Ryan Malloy
ec0dfedc50
Implement precision timing recovery functions: - _refine_symbol_boundary(): Scans at 1/32-symbol resolution to find exact chirp boundary by maximizing dechirped SNR - _find_sfd_boundary(): FFT-based correlation with downchirp template to find exact data start position Bug fixes: - Fix _is_downchirp() false positives by comparing both correlations - Fix _estimate_cfo() to return values in [0, N) range The improved sync_from_samples() now produces bins identical to the reference lora_decode_gpu decoder.
99 lines
3.0 KiB
Python
99 lines
3.0 KiB
Python
#!/usr/bin/env python3
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"""Debug FrameSync step by step."""
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import sys
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from pathlib import Path
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import numpy as np
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sys.path.insert(0, str(Path(__file__).parent.parent / "python"))
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from rylr998 import Channelizer, FrameSync
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from rylr998.frame_sync import FrameSyncState
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# Params
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INPUT_SAMPLE_RATE = 2e6
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CENTER_FREQ = 915e6
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CHANNEL_FREQ = 915e6
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CHANNEL_BW = 125e3
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SF = 9
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# Load and channelize
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capture_path = Path(__file__).parent.parent.parent / "gnuradio" / "logs" / "capture_multi.raw"
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iq_raw = np.fromfile(capture_path, dtype=np.complex64)
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print(f"Loaded {len(iq_raw):,} samples")
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ch = Channelizer(INPUT_SAMPLE_RATE, CHANNEL_BW, CENTER_FREQ, CHANNEL_FREQ)
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iq_ch = ch.channelize(iq_raw)
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print(f"Channelized to {len(iq_ch):,} samples")
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# Extract region around frame (4.2 - 4.7 seconds)
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start_sample = int(4.2 * CHANNEL_BW)
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end_sample = int(4.7 * CHANNEL_BW)
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iq_slice = iq_ch[start_sample:end_sample]
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print(f"Extracted {len(iq_slice):,} samples ({len(iq_slice)/CHANNEL_BW:.1f}s)")
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# Create FrameSync
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sync = FrameSync(sf=SF, sample_rate=CHANNEL_BW, bw=CHANNEL_BW)
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sps = sync.sps
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N = sync.N
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print(f"\nFrameSync: SF={SF}, N={N}, sps={sps}")
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print("=" * 70)
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# Process symbol by symbol with state tracking
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n_symbols = len(iq_slice) // sps
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print(f"Processing {n_symbols} symbols...\n")
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for i in range(min(n_symbols, 80)):
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sym_samples = iq_slice[i*sps:(i+1)*sps]
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prev_state = sync._state.name
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peak_bin, peak_mag = sync._dechirp_and_peak(sym_samples)
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# Check what _is_preamble_chirp would return
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is_pre = sync._is_preamble_chirp(peak_bin, peak_mag)
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# Check downchirp
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is_dc, dc_mag = sync._is_downchirp(sym_samples)
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# Process
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result = sync.process_symbol(sym_samples)
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new_state = sync._state.name
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# Build status line
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status = f"sym {i:3d}: bin={peak_bin:3d} snr={peak_mag:5.1f}x"
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status += f" isPre={is_pre} isDC={is_dc}"
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status += f" state: {prev_state:10s} → {new_state:10s}"
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# Add extra info based on state
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if new_state == 'PREAMBLE':
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status += f" (count={sync._preamble_count}, cfo={sync._cfo_estimate:.1f})"
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elif new_state == 'SYNC_WORD':
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status += f" (sync_bins={sync._sync_bins})"
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elif new_state == 'SFD':
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status += f" (sfd_count={sync._sfd_count})"
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elif new_state == 'DATA':
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status += f" (data_len={len(sync._data_bins)})"
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print(status)
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if result is not None:
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print(f"\n*** FRAME DETECTED ***")
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print(f" networkid = {result.networkid}")
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print(f" cfo_bin = {result.cfo_bin}")
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print(f" data_symbols = {len(result.data_symbols)}")
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break
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# Try sync_from_samples directly
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print("\n" + "=" * 70)
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print("Trying sync_from_samples on the same data slice...")
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sync.reset()
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result = sync.sync_from_samples(iq_slice, max_data_symbols=50)
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print(f"Result found: {result.found}")
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print(f" networkid: {result.networkid}")
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print(f" cfo_bin: {result.cfo_bin}")
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print(f" preamble_count: {result.preamble_count}")
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print(f" data_symbols: {len(result.data_symbols)}")
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print(f" sync_word_raw: {result.sync_word_raw}")
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