<< Chapter < Page Chapter >> Page >

Line 31 branches back to the top, where we wait for the next block to arrive and start over.

Using test vectors

A second version of the core file offers the same interface as the standard core file, but instead of reading inputsamples from the A/D converters on the six-channel board and sending output samples to the D/A converters, it reads andwrites from test vectors generated in MATLAB.

Test vectors provide a method for testing your code with known input. Given this known input and the specificationsof the system, we can use simulations to determine the expected output of the system. We can then compare theexpected output with the measured output of the system. If the system is functioning properly, the expected output andmeasured output should match

Will the expected output and the actual output from the DSP systemmatch perfectly? Why or why not?

Testing your system with test vectors may seem silly in some cases, because you can see if simple filters work by lookingat the output on the oscilloscope as you change the input frequency. However, they become more useful as you writemore complicated code. With more complicated DSP algorithms, testing becomes more difficult; when you correct an errorthat results in one case not working, you may introduce an error that causes another case to work improperly. This maynot be immediately visible if you simply look at the oscilloscope and function generator; the oscilloscope doesnot display the signal continuously and transient errors may be hidden. In addition, it is easy to forget to check allpossible input frequencies by sweeping the function generator after making a change.

More importantly, the test vectors also allow you to test signals that cannot be generated or displayed with theoscilloscope and function generator. One important signal that cannot be generated or tested with the functiongenerator and oscilloscope is the impulse function; there is no way to view the impulse response of a filter directlywithout using test vectors. The unit impulse represents a particularly good test vector because it is easy to comparethe actual impulse response of a digital filter against the expected impulse response. Testing using the impulseresponse also exposes the entire range of digital frequencies, unlike testing using periodic waveformsgenerated by the function generator.

Lastly, testing using test vectors allows us to isolate the DSP from the analog input and output section. This is usefulbecause the analog sections have some limitations, including imperfect anti-aliasing and anti-imaging filters. Testingusing test vectors allows us to ensure that what we see is due only to the digital signal processing system, and notimperfections in the analog signal or electronics.

After generating a test vector in MATLAB, save it to a file that can be brought into your code using the MATLAB command save_test_vector (available as save_test_vector.m ):

>> save_test_vector('testvect.asm',ch1_in,ch2_in); % Save test vector

(where ch1_in and ch2_in are the input test vectors for input channel 1 and input channel 2; ch2_in can be omitted, in which case both channels of the test-vector input will have the same data.)

Next, modify your code to include the test-vector support code and the test-vector file you have created. This can bedone by replacing the first line of the file (which is a linker directive to copy in core.asm ) with two lines. Instead of:

.copy "core.asm"


.copy "testvect.asm" .copy "vectcore.asm"

Note that, as usual, the whitespace in front of the .copy directive is required. ( Download vectcore.asm into your work directory if you do not already have a copy.)

The test vectors occupy the .etext section of program memory between 08000h and 0FEFFh . If you do not use this section, it will not interfere with your program code or data. This memoryblock is large enough to hold a test vector of up to 4,000 elements. Both channels of input, and all six channels ofoutput, are stored in each test vector element.

Now assemble and load the file, and reset and run as usual. After a few seconds, halt the DSP (using the Halt commandunder the Debug window) and verify that the DSP has halted at a branch statement that branches to itself: spin b spin .

Next, the test vector should be saved and loaded back into MATLAB. This is done by saving 6 k memory elements (where k is the length of the test vector in samples, and the 6 corresponds to the six output channels) starting withlocation 08000h in program memory. Do this by choosing File->Data->Save... in Code Composer, then entering the filename output.dat and pressing Enter . Next, enter 0x8000 in the Address field of the dialog box that appears, 6 k in the Length field, and choosing "Program" from the drop-down menu next to "Page." (Always ensure that youuse the correct length - six times the length of the test vector - when you save your results.)

Last, use the read_vector function (available as read_vector.m ) to read the saved test vector output into MATLAB. Do thisusing the following MATLAB command:

>> [ch1, ch2, ch3, ch4, ch5, ch6] = read_vector('output.dat');

The MATLAB vectors ch1 through ch6 now contain the output of your program code in response to the input from the test vector.

Questions & Answers

find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
I know this work
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
hmm well what is the answer
how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
is it a question of log
I rally confuse this number And equations too I need exactly help
But this is not salma it's Faiza live in lousvile Ky I garbage this so I am going collage with JCTC that the of the collage thank you my friends
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris 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
what is nano technology
Sravani Reply
what is system testing?
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
what is system testing
what is the application of nanotechnology?
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
anybody can imagine what will be happen after 100 years from now in nano tech world
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
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele 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
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, Dsp laboratory with ti tms320c54x. OpenStax CNX. Jan 22, 2004 Download for free at http://cnx.org/content/col10078/1.2
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Dsp laboratory with ti tms320c54x' conversation and receive update notifications?