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Hi!
Can a positive tail pulse..amplitude no more than 5V and pulse duration maximum 50us (prf<= 1Mhz) be shaped to a gaussian near gaussian pulse using PSoC3?...Also like PSoC1 are the switched capacitor blocks available so that a simple CR-RC4 circuit can be realized?
Another thing...the block diagram of pulse oximeter on http://www.cypress.com/?rid=47829 shows an analog filter . I've not seen an analog filter in components of PSoC creator. How to find it?
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PSoC 3
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"Can a positive tail pulse..amplitude no more than 5V and pulse duration maximum 50us (prf<= 1Mhz) be shaped to a gaussian near gaussian pulse using PSoC3?..."
See comments below on last item
"Also like PSoC1 are the switched capacitor blocks available so that a simple CR-RC4 circuit can be realized?"
and take a look at this - www.cypress.com/
"Another thing...the block diagram of pulse oximeter on http://www.cypress.com/?rid=47829 shows an analog filter . I've not seen an analog filter in components of PSoC creator. How to find it?"
PSOC 3 has a digital filter block and DAC that can be used for general purpose filter. However your sampling rate
requirement of at least 2 Mhz (1 Mhz Nyquist preferably 10 Mhz Nyquist) cannot be done because there is
no fast SAR A/D to keep up wirth sampling rate. OpAmps could be used for filtering, but their GBW of 3 Mhz
too low to implement a meaningful repeatable filter at 1 Mhz.
Regards, Dana,
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Due to the central limit theorem, the Gaussian can be approximated by several runs of a very simple filter such as the moving average. The simple moving average corresponds to convolutionwith the constant B-spline ( a rectangular pulse ), and, for example, four iterations of a moving average yields a cubic B-spline as filter window which approximates the Gaussian quite well.
With pulse width of 50us, moving average filtering is doable, with 1mhz sampling ADC and DMA
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...and even the moving average can be done in hardware by using the UDBs programmed in Verilog and using a datapath could enforce the performance.
Bob
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The max sampling rate of Delsig, occuring at its lowest resolution, 8 bits, is 384K SPS,
16 bits at 48KSPS. PSOC 3 is limited to DelSig.
en.wikipedia.org/wiki/Gaussian_filter
The DFB block in PSOC 3/5 can be used to implement a FIR based Gaussian
approximation. Some design help can be found at -
www.mathworks.com/help/signal/examples/fir-gaussian-pulse-shaping-filter-design.html
Google "fir gaussian filter", there are a number of tools, some free, that can help
determining the coefficients for a FIR solution.
IIR approach - www.cwp.mines.edu/Meetings/Project06/cwp546.pdf
Regards, Dana.