Working EE stuff since mid 70's when I built my own 8008 "PC" with 2KB of SRAM for a school project. About 40 years of work experience and "officially" retired. I don't do social (that way I won't get hacked).

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...

Re: How to obtain impulse response of a room acoustics

Reply posted 6 months ago (01/23/2020)
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...

Re: Simulation a received Signal in Matlab ( y=H*x)

Reply posted 8 months ago (11/20/2019)
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),...

Re: What is this effect ?

Reply posted 10 months ago (09/09/2019)
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,...

Re: OFF TOPIC: A Question About PI

Reply posted 1 year ago (06/27/2019)
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...

Re: OFF TOPIC: A Question About PI

Reply posted 1 year ago (06/27/2019)
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...

Re: Is this time-domain aliasing?

Reply posted 1 year ago (05/27/2019)
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...

Re: inverse quantization

Reply posted 1 year ago (04/28/2019)
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...

Re: 50Hz and harmonics filtering

Reply posted 1 year ago (02/08/2019)
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...

Re: 50Hz and harmonics filtering

Reply posted 1 year ago (02/07/2019)
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...

Re: Time domain signal slikes

Reply posted 1 year ago (01/15/2019)
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....
"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...

Re: Machine learning and detection in noise

Reply posted 2 years ago (09/16/2018)
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...

Re: Tones in sigma delta modulator and dithering

Reply posted 2 years ago (07/26/2018)
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...)

Re: Tones in sigma delta modulator and dithering

Reply posted 2 years ago (07/25/2018)
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...

Re: Fundamental frequency of a Guitar string

Reply posted 2 years ago (06/29/2018)
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...

Re: Fundamental frequency of a Guitar string

Reply posted 2 years ago (06/29/2018)
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...

Re: THD estimation: FFT vs Periodogram

Reply posted 2 years ago (06/20/2018)
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...

Re: Impulse behavior of FIR LP filter

Reply posted 2 years ago (01/11/2018)
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...

Re: Upsampling of data

Reply posted 3 years ago (11/20/2017)
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...

Re: Differential frequency measurement

Reply posted 3 years ago (10/08/2017)
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...

Re: Differential frequency measurement

Reply posted 3 years ago (10/08/2017)
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...

Re: SNR measurement with fixed-point FFT

Reply posted 3 years ago (09/22/2017)
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...

Re: SNR measurement with fixed-point FFT

Reply posted 3 years ago (09/22/2017)
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...

Re: SNR measurement with fixed-point FFT

Reply posted 3 years ago (09/21/2017)
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...

Re: DSP Windowing function

Reply posted 3 years ago (08/23/2017)
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"...

Re: Burg's Recursion anomalies

Reply posted 3 years ago (08/20/2017)
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...

Re: A million UARTs....

Reply posted 3 years ago (06/03/2017)
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...

Re: complex values in Short-time Fourier Transform

Reply posted 3 years ago (06/02/2017)
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,...

Re: I need help

Reply posted 3 years ago (05/17/2017)
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,...

Re: Subharmonic distortion?

Reply posted 3 years ago (04/28/2017)
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...

Re: MCUs with hardware ids.

Reply posted 3 years ago (03/16/2017)
To me, "hardware ID" implies processor version. This may include additional information regarding the specific step, etc. of the processor (for "work-arounds")....

Re: Standard deviation in DSP

Reply posted 3 years ago (03/12/2017)
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....

Re: Standard deviation in DSP

Reply posted 3 years ago (03/12/2017)
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...

Re: measure signal power

Reply posted 3 years ago (03/03/2017)
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...

Re: Any fancy idea for an algorithm ?

Reply posted 3 years ago (02/21/2017)
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...

Re: PLL in presence of noise

Reply posted 4 years ago (07/26/2016)
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...

Re: "System Identification" Ideas

Reply posted 4 years ago (07/24/2016)
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...

Re: Zero IF vs Low IF receivers

Reply posted 4 years ago (07/10/2016)
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...

Re: fft combinations

Reply posted 4 years ago (07/09/2016)
I believe the term "zero padding" is a misstatement common to all textbooks (that I have seen) which should be replaced with "average padding". If taken literally...

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