
0
votes
1answer
348 views

Anti-Aliasing Filter example

I need help in solving the below question. Bandwidth of the signal is 1KHz. Use a 12-bit ADC with SNR of 78dB for sampling. the sampling frequency is 12KHz. Choose suitable filter order and cut-off ...
1
vote
1answer
102 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 ...
0
votes
1answer
530 views

A question on aliasing and sampling in a measurement system

Before asking my question here is the scenario how the voltage signals are used: Where I work some are performing data acquisition of four DC signals through four channels by a daq device at a ...
1
vote
1answer
99 views

Specific noise while using arduino ADC in free running mode

To make an oscilloscope in matlab environment, for data acquisition on arduino side, when inbuilt analogRead() is used, it's working fine, but with very low ...
2
votes
3answers
1k views

ADC anti-aliasing filter

I bought a 16bit, 250kSPS AD7689 ADC. The circuit I am designing will amplify voltage (from 300uV up to 300mV) across a current-sense resistor (by 13x) to match 4.096V reference and feed this into an ...
0
votes
1answer
165 views

Sampling and Aliasing Problem

I have this problem where I was able to solve for both a and b but I am stuck on c and d. For part a I came up with 0 Hz, 4.77 Hz...
0
votes
2answers
138 views

How to determine the frequency of input signal from Sensor to ADC?

I am using a Pressure Sensor that gives out an Analog Output of 0V to 10V depending upon the sensed pressure. I am trying to design a filter (or at least determine some starting RC values) for the ...
2
votes
3answers
4k views

Divider and lowpass combined

I am using the following circuit for two purposes: As a voltage divider, to reduce DC sensor output to a range suitable for my ADC. As a lowpass filter, to remove high frequency noise from the signal....
5
votes
2answers
1k views

Anti-Aliasing filter design

I appreciate that different applications have different criteria, but could someone give a ball park figure of how much attenuation is needed for an anti aliasing filter at the Nyquist frequency to ...
1
vote
2answers
3k views

Aliasing vs Imaging. What is imaging?

In DSP for audio, I understand what Aliasing is (fixed with an anti-aliasing filter), but there is also something called Imaging (fixed with a reconstruction filter). Aliasing is when a higher ...
1
vote
1answer
940 views

Guitar signal preamplifier - ADC input to STM32F4

This is for a DSP project. I am trying to prepare my guitar signal for as best as possible ADC response in order to detect harmonics to the 5th of the highest note of the guitar (1175 Hz for 22 frets),...
0
votes
1answer
430 views

Sampling Anti-Aliasing Filter Bandwidth

if i'm using Sampling frequency less than Nyquist Sampling frequency, Aliasing will occur which will scramble the whole signal, so one solution is to use anti-aliasing filter How can i calculate it'...
0
votes
2answers
115 views

Anti-aliasing filter as notch and lowpass

In order to reach a steep attenuation for an analog antialiasing filter, there are issues if a high Q notch filter is followed by a low order lowpass filter (or vice versa)? The notch resonance could ...
-1
votes
2answers
187 views

Sampling alias phase when undersampling

I have to measure the sum of the magnitude of two sinusoidal signals and I think I can exploit the undersampling method in order to superimpose the alias of the sinusoid at the higher frequency over ...
2
votes
1answer
1k views

Nyquist frequency mirroring

I need someone to check my understanding of Nyquist frequency. I understand it in the following manner. $$F_{nyquist} = ( F_{sampling}/2 ) * n$$ where n is an integer (negative and positive). For ...
0
votes
1answer
388 views

Cyclical output counts from a D Flip Flop, what is this effect called?

While working on a frequency divider/counter (in this case a frequency subtractor) using flip-flops, I discovered a strange effect in a D flip-flop when I left the clock at a constant frequency, but ...
0
votes
1answer
83 views

Sampling frequency range of an discrete signal

Is it possible to detect each and every frequency above the nyquist frequency? Or this can be also discrete Thank you.
2
votes
1answer
140 views

How to measure energy distribution

I want to evaluate the energy flow in a battery powered system. So when the system runs a specific task the energy distribution between the different loads can be obtained ( similar to a Sankey ...
1
vote
0answers
135 views

why my DAQ signal is a noisy signal?

background: My goal is to use an Arduino with two proximity probe (sensors) to achieve some output. It is worth mentioning that the output of the proximity probe has two components: DC output that ...
7
votes
3answers
324 views

Measuring low-duty-cycle supply current

I am trying to measure average current draw of low-duty cycle, low current devices. For example, a Bluetooth Low-Energy device might draw 16 mA during the radio transmissions (for a millisecond or so)...