CIC interpolation implementation

Started by Wilton Helm in comp.dsp6 days ago 7 replies

I sent this to Rick, but thought maybe a wider reading would be beneficial. I'm designing a CIC interpolating filter (N = 3, M = 1, R = 15 if it...

I sent this to Rick, but thought maybe a wider reading would be beneficial. I'm designing a CIC interpolating filter (N = 3, M = 1, R = 15 if it matters) and I came to a realization I hadn't had before and haven't ever heard anyone else mention. That often means there's something badly wrong with it, but I don't see it. Let's start with the traditional implementation:


wow. it starting to look like USENET is getting pretty dead.

Started by robert bristow-johnson in comp.dsp2 weeks ago 19 replies

this used to be a very active newsgroup. nothing happening since Oct 17 and now it's Nov 2. sorta gets eclipsed by Stack Exchange (which...

this used to be a very active newsgroup. nothing happening since Oct 17 and now it's Nov 2. sorta gets eclipsed by Stack Exchange (which allows for formatting math equations and pasting in graphics). r.i.p. comp.dsp i guess we all die sometime or 'nother. r b-j


Control loop Question

Started by Anonymous in comp.dsp4 weeks ago 1 reply

If you have say a speed loop for a motor and an inner current loop, what spec should the inner loop have relative to the outer? I am assuming the...

If you have say a speed loop for a motor and an inner current loop, what spec should the inner loop have relative to the outer? I am assuming the inner current loop should have a much higher bandwidth otherwise it will interfere with the outer loop. Is this how it is usually done?


Korenberg's fast orthogonal search

Started by Anonymous in comp.dsp4 weeks ago 1 reply

Has anybody used this algorithm? It seems to be what I need; fitting 2 or 3 sinusoids to sampled data, where those sinusoids have arbitrary...

Has anybody used this algorithm? It seems to be what I need; fitting 2 or 3 sinusoids to sampled data, where those sinusoids have arbitrary frequencies (not harmonically related as in discrete fourier transform).


POLQA (ITU P863)

Started by Mauritz Jameson in comp.dsp1 month ago 10 replies

I downloaded the P.863 POLQA source code from the ITU website. As far as I can see there is no guide to how the project should be built. So I...

I downloaded the P.863 POLQA source code from the ITU website. As far as I can see there is no guide to how the project should be built. So I created a new console application (empty project) in Visual Studio and added Main.cpp to the project. The first error I get when I try to build is: 1> ------ Build started: Project: polqa, Configuration: Debug Win32 ------ 1> Compiling... 1> Main.cp


Rayleigh vs. Nyquist

Started by RichD in comp.dsp1 month ago 1 reply

Consider the Nyquist criterion for sampling a continuous=20 waveform - 2x bandwidth - then the Rayleigh resolution=20 principle - peaks must...

Consider the Nyquist criterion for sampling a continuous=20 waveform - 2x bandwidth - then the Rayleigh resolution=20 principle - peaks must separate by at least 1 wavelength. =20 Don't these look much analogous? =20 Especially as =CE=BB =3D 1/f Ruminating a bit more... Nyquist sampling can be=20 viewed as a mandate to sample each period, at least=20 twice. And, Rayleigh mandates that...


How to convert from PDM to PCM ?

Started by Mauritz Jameson in comp.dsp2 months ago 34 replies

I have a client who is using a MEMS microphone (SPM1423HM4H-B, 3.125MSPS). The output of the microphone is a PDM...

I have a client who is using a MEMS microphone (SPM1423HM4H-B, 3.125MSPS). The output of the microphone is a PDM signal. Datasheet: http://media.digikey.com/pdf/Data%20Sheets/Knowles%20Acoustics%20PDFs/SPM1423HM4H-B.pdf In the client's test setup an emitter emits an acoustic signal. The emitted signal has frequency components around 40kHz. When I reviewed the client's setup, I noticed a c...


Future of Freescale parts

Started by boB in comp.dsp2 months ago

Since Freescale was bought by NXP and very possibly coming up, Qualcomm, have any of you heard or have any thoughts on the future of their...

Since Freescale was bought by NXP and very possibly coming up, Qualcomm, have any of you heard or have any thoughts on the future of their DSCs ? Do you think they'll obsolete these or keep their promise (so I'm told) that the parts will have a life of at least 10 years after their introduction ? Some parts came out in 2014 I think it was. MC56F82748 for example. I don't know how...


Troubles in simulating sharp edges

Started by Peter Mairhofer in comp.dsp2 months ago 5 replies

Hi, I am fighting this problem for two days now: I want to simulate a passive mixer (50% and 25% Duty Cycle) which is basically a switch...

Hi, I am fighting this problem for two days now: I want to simulate a passive mixer (50% and 25% Duty Cycle) which is basically a switch and hence can be modeled by multiplying the input with a rectangular waveform (or less harmonics). Suppose I have a clean sinusoidal LO x0 = sin(2*pi*100MHz*t). If I have sign(x0) (or alternatively Zero-Order-Hold with 2 samples per period) then I ge...


PID controller in a robotic sailboat

Started by Scott Hemphill in comp.dsp2 months ago 1 reply

I'm a long time lurker, here because occasionally the math is interesting. But recently, I got a chance to do some embedded programming. I...

I'm a long time lurker, here because occasionally the math is interesting. But recently, I got a chance to do some embedded programming. I thank Tim Wescott for his intro to PID controllers. I'll get to that bit, but first there's some background material. There's a program at Community Boating in Boston, Mass. which since at least 2013 has let high school students design software for con...


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