Windowing (pulse shaping) Phaser Output

ajras

Hi all,

I've been looking into windowed output (aka pulse shaping) from the Phaser. I see it mentioned in Norman's thesis and demonstrated in Fig. 3.16 with a Hann window on a single frequency by (I assume) outputing many frequencies. However, the documentation at the end of Norman's thesis and the latest artiq version are quite different. It has me wondering how possible it is to do windowing with the latest artiq version and phaser. Does anyone have more resources, experience, or information on windowing/pulse shaping the phaser output?

Thank you in advance,
AJ

rjo

The thesis contains all the information and pointers to the code. https://github.com/quartiq/phaser/issues/14 also has some.
So far there hasn't been any more work on it that I'm aware of nor has there been enough interest that would justify further development or maintenance.

rjo

Within the scope of one of our research projects (MIQRO) we are developing a demonstrator of a system with 16 oscillators over 200 MHz that also includes 32 dynamically programmable profiles per oscillator, a dynamically programmable windower/shaper/interpolator and flexible and efficient pulse encoding for very high pulse rates. The plan is to offer this to interested trial users at some point.

rjo

To close this up: https://github.com/m-labs/artiq/pull/1962 for the merge of the ARTIQ coredevice driver for the AWG gateware and https://twitter.com/QUARTIQGmbH/status/1572225670117457921 for a little demo.

ajras

Thanks for the update @rjo. This brings me to a more specific question. In the Github issue (and thesis), it's mention that the window/shaper is working and is "specified using another 1024 point fft." What Aritq API functions modify the 1024 point fft of the window path? Is this currently part of the Phaser class?

rjo

In the stft artiq branch. Yes.
https://github.com/quartiq/artiq/tree/stft_pulsegen

ajras

Thank you! Currently, we're using the main branch of Artiq 6 from m-labs which doesn't have stft_pulsegen. We would have to switch to quartiq's artiq 6 (stft_pulsegen branch)? I'm not familiar with the differences with m-lab's artiq repo and quartiq's artiq repo nor what complications that might entail.

rjo

Yes. As explained previously, it hasn't been developed further or maintained or merged.

ajras

Ok, thank you for your patience. I'm not familiar with the history behind Artiq develop and how it's tied between various groups such as m-labs, quartiq, etc.
I'm surprised there is little interested in using windowing as it's been demonstrated as a technique for robust MS gates. What's the typical process for suggesting it as a feature? M-lab's artiq contribution guidelines don't mention a process for suggesting features. Should I make an issue on github?

rjo

Among other things there needs to be a business case for it. I.e. money and consensus that the solution is viable and strong.

ajras

Just to clarify, the Phaser MIQRO mode doesn't require new phaser hardware? It can be used with the existing phaser?

rjo

correct