# Search results

1. ### How to measure output voltage of B200?

Hi, I am a new student and trying to to measure the power and voltage output from B200 SDR device (https://www.ettus.com/content/files/b200-b210_spec_sheet.pdf) using oscilloscope (TDS3000 Series: https://www.atecorp.com/ATECorp/media/pdfs/data-sheets/Tektronix-TDS3000_Series_Manual.pdf)...
2. ### MATLAB Why 2 vectors are not the same in matlab?

@Mark44: that could be, i am happy if some very small decimal number exist (my expectation in nano or pico values) but is there any way to detect them (if they are exist), even I used command format long and still do not see any change.
3. ### MATLAB Why 2 vectors are not the same in matlab?

@berkeman: if I shift right by 4 places instead of using the multiplication, I will have what I want, that is vector [1 1 1 1], that is no surprise, but the thing I am working on is very small number (in nano values 1e-9) and sometime matlab gives me a vector, example: a = 1.0e-04*[ 1 1 1 1]...
4. ### MATLAB Why 2 vectors are not the same in matlab?

I have 2 vectors: a = 1.0e-04*[0.110000000000000 0.140000000000000 0.140000000000000 0.140000000000000]; b = [0.000011000000000 0.000014000000000 0.000014000000000 0.000014000000000]; by look at by eyes, it seems similar; but when I use this command: a == b then I got...
5. ### How to add confg file to allow UHD drive set priority?

I have Ettus B210 and trying to add 1 line configuration file "/etc/security/limits.conf" which will allow UHD drive to set priority. So , I typed this command to edit file: gksudo gedit /etc/security/limits.conf and add: #@student hard nproc 20 #@faculty soft...
6. ### What is preventing me from achieving better accuracy for this delay?

Did I do right? make sense to you? please fix me! https://www.dropbox.com/s/le4ppw32l4sp5ll/RX1.dat?... https://www.dropbox.com/s/zr04pff9skeh8cn/TX.dat?d... clear all; close all; format long; %% initial values: nsamps = inf; nstart = 0; Fs = 8e6; % sample rate 8MHz...
7. ### What is preventing me from achieving better accuracy for this delay?

I am not sure, but what if they are analog signal? and what if they are digital signal? I also have an image which show the relationship of them.
8. ### What is preventing me from achieving better accuracy for this delay?

Yes, I do. I did wrong. I fixed it.
9. ### What is preventing me from achieving better accuracy for this delay?

@FactChecker: yes, I am using the rubidium clock the time synchronized by interrupt (http://www.thinksrs.com/products/PRS10.htm) and 1 set on the TX and another on set on the RX. the accuracy of it is 5e-11s
10. ### What is preventing me from achieving better accuracy for this delay?

@f95toli: index i means, I calculate delay in multiple RX signal from the receiver (not only one), I want to see the variation of the delay.
11. ### What is preventing me from achieving better accuracy for this delay?

they are not the same value, because of noise added due to signal bouncing in the lab, the amplitude of the TX data bigger than RX data 30 times. original length of TX data is about 208000, but the length of RX data is 800000, therefore after the Transmitted real TX data, and the rest of time in...
12. ### What is preventing me from achieving better accuracy for this delay?

@FactChecker: Sorry for lacking of knowledge, but I thought the calculations were wrong. you also helped me know more the way to debug the problem. I appreciated for it. Consider I have this question "how much accuracy you have in the timing?" as you mentioned. Fix me if I state: "an...
13. ### What is preventing me from achieving better accuracy for this delay?

@FactChecker: very helpful, even I am still trying to understand the meaning of MAXLAG. but 1 thing I also thinking of, that is: the professor is asking to find the interpolated maximum of xcorr rather than max sample location. So, the continuous signal is difference from computed sample peak...
14. ### What is preventing me from achieving better accuracy for this delay?

I just discussed with the professor, he also mentioned the expectation for the delay will be 3ns or better (less than 1m). I do not have continue function, I jsut have function of the sample time (sample waveform different to the continuous of time waveform) I am taking sample number of delay...
15. ### What is preventing me from achieving better accuracy for this delay?

Yes, I did. I already tried with 1 second of data, and still give me the same delay in microsecond, I know the algorithm which I posted, was wrong and I am still trying to figure out the way to get in nanosecond. According to this link which I am following...
16. ### What is preventing me from achieving better accuracy for this delay?

So, Could you give me some suggestions how to fix it to make more sense? Let me explain what I am trying to do? I have a transmitted waveform and send to the RX device, such as TXdata.jpg and TXdata_vs_RXdata.jpg so I want to calculate the time delay with expectation is few nanoseconds. I also...
17. ### What is preventing me from achieving better accuracy for this delay?

@FactChecker: thank you the reply, I will review first four suggestions from you. and the 5th one I am trying to explain to you: I have 2 signal, 1 for the TX signal and 1 for the RX signal. The TX signal is sent from the transmitter have the waveform lTXdata.jpg and sent repeatly in 100...
18. ### What is preventing me from achieving better accuracy for this delay?

I have 2 PERFECT data of the transmitter and receiver. From 2 data, I can calculate the delay estimation: Fs = 8e6; % sample rate ... for i = 1:2 [cc_correlation,lag] = xcorr(signal2(i), signal1); [cc_maximum, cc_time] = max(abs(cc_correlation)); cc_estimation...
19. ### How to calculate standard deviation?

are you still there?
20. ### How to calculate standard deviation?

I also attached this function readcplx below, it works for .dat file, have you tried it? if you tried it and did not work, i will send you the the excel format, because these are long data in complex. it will take time to convert into excel format.

22. ### How to calculate standard deviation?

I have 2 signals: signal1: https://www.dropbox.com/s/zr04pff9skeh8cn/TX.dat?dl=0 signal2: https://www.dropbox.com/s/h436a915dd99hln/RX1.dat?dl=0 signal2 represents for 20 measurements, each measurement combines with signal1 to get time delay estimation using xcorr. So, I will have 20 delays...
23. ### What do electric and magnetic fields look like around a dipole antenna?

It is helped, but for the visualization. Do you have any information (links, or book) in detail for this topic? if I have 2 same antennas, 1 is right next to me and another is 6km away what direction do I expect for the electric field to be in distance d? and what do you expect to see the one...
24. ### What do electric and magnetic fields look like around a dipole antenna?

I am studying to about maxwell's equations on the electric and magnetic field. First of all, just do the example and exercise: https://www.princeton.edu/ssp/josep...ide-to-maxwells-equations-D.-FleischLEISC.pdf [Broken] I have this dipole antenna...
25. ### How to measure time variation of 2 signals using an oscilloscope?

I just want to confirm again that the time variation measurement is the similar of "delay" function on the scope, right?
26. ### How to measure time variation of 2 signals using an oscilloscope?

@analogdesign : so, If I want to trigger 1 of those signal, I just need to choose "CH1" (yellow button) and press "B TRIG" button?
27. ### How to measure time variation of 2 signals using an oscilloscope?

I have 2 rubidium clocks which both are generating 10MHz sine wave. Some reason my system is giving bad data. So, I am deciding to inspect every single part of the system. I am trying to check the rubidium clock and make sure it have to be in nanosecond time variation, because: t=1/f = 1/10e6 =...