Presentations
SMuRF Resonator Frequency Measurement
Zoom discussions
| date | topic | link |
|---|---|---|
| 4/26/21 | eta scans, firmware | |
| 4/27/21 | eta scans, firmware | |
| 4/28/21 | eta scans, tracking/flux ramp demodulation | |
| 4/29/21 | pilot tones | |
| 5/3/21 | polyphase filters, filter bank | |
| 5/5/21 | uMUX tracking, demodulation | |
| 5/6/21 | SMuRF tutorial | |
| 5/10/21 | Closed Loop Tracking Transfer Function uMUX simulator | |
| 5/12/21 | ||
| 5/13/21 | SMuRF Application Differences | |
| 5/13/21 | Pilot tones meeting discussion about ADC/DAC data valid flags in the SMuRF headers | |
| 5/18/21 | IQ calibration, simulator |
General background
S21 for a resonator
S21 for time delay
SMuRF Practice
Here I'll generate an S21 curve. What eta params should we use?
close all
clear
Fdsp = 2.4e6;
% can place resonator +/- Fdsp/2
fres = 300e3;
fnorm = fres/Fdsp;
z0 = 0.98*exp(1j*2*pi*fnorm);
p0 = 0.95*exp(1j*2*pi*(fnorm+0.002));
b = [1, -z0];
a = [1, -p0];
fvtool([1, -z0], [1, -p0], 'Fs', Fdsp)
theta = 0.5; % arbitrary phase offset, rad
tau = 1e-9; % 1 ns delay
% digital frequency -- -pi to pi maps to -Fs/2 to Fs/2
w = linspace(-pi, pi, 2^13);
f = w*Fdsp/2/pi; % frequencies in Hz
[s21, w] = freqz(b, a, w); % resonator S21
s21 = s21.*exp(-1j*theta); % apply arb phase offset
s21 = s21.*exp(-1j*2*pi*f*tau); % apply time delay
figure
subplot(2,1,1)
plot(f, 20*log10(abs(s21)), 'LineWidth', 2)
title('Resonator Transfer Function', 'FontSize', 12)
grid minor
xlabel('Frequency', 'FontSize', 12)
ylabel('Magnitude (dB)', 'FontSize', 12)
subplot(2,1,2)
plot(f, unwrap(angle(s21)), 'LineWidth', 2)
grid minor
xlabel('Frequency', 'FontSize', 12)
ylabel('Phase (rad)', 'FontSize', 12)
figure
plot(real(s21(1:10:end)), imag(s21(1:10:end)), '.', 'LineWidth', 2)
grid minor
title('S_{21}', 'FontSize', 12)
xlabel('Real S_{21}', 'FontSize', 12)
ylabel('Imag S_{21}', 'FontSize', 12)
Here's my result
%% Here's the real test -- move the resonator and see how it responds apply_eta = @(x, eta_offset, eta) (x + eta_offset)*eta; % can place resonator +/- Fdsp/2 dfres = 1e3; % move the resonator from it's original frequency fres = 300e3 + dfres; fnorm = fres/Fdsp; z0 = 0.98*exp(1j*2*pi*fnorm); p0 = 0.95*exp(1j*2*pi*(fnorm+0.002)); b = [1, -z0]; a = [1, -p0]; [s21, w] = freqz(b, a, w); % resonator S21 s21 = s21.*exp(-1j*theta); % apply arb phase offset s21 = s21.*exp(-1j*2*pi*tau*f); % apply time delay s21_eta = apply_eta(s21, eta_offset, eta); % apply eta disp(['We moved the resonator ', num2str(dfres), 'Hz and measured ', num2str(round(imag(s21_eta(ftone)))), ' Hz error']) >> We moved the resonator 1000Hz and measured -984 Hz error
Using Pickles cryostat at SLAC
You may need to install vncviewer, or for windows use RealVNC
sudo apt-get install tigervnc-viewer
SSH to smurf-srv24
ssh -L 5902:localhost:5902 cryo@smurf-srv24.slac.stanford.edu
Launch VNC viewer
vncviewer localhost:5902
Starting the Rogue server
cryo@smurf-srv24:~$ cd /home/cryo/docker/smurf/dev_sw/slotN/v5.0.1 cryo@smurf-srv24:~/docker/smurf/dev_sw/slotN/v5.0.1$ ./run.sh -N 3; sleep 5; docker logs smurf_server_s3 -f
Starting the PySMuRF client (jupyter-notebook)
cryo@smurf-srv24:~$ cd docker/pysmurf/dev/v4.1.0/ cryo@smurf-srv24:~/docker/pysmurf/dev/v4.1.0$ ./run.sh cryo@smurf-srv24:/usr/local/src/pysmurf$ jupyter-notebook
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