## Forums comp.dsp

## Stability in PID Controllers

inI know next-to-nothing about this topic, but the following question has popped into my mind several times. It seems like folks generally (and...

I know next-to-nothing about this topic, but the following question has popped into my mind several times. It seems like folks generally (and perhaps this is totally wrong) design PID controllers by basically selecting what they think are "good" constants for the proportional, integral, and derivative terms. That is, they just sorta play with their systems and tweak the terms until it seem...

## Geometric Algebra

inI think this set of 6 introductory videos on geometric algebra is neat. https://youtu.be/srwoPQfWWS8?list=PLLvlxwbzkr7igd6bL7959WWE7XInCCevt

I think this set of 6 introductory videos on geometric algebra is neat. https://youtu.be/srwoPQfWWS8?list=PLLvlxwbzkr7igd6bL7959WWE7XInCCevt

## Recreating Undersampled Data

inI've got a situation coming up that I'm trying to think through in advance. I'm running an ADC at let's say 1 Msps, sampling an input waveform...

I've got a situation coming up that I'm trying to think through in advance. I'm running an ADC at let's say 1 Msps, sampling an input waveform that is known to be a triangle wave at roughly 2 1/16 MHz. So with every ADC sample I advance across the input waveform by about 22.5 degrees, having missed a bit along the way. And I acquire that data and now I'm looking at it offline, and I'd...

## How to downsample this signal?

inHello, I have the 50Hz mains voltage signal sampled at 12bit/100kHz. This high frequency is for rapid detection of overvoltage conditions....

Hello, I have the 50Hz mains voltage signal sampled at 12bit/100kHz. This high frequency is for rapid detection of overvoltage conditions. However, for further processing this sample rate is way too high, so I'd like to change the sampling rate by a factor ~100 (not a very critical value, just "sensibly low"). The thing will be implemented on a PSOC5LP, which has a dedicated digital fi...

## Need resources to implement WIFI on USRP devices.

Hi, Iam Eshwar. I realized 16qam,DSSS, FH based radios on USRP.Now i want to implement complete wifi on usrp. I need some resources on...

Hi, Iam Eshwar. I realized 16qam,DSSS, FH based radios on USRP.Now i want to implement complete wifi on usrp. I need some resources on standards (frame formats,modulation schemes,channel coding ..etc). I went through 802.11g standards.Iam confused on where to start with. Requirement : I will use USRP with laptop_1(connected to internet) on oneside and other side i will use...

## Matlab code needed for SSB demodulation

inHi Guys, I'm trying to help someone understand the operation of a discrete single-sideband (SSB) demodulation system that is being...

Hi Guys, I'm trying to help someone understand the operation of a discrete single-sideband (SSB) demodulation system that is being proposed to replace an older analog SSB demodulation system. Having not thought about SSB systems for many years, I've been trying to figure out how the "phasing method" of SSB demodulation works. In trying to model this "phasing method" using Matla...

## Good references on ultrasound beamforming and imaging

inHi everyone I hope this is the right group since I'm interested in the signal processing aspect mote than the physics itself. I'm trying to...

Hi everyone I hope this is the right group since I'm interested in the signal processing aspect mote than the physics itself. I'm trying to look for good references (either books or papers) that go over some ultrasound imaging and beamforming algorithms. Basically, things like delay and sum, dynamic focusing, adaptive beamforming, etc. Hopefully, it would also include ultrasound ima

## Generalized Cross Product

inI have a pair of N-dimensional vectors, N large (hundreds), and I need to generate another N-dimensional vector that is orthogonal to the first...

I have a pair of N-dimensional vectors, N large (hundreds), and I need to generate another N-dimensional vector that is orthogonal to the first two. It doesn't have to be unique; it doesn't even have to be perfectly orthogonal, as long as the normalized dot products are less than, oh, about 0.005. I've searched for "generalized cross product" and similar terms, and all I found was a

## Shannon and Sphere Hardening

inSo, I'm toying with Shannon's capacity theorem, trying to graph out the "sphere hardening" effect that he cites as the basis of the...

So, I'm toying with Shannon's capacity theorem, trying to graph out the "sphere hardening" effect that he cites as the basis of the principle. I can see, intuitively, how the whole notion that the volume of a sphere is concentrated in a thin shell works, but when I try to calculate actual numbers I start running into numerical difficulties at dimensions of around 150 or 200. Even wit...

## OT: Flash Memory

inGentle comp.dsp People, I've been involved on several projects over the past few years that utilize flash memory in microSD form, and several...

Gentle comp.dsp People, I've been involved on several projects over the past few years that utilize flash memory in microSD form, and several times they have inquired about problems with lifetime of such cards. My employer recently tasked me with investigating the alleged write lifetime issue. Frankly I was appalled at the numerous, significant issues I found in current-day cards. Doe...

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