On Thu, Mar 31, 2016 at 7:42 PM, Robert Jördens <jord...@gmail.com> wrote: > On Thu, Mar 31, 2016 at 7:25 PM, Slichter, Daniel H. (Fed) > <daniel.slich...@nist.gov> wrote: >> - For sc qubit applications, it would be necessary to update the u and a >> interpolators at the full output rate (~1.25 GSPS), since pulses are often >> only 10-20 ns long and require nontrivial shaping over those periods of time >> (sometimes 2 envelope oscillations up and down, see e.g. >> http://arxiv.org/pdf/1405.0450v2.pdf on "wah-wah" pulses, which are commonly >> used). In general, having u and a only updated at 1/8 clock rate will give >> rise to spurs at 1/4 of the Nyquist frequency and harmonics, which is >> undesirable for any application. Perhaps I am misunderstanding what you >> mean by the interpolators running at 1/8 output date. >> Will changing the update rate for the spline interpolators make things much >> larger? I assume they would have to be physically parallelized. > > It is extremely hard to play the trick that I am doing for the DUC > phase for higher order polynomials. It doesn't work mathematically. > Making the trick work would require either restricting the > interpolators to linear interpolation or a sizable number of actual > multipliers. I would have to test how bad it is. And it would also > increase the spline knot duration granularity by a factor of 8.
And a 16 ns pulse would be just about 20 samples. Why would you want to describe that using ~4 spline knots each being maybe 16 times 16 bits in data. If you need the full bandwidth, the idea of compression using splines is not very helpful. In that case you would need to design in a little "real" AWG player that plays snippets from a wide BRAM. _______________________________________________ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
