How to realize a RC LPF

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Anonymous
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Hello everyone,

   

          Dose anyone use the LPF component before?Why do i cannot find this component in Creator 2.2(the components have updated to 3.3)?Then,without this component ,how should i realize a arbitrarily RC LPF with the kit resource.Thanks.

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Roy_Liu
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 There is not a LPF filter component for PSoC3/5lp in Creator,  you may want to refer to the KBA(in below link) to realize a RC low pass filter.

   

http://www.cypress.com/?id=4&rID=38571

Roy Liu
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Anonymous
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Hi Roy,

   

if there is no LPF in the PSoC5, why are such blocks visible in the in the Family Datasheet for CY8C58LP (Doc Nr 001-84932 Rev. *I) and also in the PSoC Creator 3.3 Analog view? See attached pictures.

   

Best Regards /Oskar

   

         

   

   

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@Oskar

   

There is a digital filter in the psoc5 which you may use as LP filter.

   

 

   

Bob

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Anonymous
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Hi Bob,

   

Thanks for your answer. Unfortunately your answer does not answer my question since I was specifically referring to the LPF symbol in the block diagram. The digital filter is nice, but my signal is analog. Then just digitize the signal with an ADC? Well, that might require an anti-alias-/low-pass filter to avoid sampling distortion: I am back on square one. A simple on-chip analog low-pass filter would definitely have been useful.

   

Other ideas to solve this would be to get off-chip, do the filtering, then enter the chip again to the ADC, but it seems a bit inefficient. Yet another idea would be to do active low-pass filtering with one of the Op-Amps, but I would like to use these for other tasks.

   

Thanks,

   

Oskar

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YuxianL_01 ,

A LPF component now exists!

A LPF (Low-Pass Filter) Component -- Finally!!!

Len

Len
"Engineering is an Art. The Art of Compromise."
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Anonymous
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 @Liu,

   

Yeah,thanks a lot.May i have a question plus?Do you have the experience to creat a sine wave?Which solution?Maybe use the WaveDAC8,but i cannot find it in creator2.2.

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Bob_Marlowe
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We are at Creator 3.0, so the support for 2.x is rather small. The principle of WaveDAC8 was to generate a table and send its values out to the DAC using DMA at a given frequency. So this you can setup yourself. When the waveform is fixed for the implementation, you may pre-calculate the sampling-points in advance and enter them into a table in flash manually. This way I created a 3-phase sin output.

   

 

   

Bob

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Anonymous
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 @Bob,

   

So it's maybe caused by the version of the software ,isn't it?Thanks Bob.

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Bob_Marlowe
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Additionally you may follow this thread http://www.cypress.com/?app=forum&id=2233&rID=63395 to implement a filter intrinsic to PSoC5

   

 

   

Bob

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Anonymous
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If you are not aware of the WaveDac component before, you can download the same from here - www.cypress.com/

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Anonymous
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ETRO_SSN583
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There are many ways to create a sinewave, here is a thread

   

of several approaches, easilty adaptable  to any PSOC.

   

 

   

    

   

          http://www.cypress.com/?app=forum&id=4749&rID=87592

   

 

   

And you can always Add Wavedac component to your 2.2 library.

   

 

   

You can also use non linear shaping, like diode like FET transfer square law Vgs

   

to Id relationship, simple square wave into BP filter to extract findamental, Vbe

   

waveshaping, PWM generated sine......................

   

 

   

Regards, Dana.

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ETRO_SSN583
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Forgot simple Wein Bridge using OpAmp and handlul RCs,

   

very low distortion, OpAmp and RC ladder, State Variable.....

   

 

   

Many many methods with varying distortion and performance

   

and amount of HW needed.

   

 

   

Regrads, Dana.

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Anonymous
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 @danaaknight,

   

yeah,very thanks for your answer.I have looked the link you send to me.You showed three methods to generate a sine .I am interested in the third one, how did you realize the RC filter?May be extern the kit?

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