File size: 2,434 Bytes
75fc2d6 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 | # CISR24 generation algorithm
The MATLAB implementation in `matlab/generate_cisr24_dataset.m` is the
executable source of truth. This pseudocode documents its release contract.
```text
for split_id, split in [train, val, test]:
for class_id, waveform specification in classes.csv order:
for snr_id, snr_db in [-20, -18, ..., 20]:
for local_sample_id in [1, ..., count(split)]:
seed = 20260410
+ 30000000 * split_id
+ 1000000 * class_id
+ 10000 * snr_id
+ local_sample_id
rng(seed, "twister")
parameters = draw only from the paper's class-specific sets
burst = generate_complex_baseband_waveform(class_id, parameters)
burst = burst * exp(j * uniform(0, 2*pi))
burst = burst / sqrt(mean(abs(burst)^2))
start = uniform_integer(0, 1024 - len(burst))
record = complex_zeros(1024)
record[start : start + len(burst)] = burst
noise_power = 10^(-snr_db / 10)
noise = sqrt(noise_power / 2) * (randn(1024) + j*randn(1024))
record = record + noise
append float32 [I, Q] to /iq
append class_id, snr_db, and global sample index to HDF5
append seed, support, taxonomy, and waveform parameters to manifest
```
`split_id`, `class_id`, and `snr_id` are zero based in the formula. The local
sample ID is one based. The resulting 705,600 seeds are unique and remain below
the `uint32` limit.
## Physical conformance rules
- Linear PSK/QAM uses RRC shaping with `sps=4`, `Rs=2.5 Msps`, span 8, and
beta in `{0.25, 0.35}`.
- 4FSK/8FSK uses CPFSK `h=0.5`, `sps=8`, and `Rs=1.25 Msps`, giving actual
adjacent tone spacing `0.625 MHz`.
- GMSK and LFM-GMSK use `BT=0.3`, pulse length 4, and `sps=4`.
- OFDM-LFM chirp-enhanced carriers use a centered time coordinate and symmetric
sweep around each subcarrier. Generation aborts if instantaneous frequency
reaches Nyquist.
- Barker and Costas distribute the selected paper active length across chips by
at most one sample and record the actual minimum/maximum chip width.
## Completion semantics
Generation starts with `generation_status=in_progress`. A successful generator
sets it to `complete` and records exactly 705,600 samples. External packaging
keeps `.INCOMPLETE` until validation, full-grid SNR checks, shortcut audit,
paper alignment, loader tests, checksums, and the release gate all pass.
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