Matlab Analyze Ams Waveform Skill for Claude

% From workspace variables
x = t;  y = v;

% From .mat file
data = load('waveform.mat');
x = data.time;  y = data.voltage;

% From .csv
data = readmatrix('waveform.csv');
x = data(:,1);  y = data(:,2);

% From HSpice transient (.tr0)
tr0Reader('sim.tr0', 'output.mat');
data = load('output.mat');

% From HSpice AC (.ac0)
ac0Reader('sim.ac0', 'output.mat');

% From HSpice DC sweep (.sw0)
sw0Reader('sim.sw0', 'output.mat');

% From Simulink simulation output (timeseries in logsout)
sig = simOut.logsout.get('signalName').Values;
x = sig.Time(:);          % column vector
y = squeeze(sig.Data(:)); % column vector — squeeze removes trailing dims

fprintf('=== Waveform Summary ===\n');
fprintf('Points     : %d\n', numel(x));
fprintf('X range    : [%.6g, %.6g]\n', min(x), max(x));
fprintf('Y range    : [%.6g, %.6g]\n', min(y), max(y));
fprintf('Y mean     : %.6g\n', mean(y));
fprintf('Y RMS      : %.6g\n', rms(y));
if all(diff(x) > 0)
    dx = diff(x);
    if max(dx)/min(dx) < 1.01, uStr = 'yes'; else, uStr = 'no'; end
    fprintf('X step     : %.6g (uniform: %s)\n', median(dx), uStr);
    if median(dx) > 0
        fprintf('Sample rate: %.6g Hz\n', 1/median(dx));
    end
end

Available MSB analyses for time-domain waveform:

  --- Timing Measurements ---
  [1]  Rise time — timeDomainSignal2RiseTime
  [2]  Fall time — timeDomainSignal2FallTime
  [3]  Duty cycle — timeDomainSignal2DutyCycle

  --- Clock / PLL Measurements ---
  [4]  Phase noise from frequency-domain data — phaseNoiseMeasure (default Type='Frequency')
  [5]  Phase noise from time-domain voltage — phaseNoiseMeasure (Type='Time')
  [6]  Period jitter & cycle-to-cycle jitter — clockJitterMeasure
  [7]  Phase noise to jitter conversion — phaseNoiseToJitter
  [8]  Lock time from control voltage — lockTimeMeasure

  --- Resampling ---
  [9]  Anti-aliased resampling — lowpassResample

  --- ADC/DAC Characterization ---
  [10] INL / DNL measurement — inldnl
  [11] ADC calibration — calibrateADC
  [12] DAC calibration — calibrateDAC

  --- Data Import ---
  [13] HSpice transient (.tr0) — tr0Reader
  [14] HSpice AC (.ac0) — ac0Reader
  [15] HSpice DC sweep (.sw0) — sw0Reader

  --- Frequency-Domain Utilities ---
  [16] Interpolate/extrapolate to new grid — interpExtrap
  [17] Laplace to biquad SOS — laplace2sos

% Rise time — 3rd arg is [low high] percent reference levels (required)
rt = timeDomainSignal2RiseTime(x, y, [10 90]);
fprintf('Rise time (10%%-90%%): mean = %.4g s (std = %.4g s, N=%d)\n', ...
    mean(rt), std(rt), numel(rt));

% Fall time — same 3-arg signature
ft = timeDomainSignal2FallTime(x, y, [10 90]);
fprintf('Fall time (90%%-10%%): mean = %.4g s (std = %.4g s, N=%d)\n', ...
    mean(ft), std(ft), numel(ft));

% Duty cycle — returns per-cycle values for multi-cycle waveforms
dc = timeDomainSignal2DutyCycle(x, y);
fprintf('Duty cycle: mean = %.4f%%, std = %.4f%%\n', mean(dc)*100, std(dc)*100);

% Sim duration pre-check — STOP if insufficient
minDuration = 10 / min(FrOffset);   % need >= 10 cycles of lowest offset
simDuration = x(end) - x(1);
if simDuration < minDuration
    error('Simulation too short: %.4g s < %.4g s needed for %.0f Hz offset.\nIncrease sim stop time to >= %.4g s.', ...
        simDuration, minDuration, min(FrOffset), minDuration);
end

% From time-domain voltage waveform (MSB variable-step simulation output)
% Type='Time' is REQUIRED — extracts phase via zero-crossings internally
Rbw = 1e3;                          % resolution bandwidth (Hz)
FrOffset = [10e3 100e3 1e6 10e6];   % offsets to measure
[PnAtOffsets, freqAxis, pnProfile] = phaseNoiseMeasure( ...
    x(:), y(:), Rbw, FrOffset, 'on', 'PN Measurement', ...
    -inf, ...                       % 7th arg: target PN level for plot overlay (-inf = no target line)
    Type='Time');
% Note: To reduce ripple in pnProfile, use smaller RBW (increases freq resolution)
% or increase simulation duration. SpectralAverages is a PLL Testbench block
% parameter, NOT a phaseNoiseMeasure argument.

% From frequency-domain data (e.g., imported spectrum analyzer measurement)
% Default Type='Frequency': Xin=freq offset vector, Yin=power in dBc/Hz
[PnAtOffsets, freqAxis, pnProfile] = phaseNoiseMeasure( ...
    freqOffsets, pnPower_dBcHz, Rbw, FrOffset, 'on', 'PN from Spectrum');

fprintf('Phase Noise Results:\n');
for k = 1:numel(FrOffset)
    fprintf('  @ %.0f kHz : %.1f dBc/Hz\n', FrOffset(k)/1e3, PnAtOffsets(k));
end

% Save figure for Claude to read
figPath = fullfile(tempdir, 'phase_noise_plot.png');
saveas(gcf, figPath);
fprintf('Phase noise figure saved to: %s\n', figPath);

% Clock jitter from time-domain waveform
% Returns 2 outputs: [periodJitter, c2cJitter] (RMS values)
% threshold MUST cross the signal — use midpoint or known logic level
% Inputs must be column vectors
threshold = (max(y) + min(y)) / 2;
clockFreq = 1e9;     % expected clock frequency (Hz)
[periodJitter, c2cJitter] = clockJitterMeasure(x(:), y(:), threshold, clockFreq);
fprintf('Period jitter (RMS): %.4f ps\n', periodJitter * 1e12);
fprintf('C2C jitter (RMS)   : %.4f ps\n', c2cJitter * 1e12);

% Convert phase noise profile to jitter
% Exclude DC bin (freqAxis==0) — integration from 0 Hz returns Inf
validIdx = freqAxis > 0;
[jitterRad, jitterDeg, jitterSec] = phaseNoiseToJitter( ...
    freqAxis(validIdx), pnProfile(validIdx), Frequency=carrierFreq);
fprintf('RMS jitter from PN : %.4f ps\n', jitterSec * 1e12);

% x = time, y = control voltage (loop filter output)
% lockTimeMeasure takes (voltage, time, tolerance) — note: voltage FIRST
% Both must be column vectors
x_col = x(:);  y_col = y(:);
targetVoltage = y_col(end);   % assume final value is lock voltage
errorTol = 0.01;              % 1% tolerance
lockTime = lockTimeMeasure(y_col, x_col, errorTol);
fprintf('Lock time (%.0f%% tolerance): %.4g s\n', errorTol*100, lockTime);

% Anti-aliased resampling to new sample time
Ts_new = 1e-9;
tq = (x(1) : Ts_new : x(end))';
cfg.OutputRiseFall = Ts_new;
cfg.NDelay = 1;
cfg.SampleMode = 'variable';
cfg.CausalMode = 'off';
y_resampled = lowpassResample(x, y, tq, cfg);
x_resampled = tq;

% ADC: uses transition-based fit (works on ANY input stimulus, not just ramps)
result = inldnl(Analog, Digital, Range, 'ADC', ...
    'INLMethod', 'All', 'DNLMethod', 'All', ...
    'OffsetErrorUnit', 'All', 'GainErrorUnit', 'All');

fprintf('Max |Endpoint INL|: %.4f LSB\n', max(abs(result.EndpointINL)));
fprintf('Max |Endpoint DNL|: %.4f LSB\n', max(abs(result.EndpointDNL)));
fprintf('Offset Error: %.4f LSB\n', result.OffsetErrorLSB);
fprintf('Gain Error: %.4f LSB\n', result.GainErrorLSB);

% DAC: uses center-based fit (FitMode='centers' is default for DAC)
result_dac = inldnl(Analog, Digital, Range, 'DAC', ...
    'INLMethod', 'All', 'DNLMethod', 'All');

% Calibrate ADC: correct offset and gain errors
y_cal = calibrateADC(Digital, NBits, Polarity);
% Or infer errors from measured data:
y_cal = calibrateADC(Analog, Digital, Range, 'OffsetError', oe, 'GainError', ge);

% Calibrate DAC:
y_cal = calibrateDAC(Digital, NBits, Polarity);
% Or with reference/bias:
y_cal = calibrateDAC(Digital, Analog, Ref, Bias);

Phase noise from a 1 GHz VCO (MSB sim, 100 us, zero-crossing):
  @ 10 kHz  : -51.8 dBc/Hz  <- marginal (sim too short)
  @ 100 kHz : -82.4 dBc/Hz  <- in 1/f^2 region, reasonable
  @ 1 MHz   : -98.4 dBc/Hz  <- approaching noise floor
  @ 10 MHz  : -127.6 dBc/Hz <- VCO open-loop thermal floor

Observations:
- -20 dB/dec slope from 10-80 kHz confirms white FM noise
- Hump at 100-300 kHz suggests loop BW artifact
- Floor at -128 dBc/Hz consistent with VCO open-loop spec
- 10 kHz result unreliable -- need >= 1 ms sim for clean data

figPath = fullfile(tempdir, 'analysis_plot.png');
saveas(gcf, figPath);
fprintf('Figure saved to: %s\n', figPath);