# 0.3 Iir filtering using the dsp56002

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This module introduces the design and implementation of IIR filters on the 56002.

## Iir filter implementation

The program iir.asm implements a real-time IIR lowpass filter ; the ADC procedure is the same as used for the FIR filter in FIR Filtering . The example IIR filter is found in El-Sharkawy Appendix F, Section 6 . Assemble, link, load and execute this routine; observe the frequency response passband edge frequency using asinewave input to the EVM.

Consider the seven instructions in iir.asm ( shown below ) that implement cascaded second order sections of the IIR filter. For a single section nsec=1 use the flow diagram in and a sequence of diagrams as in to explain the execution of a single biquad section. Express the value of the accumulator at each step interms of $x(n)$ , $w(n)$ , and $y(n)$ .

mpy y0,y1,a x:(r0)+,x0 y:(r4)+,y0 do #nsec,_ends mac x0,y0,a x:(r0)-,x1 y:(r4)+,y0 macr x1,y0,a x1,x:(r0)+ y:(r4)+,y0 mac x0,y0,a a,x:(r0) y:(r4)+,y0 mac x1,y0,a x:(r0)+,x0 y:(r4)+,y0 mac x0,y0,a x:(r0)+,x0 y:(r4)+,y0 _ends

## Filter design

A speech signal has been recorded in the presence of a loud, annoying, high frequency hum. Measurements have indicatedthat the noise energy is isolated to frequencies in the range of 2850Hz to 2950Hz. Use Matlab to design an IIR notch filter to remove these unwanted components. Design the filter for a sampling rate of 16kHz; set the DSP sampling rate to 16kHz in the file ada_init.asm . Implement this filter on the 56002 and verify its operationusing the oscilloscope and speakers. Compare the computational cost of your IIR filter on the 56002 to the FIRdesign from the FIR Filtering Lab .

## Matlab suggestions

Use either Butterworth or Elliptic designs with a 'stop' bandreject option. Try a 60dB stopband attenuation as a starting point. Be careful with signs on denominator coefficients. Yourreport should comment on your design choices. Plot both magnitude and phase responses. The reject band can beplotted using these commands:

[h,w]=freqz(b,a,1024); hold off; plot(w*8000/pi,20*log10(abs(h))); axis([2400 3400 -80 0]); grid; hold on; plot([2850 2850],[0 -80],'r'); plot([2950 2950],[0 -80],'r'); xlabel('frequency, Hz'); ylabel('magnitude response, dB');

## Saving cycles

Modify your program to avoid the reset of r0 and r1 inside the filtering loop in iir.asm . See Page 165 of El-Sharkawy for comments on modulo addressing and the dsm assembler directive.

## Interrupts versus polling

Rewrite your program to implement filtering using interrupts , in contrast to the polling used in iir.asm . The routines within txrx_isr.asm can be modified for this purpose. The main loop of your program should count thenumber of free cycles remaining per sampling period. Use the A accumulator to count the number of cycles not used inimplementing the IIR filter. Store and reset the accumulator value as part of your interrupt routine.

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what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
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da
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Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
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Application of nanotechnology in medicine
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I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
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Rafiq
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Damian
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LITNING
scanning tunneling microscope
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Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
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Mahi
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Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
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