# Search results

1. ### Calculating delay spread from Spectrum analyzer channel frequency response function

Hello to all guys, A bit of a help to my problem would be precious. Description: I use a pulse generator, a signal generator a mixer and an antenna to tranmit a pulse that is 400ns long, at 900MHz. I then use a spectrum analyzer to get the channel frequency response and the channel impulse...
2. ### Measuring the delay spread with a network analyzer.

Okay I am gonna write a part of matlab code that I use in order to get the impulse response from the ifft. % Gathering data -irrelevant with our result N = 1601; % Number of points K = importdata('D0-5ST1SPAN250.S1P',' '); freq1 = K.textdata(4:1604,1); real = K.textdata(4:1604,2); im =...
3. ### Measuring the delay spread with a network analyzer.

I found a mistake that I made. First of all, when I measured the received power I used a Frequency span of 600MHz and number of points(samples) equal to 1601(it is the maximum value on my VNA). I think that is more sensible to use a frequency span of 100MHz and 1601 number of points. Now, the...
4. ### Measuring the delay spread with a network analyzer.

Any help guys?
5. ### Measuring the delay spread with a network analyzer.

Yeah you are right FvM the instrument provides output power up to 10dBm. My mistake. Also, the measurements take place at an indoor lab with 4 walls, a ceiling and a floor so I think it should be ok. Above I have the impulse response from the newtowork analyzer. What should I do to find the...
6. ### Measuring the delay spread with a network analyzer.

How can I ensure that the antenna cofiguration actually involces multipath-transmission? Also, I can set the power to 30dBm to be sure that the other paths are strong enough. If I make sure that the two conditions above are valid then I can set the number of points to the highest point in my...
7. ### Measuring the delay spread with a network analyzer.

Hello to all, I would like some help from you in a project that I work now. I built two monopole antennas and I measured reflection coefficient of each one and the S21 for the received power. The two antennas operate at 900MHz. What I wanted to ask you is how I can find out the delay spread...
8. ### Antenna measurements with network analyzer. Help needed!

Pstuckey , thanks again. I found a solution to the problem that I had. Also, about the delay spread it is not able to measure it, since you can measure only the phase difference between the reference signal and the recceived one, so you can measure only a time delay that corresponds up to 360...
9. ### Antenna measurements with network analyzer. Help needed!

Thanks pstuckey! The network analyzer that I use has the following options. For port 1 has the option of A) Transmission and B) Reflection. The same is true for port 2. In order to get the S21 measurements I must set the port1 and port 2 to Transmission? or just port 2 to Transmission? What is...
10. ### Antenna measurements with network analyzer. Help needed!

Hello to all, I made two λ/4 monopole antennas with your precious help and now I need some guidance about the measurements. First of all, I calibrated the network analyzer(HP 8714C) with the open, short and load and I tuned the antennas in order to operate at 900 MHz. Also, I measured the...
11. ### Help with λ/4 monopole antenna.

Thanks guys! Your advices are great. Tons of knowledge here! Regards, Manos
12. ### Help with λ/4 monopole antenna.

Dave, I want to thank you for your advice too. One more question to you and enjunear. I have read that the are of the ground plane should be λ/4*λ/4. Why do you propose the PCB sheet to be 2Xλ/4? Is this for performance reasons? Thanks in advance, Manos ---------- Post added at 19:38...
13. ### Help with λ/4 monopole antenna.

First of all, thank you for your precious help. What I was thinking is that I will use a pcb laminate(with fiber glass) which will have copper sheet at the bottom side and there we will solder a right angle sma connector. I will connect to the connector a sma rf cable. Also, I will drill a hole...

15. ### Help with λ/4 monopole antenna.

Hello to all, I am working on a project for channel measurements in an indoor environment and my part of this project is to design and construt 2 quarter-wave monopoles for 2 different operating frequencies( one for 900MHz and the other for 2.4GHz). The antennas will be made with a PCB(which is...
16. ### Cooperative spectrum sensing(energy detection) in cognitive radio.Matlab code

Hello to all! It seems that i might need a little help with the matlab code in a cooperative spectrum sensing project. As you will see if you run the code the ROC figures for the theoretic part is correct but for the simulation part is not.Can somebody help me? clear all; close all; clc...
17. ### Path loss due to distance

Thank you very much!
18. ### Path loss due to distance

please some help on this. Assuming the distance between transmitter and recfceiver is d and the transmitted signal is y then the received power in the receiver using matlab is rec_pow=mean(y.^2)./(d.^4). Is this correct? We assume that the channel model is AWGN.Thank you very much.
19. ### Path loss due to distance

Hello to all of you. Im working on a project about cooperative spectrum sensing(cognitive radio) and i have a problem. I want to calculate the SNR (received power/power of noise) at each Cognitive Radio,but i dont know jow to calculate the received signal power(it must be dependent to the...