Art Mezins (@artmez)
Have you confined yourself too much? Try a different accelerometer, at least at first, get that working and then go back. Don't try to do realtime, since that can...
You state a lot of facts but give no details. You don't even label the graph. There are more questions than answers. "quantise the levels to DAC resolution" --...
Without going into details that I don't have experience in, my only comment is that the "plane wave" assumption is based on a far field signal and not a near field...
ADC data sheets provide additional clues based on the ADC's input bandwidth. Some of that is based on how fast the ADC can convert. When sampling a signal that's...
Frankly, I can't even read any of the images -- they're too fuzzy. And the scope shot is at a "bad" angle for trying to make any sense of the screen (I don't have...
Even simulated data needs to follow Nyquist rules (not just a good idea, "it's the law"). Simulated data has still has quantitization error since it's not continuous...
To see if it's the ADC frontend or the SW processing, synthesize some data and pass it into your SW. If that's OK, then it's a HW problem, otherwise it's SW.Never...
A good, really low cost but very capable choice with lots of backing that isn't a big commercial push is the Teensy 4.1: https://www.pjrc.com/store/teensy41.html PRJ...
Lots of good info here, but some bits are misleading. "decimation by 4" is not a "thing -- it's actually averaging in sets of 4, since the effect of averaging is...
From what I can understand from your statement, it would seem that nothing has been violated mathematically. As a caveat, I've never done this in any of my work. Since...
Add the APE format to the list of lossless codecs. I just saw some recent Bluetooth offerings from China that support that, and WAV and the aforementioned FLAC format....
Seriously, download and install Audacity. It's a great tool for exploring and playing with audio and literally "shows" you graphically the signal. I went to the...
Zero mean or AC coupled -- they're the same. But for the range analysis, they needn't be zero mean. Composite signals and look really strange (e.g. white noise)....
I've been caught! Thanks for that. I do forget that's the official way to do this. The 6.02 in dB is essentially the power of two squared.What I showed is a way...
To calculate the effective number of bits (ENOB) of a recording, scan all the samples to determine the min and max values. From that, then:ENOB = Ceiling(log(max...
There exists no means to perfectly reduce in-band noise -- ever. If the noise is 1 Hz away, it will still affect the measurement of the signal due to the filter's...
I'm guessing that alfa < 1, otherwise, there may be uncontrolled bit grow (and a need for saturation logic in the processing path).Looking at your figure, I...
This is not mean to sour your endeavors or any advice given here (which is mostly excellent). It's unclear what your end purpose is for doing this, but that leaves...
I, and I expect others too, are reluctant to "help" with such "obvious problems" (pretty much your words). You may understand the issues, but you don't want to analyze...
Not completely sure I fully understand your problem description. You have data that is 1000 times oversampled that needs to be downsampled (presumably by 1000),...
Agreed that it's totally saturated/clipped, especially if you "view" it on something like Audacity. But this may need to be fixed early in the generation process,...
Thanks, for that link. It was excellent (he is the most pedantic mathematician I have ever encountered, but I meant that is a good way). I watched it at x1.33 speed...
I remember that clip from the TV series "Person of Interest". I recall my calculus teacher saying something similar, but more like "every finite number" is contained...
I'm baffled. I found an example of "time aliasing" on this site, but it was in relation to FIR filtering, which puts the time domain samples in the frequency domain...
I confess complete ignorance of the term "inverse quantization". I googled and found two two references whose contexts related to DCT of images. Is that what...
By "Is the sampling harmonic with the desired signals?" I meant what is often called synchronous sampling. For example, for a 30 Hz signal, a sampling rate of 1200...
What I see as the big issue is the same one I see all the time: insufficient defining data. It's hard for anyone to guess at a solution when the problem is unspecified.I also...
You definitely need to provide more details, and in so doing, may reveal to yourself what the problem may be. As suggested by others already: [1] maybe an ADC saturation...
First, this depends on what is meant by "complex" sinusoid? I'm guessing the intended meaning is that the signal contains sine waves of multiple frequencies....
Re: Why am I getting the same frequency response plots when one has aliasing and the other does not?
"It is only valid to say that all these frequencies will have same samples if sampled at an ADC" is conditionally right, but only if the the signal is within the...
That resembles a "genetic algorithm" (GA) process (and goes by other names), more than AI. The BIG issue is how to set (train) limits, especially if this will be...
You can buy spread-spectrum clocks for microprocessors and other uses just for that reason (see: http://www.ti.com/clock-and-timing/generators/spre...)
Adding noise to any digital modulation process with large harmonic spurs on its output is effective at spreading the spurs' energy to meet FCC testing spurious...
I like it. I don't recall ever running across that anywhere until now.Maybe another way to "see" this is imaging doing what the Egyptians did when using a measuring...
You said you're measuring the "period", so it seems you are doing this digitally, right? Then an issue that can occur for low frequency digital inputs is their limitation...
While I am unfamiliar with the harmonic behavior of a plucked string, I do know a bit about harmonics generation in equipment. Second harmonics can be caused by...
Maybe I'm missing something. I "thought" that a periodogram "was equivalent to" an FFT for "properly sampled data". So, periodogram should not enter into the discussion...
I'm not sure I get your "point". You seem to describe an ordinary audio speaker, whose construction has innumerable forms. If what you ask is about audio speakers,...
While I have no definitive answer, my guess is that up-sampling is like a high-pass process, and introduces noise. This noise is then smoothed by the subsequent...
For a more complete picture of the problem and its solution, state your coefficient resolution. If that is too small, then the 1% target error may be eaten by quantization...
tomb18: Just think about what you just said as you described your "problem". This sounds like an ordinary case of interpolation, which when I went to school in...
So there are 3 sources of frequency and phase error: [1] the original modulation signal, [2] the SSB carrier generator (which could be reduced if it was synchronized...
PC sound cards use 100 ppm or better crystals. That is 10 times more accurate than your stated 0.1% transmit accuracy.You earlier stated "..but are subject to...
I'm not sure what you meant by removing the DC offset of the RAND function. It should be zero mean if constructed correctly.The reduction can be close to that as each...
Then I suspect that your input either your input is corrupted and/or the ADC ENOB is much less than 16 at the frequency you are using it. However, if your noise...
I'm sure MatLab is OK, but you really haven't provided enough information. What was the level of the "16 bit signal"? How many points in your FFT? Was the signal...
This problem seems intractable as stated. There is insufficient oversampling to do a decent job of capturing the underlying "signal". There is no mention of a Nyquist...
Never discount the benefits of googling something, which too often is greatly affected greatly by how a search is phrased. I used "dsp window function for fpga"...
Not pertinent per se, but went to http://www.emptyloop.com/ to find that reference, got distracted by a tool he has (unlocker) to delete "sticky" files (I have...
As a general observation for any kind of digital transmission: a header generally serves for synchronization (e.g. clock) and the tail often serves to prevent...
Seriously sounds like a class project. Getting "mentors" to help is fine, but you won't get far if you rely on others to do your work!My standard admonition before...
What do you mean EXACTLY by distorted? A graph would help.If imag/real is near an arctan asymptote of a pi/2 increment, then math precision gets in the way. Also,...
I like to not only look at the math, but the physics too. Some of this could be analog frequency related, the photon saturation characteristics of the photo sensor,...
I have a couple of guesses:[1] zero-cross distortion - can be due to CMOS inputs or outputs whose P/N transistors don't switch "perfectly".[2] if there is some...
I agree with Tim: define what "you" mean by dynamic range. Often defining a problem exposes the solution.Generically, dynamic range is taken to mean the peak-to-peak-ness...
Not exactly my field, but...An RF front-end, regardless of the bandwidth of its input, has only finite signal input level capacity. Some designs are better than...
To me, "hardware ID" implies processor version. This may include additional information regarding the specific step, etc. of the processor (for "work-arounds")....
However, DC can be an important signal component. If the signal under test is a direct demodulated version of an RF signal, then for AM modulated signals (e.g....
I'm an old-time embedded guy. I tend to automatically see problems from an embedded perspective and since the workproduct of many of these articles is destined for...
I have another observation. It has been my experience that an arbitrary "long term average" may not be enough for an accurate measurement if the window length...
One point missed so far is that a reflected acoustic wave can undergo a 180 deg phase reversal like EM waves. See http://physics.stackexchange.com/questions/23847/w...The...
Perhaps if the objectives of this "comparison" could be stated clearly, that would lead directly to a course of action. Above, you stated "shifted" but even that...
If I had to guess, I would say that that first cycle is affected by the discharge/charge of a coupling capacitor (something I ran into about 30 years ago). One could...
This maybe stating the obvious, but are you prefiltering the input? Today's electronics have crazy wide bandwidth that lets in lots of noise. Do you have a range...
Forgive my pedantism, as I tend to ramble. The best solutions can only be found from the best problem statements, and I find the problem statement too sparse...
DC spikes can also be simply due to the RF carrier level for AM signals or other types of signals with poor carrier suppression. An (AM) receiver with AGC tries...
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