Long pulses - #1492
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| phase_post = [Move(source=minus_phase, destination=Registers.phase_delta.value)] | ||
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| if duration_sweep: | ||
| hold: list[Instruction] = [Wait(duration=duration_sweep[ParamRole.DURATION])] |
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Substract the 4 from the register here.
| value_0=int(convert(pulse.amplitude, Parameter.amplitude)), value_1=0 | ||
| ), | ||
| Line( | ||
| instruction=UpdParam(duration=4), |
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Instead of fixing this to 4, we can pass here a register, and remove the hold (wait instruction), which will be the duration of the pulkse.
| + hold | ||
| + phase_post | ||
| + [SetAwgOffs(value_0=0, value_1=0)] | ||
| # Line(instruction=UpdParam(duration=4))] # This may be neeed if this is the last pulse in the sequence, otherwise it will never turn off the tone. |
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Btw, the Qblox documentation is a bit misleading about this point. But eventually clear.
Some classical instructions like
set_awg_offsandset_freqchange special latched registers in the FPGA. These registers hold or latch the value until a RT instruction (such asupd_paramorplay) applies them to the parts of the sequencer that deal with signals.
[...]2. The
waitRT instruction does not update latched parameters.
https://docs.qblox.com/en/v2026.04.0/products/architecture/sequencers/sequencer.html#latched-instructions
(emphasis mine)
So, if you want to make sure to end your pulse at the correct time, you need to append an upd_param instruction. Otherwise, it may happen to be the last instruction before reset, and your pulse will last for all the time of the reset itself (if done through relaxation).
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Add a Long Pulse object to qibolab. This generates rectangular pulses using the awg_offsets instead of the waveform.
Checklist: