Tune a transistor sweep with a UHFLI

This example sweeps a transistor gate with the Basel DAC and acquires amplitude and phase from two UHFLI demodulators. It implements the same measurement in stepped and buffered forms, making the stepped result a useful reference while the hardware timing is tuned.

Configure every demodulator

Each selected demodulator must sample fast enough for the shortest DAC point delay. The example initializes both rates and the excitation frequency from that delay:

min_delay = 0.03e-3

for demod in [0, 1]:
    sample_rate(2 / min_delay, demod_number=demod)

lockin.frequency1(2 / min_delay)

These are initial values. Verify the acquired point count and compare the curve with a stepped run before increasing the sweep speed.

Tune the buffered run

The buffered function makes three timing controls explicit:

  • trigger_delay shifts acquisition relative to the DAC update.

  • tc_factor allows for demodulator settling.

  • grid_mode="linear" resamples the acquired values onto the sweep grid.

The example scans several trigger delays and time-constant factors. Use a small, safe gate range for that calibration, then retain the settings that reproduce the stepped reference without missing samples.

Full example: buffered_basel_transistor_test_uhfli.py