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PSoC 5, 3 & 1 MCU

Anonymous
Not applicable

 hello every one,

   

I want to know exactly what i have to put like a parameter in the Instrumentation amplifier to get a signal in the output .

   

i specify that i use a mesure of biceps muscle .

   

so please help me gays 

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1 Solution
Employee

First you have to know the size of your signal. ECG signals are in the range of 0.5 to 2.0 Vpp. EMG signals are ususally smaller.

   

Set your PGAs gain of 50. Don't use the differential to single ended converter. The system will work better if you go directly from the PGA outputs to the differential input of a 16 bit ADC_Delsig. You will almost certainly want to put two or three poles of passive filter on the inputs to set a band limit to a few hundred Hz. The pole locations should be carefully matched in order to preserve the common-mode rejection. At EMG frequencies (less than 100 Hz), the signal filtering (after the input filtering)  is best done in software, not analog hardware.

   

---- Dennis, PSoC Apps

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Anonymous
Not applicable
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Employee

First you have to know the size of your signal. ECG signals are in the range of 0.5 to 2.0 Vpp. EMG signals are ususally smaller.

   

Set your PGAs gain of 50. Don't use the differential to single ended converter. The system will work better if you go directly from the PGA outputs to the differential input of a 16 bit ADC_Delsig. You will almost certainly want to put two or three poles of passive filter on the inputs to set a band limit to a few hundred Hz. The pole locations should be carefully matched in order to preserve the common-mode rejection. At EMG frequencies (less than 100 Hz), the signal filtering (after the input filtering)  is best done in software, not analog hardware.

   

---- Dennis, PSoC Apps

View solution in original post

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Anonymous
Not applicable

 Thank you sir for your precious information i have an other question about a filter bloc i want to use a butterworth filter which the band pass is between [50____500] HZ .

   

i have a problem to use the Band pass filter in this scale,

   

i used the FIR filter but when i saw in the scope the 50 hz was not removed!!!!. i use 128 staps (max)

   

i want to have a different idéa about how can i implement this filter & how can i combine two filter (high pass & low pass ) to create band pass filter 

   

Regards,

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Esteemed Contributor II

Did you try settings like in the attached picture.

   

 

   

Bob

Anonymous
Not applicable

 Have you test this circuit Mr Marloe ??? 

   

thank you sir 

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Esteemed Contributor II

Not this configuration that I set up for you, but a couple of other filters and all of them work.

   

When your filter does not work as you expect, can you post your complete project, so that we all can have a look at all of your settings? To do so, use
Creator->File->Create Workspace Bundle (minimal)
and attach the resulting file.



Bob
 

Esteemed Contributor

You can try the filter by placing WaveDAC8 onto the schematic and generate the corner

   

frequencies and look at the filter output. Change its sample frequency to get the other

   

corner.

   

 

   

   

 

   

Regards, Dana.

   

 

   

Esteemed Contributor

If you want linear phase BiQuad may not be best solution, see phase

   

curve below -

   

 

   

Esteemed Contributor

An alternative is to use 2 OpAmps and do a 4'th order Sallen-Key (TI Filtrerpro,

   

free to download) -

   

 

   

   

 

   

 

   

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Employee

If your filter is from 50 Hz to 500 Hz, then by definition, 50 Hz is not removed. The standard filter spec is -3dB at the corner frequencies, so that with you 50-500 BPF, the signal at 50 Hz is attenuated by only 30%. What do you really need and what are you trying to get rid of? Have you considered a notch filter at 50 Hz? This is easily implemented in PSoC Creator.

   

---- Dennis

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Esteemed Contributor

Being EMG, heart rate, surely you want 50 beats/sec or even lower as part of the

   

range. As seg suggests maybe a notch to get rid of your 50 Hz power line problem,

   

or good CMR at the diff amp if thats the source, and a LPF.

   

 

   

Regards, Dana.

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Anonymous
Not applicable

 thank you for your answer ,

   

when i use the instrumentation amplifier with 3 op amp or (2 pga  and 1 op amp)   

   

and a gain of 1200  because the signal is near of 0.5 mv i see in the scope that i have square signal  and no emg signal was displayed

   

i use the 0.5 % of tolérance in the differantial op amp  with 28 gain and the PGA was at 50 both

   

so help me gays !!!! 

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Esteemed Contributor

You CANNOT use PGAs in a PSOC to do an IA (unless you do not care you have no

   

appreciable CMR) -

   

 

   

You will have to use external IA to accomplish CMR and signal path G.

   

 

   

 

   

http://www.cypress.com/?app=forum&id=2492&rID=82151     IA CMR Analysis

   

 

   

Regards, Dana.

   
     sbaa160a2.zip   
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Esteemed Contributor

This is also useful, attached.

   

 

   

Regards, Dana.

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Anonymous
Not applicable

 Thank you dana knight for your contribution and your precious information ,

   

Now i want to send the data by using the bluetooth module from the filtring bloc (ADC delsig + DMA + FILTER + VDAC

   

how I can proceed  ????

   

this is what I did 

   

Also in the programme i have integrate the UART and deleting the Vdac but what i received in the terminal different character when i plot them in the graphical interface i dindn't see the same signal that i have seen when i was using the Vdac .

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Anonymous
Not applicable
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Esteemed Contributor

Here is a thread discussing DMA out to a UART -

   

 

   

    

   

          https://secure.cypress.com/?app=forum&id=2233&rID=111484

   

 

   

Some general ap notes on DMA -

   

 

   

    

   

          

   

http://www.cypress.com/?rID=37793     AN52705     Getting Started with DMA

   

http://www.cypress.com/?rID=82680     AN84810     PSoC® 3 and PSoC 5LP Advanced DMA Topics

   

http://www.cypress.com/?rID=44335     AN61102 PSoC® 3 and PSoC 5LP - ADC Data Buffering Using DMA

   

http://video.cypress.com/video-library/search/dma/     Videos on DMA

   

https://www.youtube.com/results?search_query=dma+psoc Videos on DMA (some overlap)

   

 

   

 

   

Regards, Dana.

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