What is the difference between "phased.LinearFMWaveform" and "phased.FMCWWaveform"
4 views (last 30 days)
Show older comments
1. What is the difference between "phased.LinearFMWaveform" and "phased.FMCWWaveform" in Phased Array System Toolbox except for that Triangle waveform generation is possible in P"phased.LinearFMWaveform" function.
2. My other concern is I want to sweep bandwidth of 10Mhz from start frequency of 10 MHz and End Frequency 20MHz. How can i do that in "phased.LinearFMWaveform" function.
3. When i dechirp the received signal from transmitted signal of saw-tooth waveform, i should get 2 beat frequencies (according to "New ideas in FM Radar by H. D. Griffiths"). but i get only 1 beat frequency, why?
0 Comments
Accepted Answer
Honglei Chen
on 27 Dec 2012
Hi Ali,
LinearFMWaveform is a pulse waveform, meaning that in general the system only transmit a very short period of time during one cycle and uses the rest of cycle to receive. On the other hand, FMCWWaveform is a continuous waveform, so the system transmits and receives at the same time and the duty cycle for the waveform is always 1.
Currently you cannot specify the starting and ending frequencies in LinearFMWaveform. However, depending on the system setup, you may still be able to simulate your case. For example, if your system's center frequency is 15 MHz, then your situation is just a symmetric sweeping over a 10MHz range.
I don't have that particular paper handy so I cannot comment much on your third question without seeing some code snippet.
HTH
4 Comments
More Answers (1)
Nadir HEFHAF
on 10 Sep 2017
Edited: Honglei Chen
on 11 Sep 2017
i have problem also in this program
close all
clc
clear all
L = 50;
N = 4;
rxULA = phased.ULA('Element',phased.OmnidirectionalMicrophoneElement,...
'NumElements',N);
rxpos1 = [0;0;0];
rxvel1 = [0;0;0];
rxax1 = azelaxes(90,0);
rxpos2 = [L;0;0];
rxvel2 = [0;0;0];
rxax2 = rxax1;
srcpos = [30;100;0];
srcvel = [0;0;0];
srcax = azelaxes(-90,0);
srcULA = phased.OmnidirectionalMicrophoneElement;
fc = 300e3; % 300 kHz
c = 1500; % 1500 m/s
dmax = 150; % 150 m
pri = (2*dmax)/c;
prf = 1/pri;
bw = 100.0e3; % 100 kHz
fs = 2*bw;
waveform = phased.LinearFMWaveform('SampleRate',fs,'SweepBandwidth',bw,...
'PRF',prf,'PulseWidth',pri/10);
signal = waveform();
nfft = 128;
radiator = phased.WidebandRadiator('Sensor',srcULA,...
'PropagationSpeed',c,'SampleRate',fs,...
'CarrierFrequency',fc,'NumSubbands',nfft);
collector1 = phased.WidebandCollector('Sensor',rxULA,...
'PropagationSpeed',c,'SampleRate',fs,...
'CarrierFrequency',fc,'NumSubbands',nfft);
collector2 = phased.WidebandCollector('Sensor',rxULA,...
'PropagationSpeed',c,'SampleRate',fs,...
'CarrierFrequency',fc,'NumSubbands',nfft);
channel1 = phased.WidebandFreeSpace('PropagationSpeed',c,...
'SampleRate',fs,'OperatingFrequency',fc,'NumSubbands',nfft);
channel2 = phased.WidebandFreeSpace('PropagationSpeed',c,...
'SampleRate',fs,'OperatingFrequency',fc,'NumSubbands',nfft);
[~,ang1t] = rangeangle(rxpos1,srcpos,srcax);
[~,ang2t] = rangeangle(rxpos2,srcpos,srcax);
sigt = radiator(signal,[ang1t ang2t]);
sigp1 = channel1(sigt(:,1),srcpos,rxpos1,srcvel,rxvel1);
sigp2 = channel2(sigt(:,2),srcpos,rxpos2,srcvel,rxvel2);
[~,ang1r] = rangeangle(srcpos,rxpos1,rxax1);
[~,ang2r] = rangeangle(srcpos,rxpos2,rxax2);
sigr1 = collector1(sigp1,ang1r);
sigr2 = collector2(sigp2,ang2r);
doa1 = phased.GCCEstimator('SensorArray',rxULA,'SampleRate',fs,...
'PropagationSpeed',c);
doa2 = phased.GCCEstimator('SensorArray',rxULA,'SampleRate',fs,...
'PropagationSpeed',c);
angest1 = doa1(sigr1);
angest2 = doa2(sigr2);
yest = L/(abs(tand(angest1)) + abs(tand(angest2)));
xest = yest*abs(tand(angest1));
zest = 0;
srcpos_est = [xest;yest;zest]
the problem is
Array formation and parentheses-style indexing with objects of class 'phased.LinearFMWaveform' is not allowed. Use objects of class 'phased.LinearFMWaveform' only as scalars or use a cell array.
Error in program11 (line 27) signal = waveform();
3 Comments
Harwanto Zidqi Putro
on 12 Aug 2020
Edited: Harwanto Zidqi Putro
on 12 Aug 2020
I have version 2016a, and its error with same problem
PATRICK UWIGIZE
on 30 Dec 2021
Edited: PATRICK UWIGIZE
on 30 Dec 2021
Upgrade you MATLAB to a newer version
See Also
Categories
Radar
Phased Array System Toolbox
Phased Array Design and Analysis
Antennas, Microphones, and Sonar Transducers
Show more
Find more on Linear Prediction in Help Center and File Exchange
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!