Thanks, It worked! Franco
On Mon, Jan 6, 2020 at 4:47 AM Adam Isaacson <[email protected]> wrote: > Hi Franco, > > I sent you an invite to join slack casper-astro.slack.com. I hope it > works. Let me know. > > Kind regards, > > Adam Isaacson > South African Radio Astronomy Observatory (SARAO) > Hardware Manager > Cell: (+27) 825639602 > Tel: (+27) 215067300 > email: [email protected] > > > > On Mon, Dec 30, 2019 at 8:30 PM Franco <[email protected]> wrote: > >> Hi Dan, >> >> I was unaware that the compiler was able to remove unused logic, that's >> pretty useful. >> What I need is one real input to one complex output, so I'll check Nitish >> model and import it to ROACH2 if I need to, thanks for the info. >> >> On a sidenote: It is possible still to join the slack? I remember >> something was mentioned about sending an email earlier this year. >> >> Thanks, >> >> Franco >> >> On Mon, Dec 30, 2019 at 3:10 PM Dan Werthimer <[email protected]> >> wrote: >> >>> >>> hi franco, >>> >>> are you looking for an FFT with a real input and complex output? >>> >>> you mentioned you are connected the unused inputs of the the >>> biplex_real-4x to ground. >>> this is useful, as the compiler should remove all the unused parts of >>> the FFT, >>> although it's probably not as resource efficient as a dedicated single >>> input real to complex FFT. >>> >>> if you need further reduction in resources, >>> nitish recently developed a single stream complex to complex fft. >>> nitish's posting on casper's snap slack channel is appended below . >>> >>> you could modify nitish's design to compute two reals in one complex >>> FFT, >>> or a single real of N points in an N/2 complex FFT. >>> >>> best wishes, >>> >>> dan >>> >>> ------------------------------ >>> new messages >>> Nitish <https://app.slack.com/team/UMWDNQD7W> 10:54 PM >>> <https://casper-astro.slack.com/archives/CMNK6V19Q/p1576911266004700> >>> Hi, in reference to our previous discussion concerning the complex FFT >>> of a single stream of samples, we wanted to share the piece of the design >>> which worked, might prove useful to someone. So, we clock the SNAP at 250 >>> MHz and ADC is done at 250 MSps, thus one sample per clock cycle. We wished >>> to perform complex FFT, which would require a block taking 1 stream at 1 >>> sample per clock. The blocks available could only take powers of 2 samples >>> in parallel from a given stream, thus we had to find another way. Thanks to >>> Jack Hickish, we managed to make a small design with the FFT internal >>> blocks which performs the job. Please find attached. Channels 1 and 2 are >>> two separate streams (two distinct signals) coming from the mixer and they >>> contain 1 complex sample per clock cycle. The example shows a 2048 points >>> FFT. The unscrambler block is needed to put some order in the frequency >>> channels output. The channels from any one output have to be put in order >>> using this small code for example: >>> >>> for i in range(0, 1024): >>> spectrum1.append(channels1[i]) >>> spectrum1.append(channels1[2047 - i]) >>> >>> (edited) >>> Single_stream_complex_FFT.jpg >>> [image: Single_stream_complex_FFT.jpg] >>> >>> <https://files.slack.com/files-pri/THU1J9JDC-FRYDQAY5S/single_stream_complex_fft.jpg> >>> >>> >>> >>> >>> >>> On Mon, Dec 30, 2019 at 9:31 AM Franco <[email protected]> wrote: >>> >>>> Hello everyone, >>>> >>>> Is there an FFT block in the CASPER library (ROACH2) that can be used >>>> as 1 input -> 1 output? The closest thing I've found is the 'fft' block >>>> which has a minimum of 2 inputs. >>>> >>>> For now I'm using the fft_biplex_real-4x and zeroing 3 of the 4 inputs, >>>> but that's wasteful. I've also tried the Xilinx FFT block, but it has a >>>> strange problem where the noise floor increase considerably when injecting >>>> a tone at the middle point between two FFT bins. >>>> >>>> Thanks, >>>> >>>> Franco Curotto >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "[email protected]" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CACBfcEnPcxk-k4oFTD__%2BVYkTsGTSc%2B85uiLqejdEUthdGXwLA%40mail.gmail.com >>>> <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CACBfcEnPcxk-k4oFTD__%2BVYkTsGTSc%2B85uiLqejdEUthdGXwLA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "[email protected]" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion on the web visit >>> https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAGHS_vFeEcLgYhcYLfL8KuYM4%3DzcDkmk4yC%2BgWWqc%2BttDi40pA%40mail.gmail.com >>> <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAGHS_vFeEcLgYhcYLfL8KuYM4%3DzcDkmk4yC%2BgWWqc%2BttDi40pA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "[email protected]" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CACBfcEn1O-RhKbRhpo2XDDgWhSpshQUadpMkq3KZ%3Dnstsgzwtw%40mail.gmail.com >> <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CACBfcEn1O-RhKbRhpo2XDDgWhSpshQUadpMkq3KZ%3Dnstsgzwtw%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- > You received this message because you are subscribed to the Google Groups " > [email protected]" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CADTJ%3DnE9-ZyknDA%3DX5pOujeuTQi2O0qjfz%2BZWKdV0bSS3dE7uQ%40mail.gmail.com > <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CADTJ%3DnE9-ZyknDA%3DX5pOujeuTQi2O0qjfz%2BZWKdV0bSS3dE7uQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CACBfcE%3DT25R9NytPHT7xYG5MFdYuK1051CaGcJ6tAtMt075apQ%40mail.gmail.com.
