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Analog Low Pass Filter | Cypress Semiconductor

Analog Low Pass Filter

Summary: 12 Replies, Latest post by Gautam Das on 11 Oct 2012 12:52 AM PDT
Verified Answers: 0
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szhz's picture
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6 posts

 Can Filter in PSoC process the analog signal? I didn't see any I/O ports of Filter.

The example project of Filter used DMA to transfer the digital signal. Is DMA necessary for using Filter?

 

Regards

Yudong

user_1377889's picture
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10803 posts

The filter component in PSoC3/5 is digital in nature, thus requiring an ADC first. To remove the burden for the CPU to transfer the converted values from ADC to Filter a DMA is appropiare thus freeing a lot of MIPS.

Nevertheless there are two LPFs within a PSoC3/5 which you may use, have a look at this thread http://www.cypress.com/?app=forum&id=2233&rID=63395 

 

Bob

user_14586677's picture
User
7648 posts

DMA is just one option for the filter data handling -

General Description

The customizer for the Filter component allows you to configure digital filters on
one or two data streams passed to the Digital Filter Block(DFB),using DMA,interrupts,
or polling to manage data flow. TheDFB’s 128 data and coefficientlocations are shared
as needed between the two filter channels.The customizer reports (but does not set)
the minimum bus clock frequency required to execute the filtering within the user-
declared sample interval.

 

The filter can perform BP, LP, HP, Band Stop.......

 

Regards, Dana.

szhz's picture
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6 posts

 Hi Bob and Dana,

I have read the example project of Filter. In that project, the cutoff frequency is 1KHz and input voltage range of ADC is 0 to 1.024V. My input sine wave is 900Hz and Vpp = 1V. So I expect to get sine wave on output terminal of VDAC which is equal in amplitude and frequency to the sine wave on input terminal of ADC. But my wave observed is not like the expection. Have I made any mistakes?

 

Regards

Yudong

szhz's picture
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6 posts

  I attached my project.

szhz's picture
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6 posts
szhz's picture
User
6 posts

 I tried several times but failed to upload my files. My project is just the example project found in PSoC Creator.

Stub for 244090886's picture
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1 post

Have you zip the file?

szhz's picture
User
6 posts

 Yes, I zipped the file.

Try again.

user_1377889's picture
User
10803 posts

To upload a project here in Creator

Build -> Clean Project

File -> Create Workspace Bundle (minimal)

and then upload the resulting archieve here.

 

You do not get the signal you expect? A probabil might be that your 1V p-p signal might go below 0V. Check that with an oscilloscope.

 

Bob

user_1377889's picture
User
10803 posts

When uploading does not work, try to use MS Internet Explorer, I've seen some issues with other browsers.

 

Bob

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