<< Chapter < Page Chapter >> Page >

Approach

Flow chart for approach of range

Range analysis block diagram

Range Analysis Block Diagram

Chirp and chirp train design

First, we design a Linear Frequency Modulated (LFM) chirp for the desired time-bandwidth product amount (TW), oversampling amount p, and sampling frequency (fs) . The MATLAB program" dchirp2 "will build up a single pulse while" ctbuild4 "will design a burst waveform consisting of L chirps, repeated over a period M.

Example of"Dchirp2"Matlab function call

[s,h,y,T,W,Ts] = dchirp2(TW,p,sampfreq) with outputs:
  • s = single LFM chirp set to specified input paramters
  • h = match filter impulse response
  • y = (used for testing of original code) passing s through match filter
  • T = time duration of LFM chirp (units: sec)
  • W= swept bandwidth of LFM chirp (units: Hz)
  • Ts= sampling period (1/fs)

Example of"Ctbuild4"Matlab function call

[s,ssent,h,y,T,W,Ts] = ctbuild4(TW,p,sampfreq,M,L) with outputs:
  • s = single chirp defined by TW,p
  • ssent = noise-free burst waveform of L lfm chirps of the same TW, p
  • h = match filter impulse response
  • y = (used for testing of original code) passing s through match filter
  • T = time duration of LFM chirp (units: sec)
  • W= swept bandwidth of LFM chirp (units: Hz)
  • Ts= sampling period (1/fs)

Simulate radar returns

In order to simulate proper radar returns, we first simulate the noise of a channel. Thus, we add complex white Gaussian nosie, using the"crandn"command in MATLAB, to our complex train of chirps. We perform this opertion in our main MATLAB function called" burst4 ."Next, we then apply a time delay to our signal. The program accomplishes that by shifting a vector x of length N to the right by amount TD.
For the project we worked only with an assumed value of SNR = -10 dB (i.e. the std. deviation is the square root of 10 multiplied against the chirp's average amplitude). We did a visual comparison of these two values to make sure our value of n was correct. See MATLAB function" burst4 "for detailed commentary.
The TD value inputted by the user is in terms of how many elements the user wants to physically shift the transmitted wave form by and do not correspond to actual units of time.

Defining max range of radar processing

The Maximum Range of our radar system is determiend by two things. First, how large the resting time is between consecutive falling and rising edges of chirps. Secondly, how long our signal is. The reason why these are important is that since this model for range processing is in discrete time, we can not simulate an infinite range for our targets. That would correspond to having to time delay our transmitted signal by a extremely large amount. If shifted by an amount greater than the signal's length, the simulated return would just be a flat line of value zero for the length of the signal. Basically, the signal can be time delayed only up until the first LFM chirp's falling edge. This location corresponds to the last value of the recieved signal to ensure getting a big enough spike in the match filter's output to use in calculating range. Thus, since we define the value for time period (Ts) of our chirp pulse train and the number of pulses, we can define the max range by finding the maximum amount we can shift our signal. Then by plugging in this max Td value into the discrete-time range equation below, the max range value is found.

Equation for max time delay

MaxTD M L M N

Questions & Answers

Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Berger describes sociologists as concerned with
Mueller Reply
Got questions? Join the online conversation and get instant answers!
QuizOver.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Ece 301 projects fall 2003. OpenStax CNX. Jan 22, 2004 Download for free at http://cnx.org/content/col10223/1.5
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Ece 301 projects fall 2003' conversation and receive update notifications?

Ask