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Re: Advice for FM Demodulation Techniques

Reply posted 1 month ago (01/23/2020)
So you "have a quadrature FM signal that is modulated on a low frequency IF" which sounds to me that you have both \$i[n]\$ and \$q[n]\$ of a complex signal that...

Re: MSc Digital Audio Engineering Project Idea

Reply posted 2 months ago (01/11/2020)
Okay, do you know what "Convolutional Reverb" is?  What "Fast Convolution" is?Do you know what the Schroeder Reverb model is or the Jot Reverb model?  There might...

Re: Designing an IIR comb (peak) filter

Reply posted 6 months ago (09/03/2019)
it turns out that *every* digital filter is a comb filter (of sorts).  if the digital filter is a LPF, you will see comb teeth at every integer multiple of the...

Re: Carrier doppler shift and Signal doppler shift

Reply posted 6 months ago (08/21/2019)
i do not see why the Doppler shift effect should be any different for the modulation than it is for the carrier.  the whole signal gets scaled in time by a single...
okay, i understand this statement: "I have used a Farrow interpolator to do fractional rate sample rate conversion on only one of the signals..." but i am curious...
if you're interpolating (or sample rate converting) the stretched replica to make it the same length as the original signal segment, how do you know what the sample...
well, i don't have the fixed=point toolbox, but if you're plagued with limit cycles due to round-to-nearest quantization, my suggestion is that you use a technique...

Re: FFT Interpolation

Reply posted 7 months ago (07/26/2019)
...

Re: FFT Interpolation

Reply posted 7 months ago (07/26/2019)
But then you have to toss in the modulo indexing in order to use the theorems in your "(i.e., discrete Fourier transform)".  That modulo indexing makes it periodic.Uniform...

Re: FFT Interpolation

Reply posted 7 months ago (07/26/2019)
I would replace the word "finite" with "periodic".

Re: Adaptive Filter Theory: prequisites to learning

Reply posted 7 months ago (07/26/2019)
Stephan, your implementation of \( \LaTeX \) here leaves a bit to be desired.  It works erratically.  especially when i edit a post that had math previously appearing.if...

Re: FFT Interpolation

Reply posted 7 months ago (07/26/2019)
Well, this is an old issue with me and Eric that dates back to the mid 1990s on comp.dsp .  I must differ with Eric where he writes:"There do not need to be any...
I don't see any truncation or cast to a fixed-point value or any nonlinearity.  So I don't understand what the source of any limit cycle would be.At least, in my...

Re: Adaptive Filter Theory: prequisites to learning

Reply posted 7 months ago (07/14/2019)
The very basics of the LMS adaptive filter are not all that difficult to understand.  Perhaps ask a question about it at the Signal Processing Stack Exchange and...

Re: FIR filter shortening technique

Reply posted 8 months ago (07/11/2019)
yeah, what John says.  because reducing 1024 degrees of freedom down to 3 degrees of freedom might not so good.  even if your FIR taps are not adjacent to each...

Re: Fixed point exponentiation

Reply posted 8 months ago (07/03/2019)
i do now.  but it looks a little Maclaurenish to me.  since, ultimately, the power series will have to be finite (which is a polynomial), you will want (slightly) different...

Re: Fixed point exponentiation

Reply posted 8 months ago (07/02/2019)
but can't you develop a Cordic operation based on 2^x instead of e^x just as efficiently?  there might be an internal scaling operation in there that would be different...

Re: Fixed point exponentiation

Reply posted 8 months ago (07/02/2019)
it just seems to me, Brian, that especially for a fixed-point implementation, that 2^x is the simplest primitive and then use A^x = 2^(x*log2(A)).When it's base...

Re: Fixed point exponentiation

Reply posted 8 months ago (07/02/2019)
In this stackexchange answer are the coefficients for some short finite-order polynomials for evaluating (at a pretty good accuracy) a bunch of transcendental functions...

Re: Clock drift and compensation

Reply posted 8 months ago (06/28/2019)
well, it appears to me that you will need to perform Asynchronous Sample Rate Conversion (ASRC).  there are chips to do that, but if you have the sufficient unused...

Re: need help with adsp21489 ezkit programming

Reply posted 9 months ago (05/29/2019)
Okay, so I know the SHArC core instruction set pretty well and some of the key features that existed in the SHArC back in the olden daze (like 1995 with version...

Re: need help with adsp21489 ezkit programming

Reply posted 9 months ago (05/28/2019)
Do you have an ICE-1000 or some JTAG emulator with this EZKIT?If you don't use a JTAG emulator, I s'pose ADI provides some means of loading and running code, but...

Re: Aliasing in Radix-2 FFT - Decimation in time

Reply posted 10 months ago (05/09/2019)
"If the DTFT of a sequence has a bandwidth omega_max > pi/2, a downsampling by a factor of 2 is surely going to cause aliasing in the resulting DTFT."Yes it will. ...

Re: Aliasing in Radix-2 FFT - Decimation in time

Reply posted 10 months ago (05/09/2019)
Similarly to some filterbank and wavelet transforms, there is perfect reconstruction because the aliases have a way of killing each other off.But when thinking about...

Re: What's your favorite modern DSP chip?

Reply posted 10 months ago (05/06/2019)
I still have yet to really do any work on an ARM even though I am told that some C code I wrote (and tested with Xcode) found its application on a phone running...
I am only responding to the title of the post.It seems to me that not very many books that describe fast convolution consider the optimal size for the FFT and most...

Re: How to model analog effects and create convolvers.!!

Reply posted 10 months ago (04/19/2019)
There is more to the various "analog effects" than filters and convolution.  If you're trying to simulate a guitar amplifier with different cabinets, perhaps the...

Re: Time delay

Reply posted 11 months ago (04/08/2019)
no.  it's an alternative way of doing it.  using polyphase FIR, you have coefficients for an FIR filter for every fractional delay you want.Let's say your FIR...

Re: Spectral distortion measure - Itakura-saito distance

Reply posted 11 months ago (04/05/2019)
i have never heard of the "Itakura-saito distance" before.  i did know about the Log-Spectral distance which is in dB.the form of this the integrand is (x-1) -...

Re: As easy as PI

Reply posted 11 months ago (04/04/2019)
I dunno.  Sometimes mathematics is useful for economic analysis and projections that should influence politics.  It's politically useful to understand a runaway...

Re: How closely are control engineering and DSP related?

Reply posted 11 months ago (04/04/2019)
Not only is knowledge in DSP **very** useful designing digital controllers, but Control Theory has some concepts that are useful for DSPers that never got paid...

Re: Time delay

Reply posted 11 months ago (04/04/2019)
So my understanding is that you want a fractional-sample delay, where you specify in advance how much delay you want.1. If the delay is a fraction of a sample less...

Re: Application of computer with invertible arithmetic?

Reply posted 4 years ago (07/25/2016)
yeah, it was Sokolich (who was around the alt.sci.physics.acoustics newsgroup when it was active) not the goofy brit named Gareth.didn't remember that i was scraping...

Re: Application of computer with invertible arithmetic?

Reply posted 4 years ago (07/25/2016)
well, i never much hung around these specific parts.  this might be my very first DSPrelated post.i remember Bob Cain from the comp.dsp daze.  if i remember right,...

Re: Prewarping Fc, Q or both

Reply posted 4 years ago (07/20/2016)
alright, there are a couple of different issues that may (or may not) need to be de-conflated. i'm gonna try to keep the number of symbols minimized. \(dB_\text{gain}\)...

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