It seems to be both 10.1 and 7.1. I just tested the biplex_cplx_unscrambler, comparing the pink block to the 10.1 version. I built an identical test bench for each and found no differences for size 2^4, so that doesn't seem to be the source of the problem. Glenn
On Fri, Sep 19, 2008 at 1:11 AM, Andrew Martens <[email protected]>wrote: > Hi > > Is this in the 10.1 or 7.1 library? I have made some recent changes to the > 10.1 FFT subsection and am a bit worried I broke something. It should not > have affected the data, only the of output, but the road to hell is paved > with good intentions. > > Will look into it today as well. > > Cheers > Andrew > > 2008/9/19 G Jones <[email protected]> > > Attached is a simple 7.1 model that illustrates the problem. The out0 from >> each fft is different even though the pol0 input is the same. The only >> difference is the pol1 input. >> The green block implementation is significantly different from the pink as >> far as the reordering, so this may be difficult to track down >> Glenn >> >> >> On Thu, Sep 18, 2008 at 6:14 PM, G Jones <[email protected]> wrote: >> >>> Thanks for clarifying Aaron, I will go through the block carefully >>> tonight and see if I can trace down the "cross-coupling." >>> Glenn >>> >>> >>> On Thu, Sep 18, 2008 at 6:12 PM, Aaron Parsons < >>> [email protected]> wrote: >>> >>>> Your description of what the FFT block *should* do for n_inputs = 2^0 >>>> is correct. Assuming the output has been correctly descrambled into >>>> to separate the spectra of the two inputs, one input should not >>>> influence the other's spectrum in any way. This has been tested >>>> extensively in the library as I left it last summer. If this is not >>>> the behavior that you are seeing, then I suspect an error in one of >>>> the mask scripts has been introduced during this massive code >>>> migration. >>>> >>>> As for the PFB FIR, it is correct that in "biplex mode" it simply >>>> makes two copies of the same polyphase filter. >>>> >>>> On Thu, Sep 18, 2008 at 8:19 PM, G Jones <[email protected]> >>>> wrote: >>>> > Hello, >>>> > I am trying to use the green FFT block with number of simultaneous >>>> inputs >>>> > set to 0. My understanding was that this makes a biplex fft that >>>> processes >>>> > two independant data streams in parallel, thus the pol0 input should >>>> have x0 >>>> > x1 x2... and pol1 should have y0 y1 y2 and then the pol0 output will >>>> just >>>> > have frequencies related to pol0. However, when I simulate this, I >>>> find that >>>> > the two inputs are interacting. If I set one input to a constant, the >>>> output >>>> > is significantly different than if I connect the two inputs together >>>> (in >>>> > which case I should get two identical copies at the output. >>>> > I did notice in the packetized correlator iBOB design (using pink >>>> blocks) >>>> > the pfb_fir block preceeding the fft is set to biplex mode, but I had >>>> > assumed this didn't change the functionality of the block since a >>>> biplex >>>> > pfb_fir block should be equivalent two single input pfb_fir blocks. >>>> > Can someone more clearly explain the functionality of the FFT block? >>>> > Thank you, >>>> > Glenn >>>> > >>>> >>>> >>>> >>>> -- >>>> Aaron Parsons >>>> >>>> 510-406-4322 (cell) >>>> 787-878-2612 x329 (arecibo office) >>>> 787-721-3991 (home) >>>> >>> >>> >> >
