Implements CDS to reduce noise by taking multiple measurements at
different source PLL phase offsets and combining with cosine weighting.
Firmware changes (VNA.cpp, Protocol.hpp):
- Add cdsPhases field to SweepSettings (0=disabled, 2-7=phase count)
- Configure N internal sweep points per user point with phase offsets
- Accumulate weighted samples: result = Σ(sample[k] × cos(2π×k/N))
- Per-stage accumulators for multi-stage measurements
PC application changes:
- Add "CDS" checkbox to VNA acquisition toolbar
- When enabled, sets cdsPhases=2 for 180° differential measurement
- Tooltip explains the feature
With 180° CDS (2 samples):
- Sample at 0°: weight = cos(0°) = 1
- Sample at 180°: weight = cos(180°) = -1
- Combined result = Sample₀ - Sample₁₈₀
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add Z parameters with general conversion from and to S parameters
- Implement impedance renormalization over general Z parameters
- Fix crash after taking de-embedding measurement
- Fix various small bugs with new parameter implementation
- Bugfixes:
- improve SPI timing in FPGA
- fix markers and reduce CPU load when using markers with fast traces
- New features:
- dwell time configurable in acquisition toolbar
- PLL settling delay in device configuration
- device configuration persistent across power cycles
