## Forums

## The $10000 Hi-Fi

How much does it really matter that you get a decent DAC? This is all about jitter but do we all notice the difference or just a few people with...

How much does it really matter that you get a decent DAC? This is all about jitter but do we all notice the difference or just a few people with golden-ears?

## BER for QPSK in OFDM over Multipath Channel

inHi, I need a help please and an answer for this: I'm trying to do a BER simulation for QPSK in OFDM system over a Multipath Channel in Matlab...

Hi, I need a help please and an answer for this: I'm trying to do a BER simulation for QPSK in OFDM system over a Multipath Channel in Matlab and I'm using the function (ht=rayleighchan()) for model the multipath channel with the following parameters: tau=[0 1e-4 2e-4] second %Path Delay Ts=1e-5 sec or 1e-3 sec(for another simulation) %Sample Period Fd=0; %...

## LMS algorithm in fixed point arithmetic

inI have been coding a very rudimentary LMS algorithm for Echo cancellation but I am stuck since the code is not working. I have kept the code to...

I have been coding a very rudimentary LMS algorithm for Echo cancellation but I am stuck since the code is not working. I have kept the code to be very simple and yet I am not able to identify where the code is going wrong. Please help me to identify the error in the code. FILE *ref; and FILE *des; contains the same data and ideally when the algorithm converges,there should not be any voi...

## Check this pulse ox signal out

inI've shared a screenshot of the pulse ox signal I'm acquiring from the ADC on a device. There's also another diagram which illustrates the test...

I've shared a screenshot of the pulse ox signal I'm acquiring from the ADC on a device. There's also another diagram which illustrates the test setup. http://dropcanvas.com/f2w7d I ran this test to document a fundamental flaw in the design, but I'm curious to hear if the seasoned HW/SW engineers in this group agree that there's a problem. This is the test I ran: 1. Place mirro

## noise reduction with long fft's

inThere's a statement in Smiths The Scientist and Engineer's Guide to Digital Signal Processing about the effect of fft length on noise. In arguing...

There's a statement in Smiths The Scientist and Engineer's Guide to Digital Signal Processing about the effect of fft length on noise. In arguing the virtues of averaging multiple short fft's instead of one long fft he says "Longer DFTs provide better frequency resolution, but the same noise level." But thats not true is it? The noise level of an fft rises with the sqrt(N). The signal grows wit...

## fast, say O(log2(N)), sliding median algorithm

ini also posted this to the programmers stack exchange. but comp.dsp peeps seem to know alot about stuff that's broader than DSP. so i know...

i also posted this to the programmers stack exchange. but comp.dsp peeps seem to know alot about stuff that's broader than DSP. so i know how to do a fast O(log2(N)) sliding max or sliding min algorithm. Brookes: "Algorithms for Max and Min Filters with Improved Worst-Case Performance" IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS?II: ANALOG AND DIGITAL SIGNAL PROCESSING, VOL. 47, NO. 9...

## Help me prove/disprove this trig conjecture

inOK. This is probably stupid. For n even, the sum from k = 1 to k = n of cos(2 * pi * k/n + phi) is zero, almost by inspection. (Divide k up...

OK. This is probably stupid. For n even, the sum from k = 1 to k = n of cos(2 * pi * k/n + phi) is zero, almost by inspection. (Divide k up into the 1 to 1/n part and the other part -- every cos(etc) in the first part has a cos(etc + pi) in the second part. Cancel, done). I'm almost certain that this is true for n odd. Anyone know for sure? Have a reference and/or easy proof? O...

## How to decide FFT window size in OFDM system receiver

inCould someone please explain me in details how we select the FFT window size at the receiver of the OFDM system? Does it include both the size...

Could someone please explain me in details how we select the FFT window size at the receiver of the OFDM system? Does it include both the size of N parallel sub carriers and the Cyclic Prefix length? Thanks! _____________________________ Posted through www.DSPRelated.com

## predictive first order hold (another IEEE paper request)

ini know i've asked this of my IEEE bros here, but if someone has access to old IEEE papers (with no additional cost to them), would you be so...

i know i've asked this of my IEEE bros here, but if someone has access to old IEEE papers (with no additional cost to them), would you be so kind to get me a .pdf copy of this: Bernhardsson, "The predictive first order hold circuit", Proceedings of the 29th IEEE Conference on Decision and Control, 1990. ? http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=203948 it's more ...

## Shameless plug -- control systems talk in San Jose, September 14th-18th

inIn case anyone has been dying to attend one of my talks (or send an associate), I'm now hooked up with a company that presents seminars. ...

In case anyone has been dying to attend one of my talks (or send an associate), I'm now hooked up with a company that presents seminars. Basically, they do all the work that I absolutely dreaded doing to put my seminars on a firm business footing, and I just do the stuff that I do really well. I know this is self-promotion, but I've been contributing to all three of the groups I'm cr...