See also
An IPython notebook version of this tutorial can be downloaded here:
Advanced sequencing¶
In this tutorial we will demonstrate advanced sequencer based operations, where we focus on waveform parametrization (see section Sequencer). We will demonstrate this by creating a sequence that will show various sequencer features, including complex looping constructs, dynamic gain control, hardware-based modulation and markour output control.
The sequence itself will use four waveform envelopes with a duration of 1μs each; a gaussian, a sine, a sawtooth and a block. We will have several nested loops in the sequence. The first loop will increase the wait period between the start of the iteration and playback of the waveform envelope and also increase the gain of the waveform envelope on every iteration. At the end of this loop a second loop will do the inverse operations. A third loop will loop over the first and second loops to iterate over the four waveform envelopes. And finally a fourth loop will function as an infinite loop over the third loop. At the same time, the sequence will also control marker output 1 and create a trigger point at the start of each iteration of the first and second loops as well an “enable” during playback. Finally, each waveform envelope will be modulated at 10MHz.
The result of this sequence, when observed on an oscilloscope, will be iterating waveform envelopes that will be sliding over the modulation frequency with varying gain, encapsulated by an “enable” on the marker output. We highly recommend that you take a look at it, to get an impression of what is possible with the sequencers.
This tutorial is designed with the Pulsar QCM in mind, but can easily be used with a Pulsar QRM as well. Change any Pulsar QCM reference to Pulsar QRM and only use one sequencer.
Setup¶
First, we are going to import the required packages and connect to the instrument.
[1]:
#Set up the environment.
import pprint
import os
import scipy.signal
import math
import json
import matplotlib.pyplot
import numpy
from pulsar_qcm.pulsar_qcm import pulsar_qcm
#Connect to the Pulsar QCM at default IP address.
pulsar = pulsar_qcm("qcm", "192.168.0.2")
#Reset the instrument for good measure.
pulsar.reset()
print("Status:")
print(pulsar.get_system_status())
Status:
{'status': 'OKAY', 'flags': []}
Generate waveforms¶
Next, we need to create the gaussian, sine, sawtooth and block waveform envelopes for the sequence.
[2]:
#Waveform parameters
waveform_length = 1000 #nanoseconds
#Waveform dictionary (data will hold the samples and index will be used to select the waveforms in the instrument).
waveforms = {
"gaussian": {"data": [], "index": 0},
"sine": {"data": [], "index": 1},
"sawtooth": {"data": [], "index": 2},
"block": {"data": [], "index": 3}
}
#Create gaussian waveform
if "gaussian" in waveforms:
waveforms["gaussian"]["data"] = scipy.signal.gaussian(waveform_length, std=0.12 * waveform_length)
#Create sine waveform
if "sine" in waveforms:
waveforms["sine"]["data"] = [math.sin((2 * math.pi / waveform_length) * i ) for i in range(0, waveform_length)]
#Create sawtooth waveform
if "sawtooth" in waveforms:
waveforms["sawtooth"]["data"] = [(1.0 / (waveform_length)) * i for i in range(0, waveform_length)]
#Create block waveform
if "block" in waveforms:
waveforms["block"]["data"] = [1.0 for i in range(0, waveform_length)]
Let’s plot the waveforms to see what we have created.
[3]:
time = numpy.arange(0, max(map(lambda d: len(d["data"]), waveforms.values())), 1)
fig, ax = matplotlib.pyplot.subplots(1,1, figsize=(10, 10/1.61))
ax.set_ylabel("Waveform primitive amplitude")
ax.set_xlabel("Time (ns)")
for wf, d in waveforms.items():
ax.plot(time[:len(d["data"])], d["data"], ".-", linewidth=0.5, label=wf)
ax.legend(loc=4)
ax.yaxis.grid()
ax.xaxis.grid()
matplotlib.pyplot.draw()
matplotlib.pyplot.show() # add this at EOF to prevent execution stall
Create Q1ASM program¶
Now that we have the waveforms for the sequence, we need a Q1ASM program that sequences the waveforms as previously described.
[4]:
#Sequence program.
seq_prog = """
wait_sync 4 #Wait for synchronization
start: move 4,R0 #Init number of waveforms
move 0,R1 #Init waveform index
mult_wave_loop: move 166,R2 #Init number of single wave loops (increasing wait)
move 166,R3 #Init number of single wave loops (decreasing wait)
move 24,R4 #Init number of dynamic wait time (total of 4us)
move 3976,R5 #Init number of dynamic wait time remainder
move 32768,R6 #Init gain (Maximum gain)
sngl_wave_loop_0: move 800,R7 #Init number of long wait loops (total of 40ms)
set_mrk 15 #Set marker to 0xF
upd_param 4 #Update all parameters and wait 4ns
set_mrk 0 #Set marker to 0
upd_param 96 #Update all parameters and wait 96ns
wait R4 #Dynamic wait
add R4,24,R4 #Increase wait
set_mrk 1 #Set marker to 1
play R1,R1,996 #Play waveform and wait 996ns
set_mrk 0 #Set marker to 0
upd_param 4 #Update all parameters and wait for 4ns
wait R5 #Compensate previous dynamic wait
sub R5,24,R5 #Decrease wait
sub R6,98,R6 #Decrease gain
nop
set_awg_gain R6,R6 #Set gain
long_wait_loop_0: wait 50000 #Wait 50 us
loop R7,@long_wait_loop_0 #Wait total of 40ms
loop R2,@sngl_wave_loop_0 #Repeat single wave loop
sngl_wave_loop_1: move 800,R7 #Init number of long wait loops (total of 40ms)
set_mrk 15 #Set marker to 0xF
upd_param 8 #Update all parameters and wait 8ns
set_mrk 0 #Set marker to 0
upd_param 92 #Update all parameters and wait 92ns
wait R4 #Dynamic wait
sub R4,24,R4 #Decrease wait
set_mrk 1 #Set marker to 1
play R1,R1,996 #Play waveform and wait 996ns
set_mrk 0 #Set marker to 0
upd_param 4 #Update all parameters and wait 4ns
wait R5 #Compensate previous dynamic wait
add R5,24,R5 #Increase wait
sub R6,98,R6 #Decrease gain
nop
set_awg_gain R6,R6 #Set gain
long_wait_loop_1: wait 50000 #Wait for 50 us
loop R7,@long_wait_loop_1 #Wait total of 40ms
loop R3,@sngl_wave_loop_1 #Repeat single wave loop
add R1,1,R1 #Adjust waveform index
loop R0,@mult_wave_loop #Repeat with next waveform envelope
jmp @start #Repeat entire sequence
"""
Upload sequence¶
Now that we have the waveforms and Q1ASM program, we can combine them in a sequence stored in a JSON file.
[5]:
#Reformat waveforms to lists if necessary.
for name in waveforms:
if str(type(waveforms[name]["data"]).__name__) == "ndarray":
waveforms[name]["data"] = waveforms[name]["data"].tolist() # JSON only supports lists
#Add sequence program and waveforms to single dictionary and write to JSON file.
wave_and_prog_dict = {"waveforms": {"awg": waveforms}, "program": seq_prog}
with open("sequence.json", 'w', encoding='utf-8') as file:
json.dump(wave_and_prog_dict, file, indent=4)
file.close()
Let’s write the JSON file to the instruments. We will use sequencer 0 and 1, which will drive outputs \(\text{O}^{[1-2]}\) and \(\text{O}^{[3-4]}\) respectively.
[6]:
#Upload waveforms and programs.
pulsar.sequencer0_waveforms_and_program(os.path.join(os.getcwd(), "sequence.json"))
pulsar.sequencer1_waveforms_and_program(os.path.join(os.getcwd(), "sequence.json"))
Play sequence¶
The sequence has been uploaded to the instrument. Now we need to configure the sequencers in the instrument to use the wait_sync instruction at the start of the Q1ASM program to synchronize and to enable the hardware-based modulation at 10MHz.
[7]:
#Configure the sequencers to synchronize and enable modulation at 10MHz.
pulsar.sequencer0_sync_en(True)
pulsar.sequencer0_mod_en_awg(True)
pulsar.sequencer0_nco_freq(10e6)
pulsar.sequencer1_sync_en(True)
pulsar.sequencer1_mod_en_awg(True)
pulsar.sequencer1_nco_freq(10e6)
Now let’s start the sequence. If you want to observe the sequence, this is the time to connect an oscilloscope to marker output 1 and one or more of the four outputs. Configure the oscilloscope to trigger on marker output 1.
[8]:
#Arm and start both sequencers.
pulsar.arm_sequencer()
pulsar.start_sequencer()
#Print status of both sequencers.
print("Status:")
print(pulsar.get_sequencer_state(0))
print(pulsar.get_sequencer_state(1))
Status:
{'status': 'RUNNING', 'flags': []}
{'status': 'RUNNING', 'flags': []}
Before we continue, have you looked at the oscilloscope? Pretty nifty right? This is just an example. Imaging what else you can do with the power of the sequencers to control and/or speed up your experiments.
Stop¶
Finally, let’s stop the sequencers if they haven’t already and close the instrument connection.
[9]:
#Stop both sequencers.
pulsar.stop_sequencer()
#Print status of both sequencers (should now say it is stopped).
print("Status:")
print(pulsar.get_sequencer_state(0))
print(pulsar.get_sequencer_state(1))
print()
#Print an overview of the instrument parameters.
print("Snapshot:")
pulsar.print_readable_snapshot(update=True)
#Close the instrument connection.
pulsar.close()
Status:
{'status': 'STOPPED', 'flags': ['FORCED STOP']}
{'status': 'STOPPED', 'flags': ['FORCED STOP']}
Snapshot:
qcm:
parameter value
--------------------------------------------------------------------------------
IDN : {'manufacturer': 'Qblox', 'devi...
reference_source : internal
sequencer0_cont_mode_en_awg_path0 : False
sequencer0_cont_mode_en_awg_path1 : False
sequencer0_cont_mode_waveform_idx_awg_path0 : 0
sequencer0_cont_mode_waveform_idx_awg_path1 : 0
sequencer0_gain_awg_path0 : 1
sequencer0_gain_awg_path1 : 1
sequencer0_marker_ovr_en : False
sequencer0_marker_ovr_value : 0
sequencer0_mod_en_awg : True
sequencer0_nco_freq : 1e+07 (Hz)
sequencer0_nco_phase_offs : 0 (Degrees)
sequencer0_offset_awg_path0 : 0
sequencer0_offset_awg_path1 : 0
sequencer0_sync_en : True
sequencer0_upsample_rate_awg_path0 : 0
sequencer0_upsample_rate_awg_path1 : 0
sequencer0_waveforms_and_program : C:\Users\jordy\Projects\pulsar_...
sequencer1_cont_mode_en_awg_path0 : False
sequencer1_cont_mode_en_awg_path1 : False
sequencer1_cont_mode_waveform_idx_awg_path0 : 0
sequencer1_cont_mode_waveform_idx_awg_path1 : 0
sequencer1_gain_awg_path0 : 1
sequencer1_gain_awg_path1 : 1
sequencer1_marker_ovr_en : False
sequencer1_marker_ovr_value : 0
sequencer1_mod_en_awg : True
sequencer1_nco_freq : 1e+07 (Hz)
sequencer1_nco_phase_offs : 0 (Degrees)
sequencer1_offset_awg_path0 : 0
sequencer1_offset_awg_path1 : 0
sequencer1_sync_en : True
sequencer1_upsample_rate_awg_path0 : 0
sequencer1_upsample_rate_awg_path1 : 0
sequencer1_waveforms_and_program : C:\Users\jordy\Projects\pulsar_...