<< Chapter < Page Chapter >> Page >
You will implement a multirate system that includes three fininte impulse response filters. The sample-rate compression and expansion factors can be controlled in real time using a MATLAB graphical user interface.


Before implementing the entire system shown in Multirate Processing: Introduction , we recommend you design a system that consists of a cascade of filters FIR 1 and FIR 2 without thesample-rate compressor or expander. After verifying that the response of your two-filter system is correct, proceed toimplement the complete multirate system and verify its total response. At first, use fixed compression and expansionfactors of D U 4 . After you have verified that the multirate system works at a fixed rate, you should modify your code so that therate can be changed easily. Later, you have the option of controlling this factor in real-time using a MATLAB interface. Regardless of whether you choose to use the MATLAB interface, you must be able to quickly change the compression and expansionfactors when you demo your code .

Compressed-rate processing

In order to perform the processing at the lower sample rate, implement a counter in your code. Your counter willdetermine when the compressed-rate processing is to occur, and it can also be used to determine when to insert zerosinto FIR 3 to implement the sample-rate expander.

Some instructions that may be useful for implementing your multirate structure are the addm (add to memory) and bc (branch conditional) instructions. You may also find the banz (branch on auxiliary register not zero) and the b (branch) instruction useful.

Real-time rate change and matlab interface (optional)

A simple graphical user interface (GUI) is available (as mrategui.m , which requires ser_snd.m ) that sends a number between 1 and 10 to the DSP via the serial port. This canbe used to change the compression and expansion factor in real time.

Run the GUI by typing mrategui at the MATLAB prompt. A figure should automatically open up with a slideron it; adjusting the slider changes the compression and expansion factor sent to the DSP.

The assembly code for interacting with the serial port, provided in the handout Core File: Serial Port Communication Between MATLAB and TI TMS320C54x , stores the last number that the DSP has received from the computer in thememory location labeled hold . Therefore, unless you have changed the serial portion of the givencode, you can find the last compression and expansion factor set by the GUI in this location. You need to modify yourcode so that each time a new number is received on the serial port, the compression and expansion factor ischanged. If a "1" is received on the serial port, the entire system should run at the full rate; if a "10" isreceived, the system should discard nine samples between each sample processed at the lower rate.

Note that the READSER and WRITSER macros, which are used to read data from and send data to the serial port, overwrite AR0 , AR1 , AR2 , and AR3 registers, as well as BK and the condition flag TC . You must therefore ensure that these registers are not used by your code, or that you save andrestore their values in memory before you call the READSER and WRITSER macros. This can be done using the mvdm and mvmd instructions. The serial macros set up the AR1 and AR3 each time they are called, so there is no need to change these registers beforethe macros are called.

More detail about the READSER and WRITSER macros can be found in Core File: Serial Port Communication Between MATLAB and TI TMS320C54x .

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar 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
Berger describes sociologists as concerned with
Mueller Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Ece 320 spring 2004. OpenStax CNX. Aug 24, 2004 Download for free at http://cnx.org/content/col10225/1.12
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Ece 320 spring 2004' conversation and receive update notifications?