gr-apollo/tests/conftest.py
Ryan Malloy 0ee7ff0ad7 Implement full Apollo USB downlink decoder chain
Complete signal processing pipeline from complex baseband to decoded
PCM telemetry, verified against the 1965 NAA Study Guide (A-624):

Core demod (Phase 1):
  - PM demodulator with carrier PLL recovery
  - 1.024 MHz subcarrier extractor (bandpass + downconvert)
  - BPSK demodulator with Costas loop + symbol sync
  - Convenience hier_block2 combining subcarrier + BPSK

PCM frame processing (Phase 2):
  - 32-bit frame sync with Hamming distance correlator
  - SEARCH/VERIFY/LOCKED state machine, complement-on-odd handling
  - Frame demultiplexer (128-word, A/D voltage scaling)
  - AGC downlink decoder (15-bit word reassembly from DNTM1/DNTM2)

Voice and analog (Phase 3):
  - 1.25 MHz FM voice subcarrier demod to 8 kHz audio
  - SCO demodulator for 9 analog sensor channels (14.5-165 kHz)

Virtual AGC integration (Phase 4):
  - TCP bridge client with auto-reconnect and channel filtering
  - DSKY uplink encoder (VERB/NOUN/DATA command sequences)

Top-level receiver (Phase 5):
  - usb_downlink_receiver hier_block2: one block, complex in, PDUs out
  - 14 GRC block YAML definitions for GNU Radio Companion
  - Example scripts for signal analysis and full-chain demo

Infrastructure:
  - constants.py with all timing/frequency/frame parameters
  - protocol.py for sync word + AGC packet encode/decode
  - Synthetic USB signal generator for testing
  - 222 tests passing, ruff lint clean
2026-02-20 13:18:42 -07:00

78 lines
1.8 KiB
Python

"""Shared test fixtures for gr-apollo."""
import numpy as np
import pytest
from apollo.constants import (
PCM_HIGH_BIT_RATE,
PCM_HIGH_WORDS_PER_FRAME,
PCM_LOW_BIT_RATE,
PCM_LOW_WORDS_PER_FRAME,
SAMPLE_RATE_BASEBAND,
)
from apollo.usb_signal_gen import generate_pcm_frame, generate_usb_baseband
@pytest.fixture
def sample_rate():
return SAMPLE_RATE_BASEBAND
@pytest.fixture
def high_rate_params():
return {
"bit_rate": PCM_HIGH_BIT_RATE,
"words_per_frame": PCM_HIGH_WORDS_PER_FRAME,
}
@pytest.fixture
def low_rate_params():
return {
"bit_rate": PCM_LOW_BIT_RATE,
"words_per_frame": PCM_LOW_WORDS_PER_FRAME,
}
@pytest.fixture
def known_payload():
"""A known 124-byte payload (words 5-128) for frame verification."""
np.random.seed(42)
return bytes(np.random.randint(0, 256, size=124, dtype=np.uint8))
@pytest.fixture
def single_frame_bits(known_payload):
"""A single high-rate frame with known payload, as bit list."""
return generate_pcm_frame(frame_id=1, odd=True, data=known_payload)
@pytest.fixture
def clean_baseband(known_payload):
"""Clean (no noise) single-frame baseband signal with known payload."""
signal, frame_bits = generate_usb_baseband(
frames=1,
frame_data=[known_payload],
snr_db=None,
)
return signal, frame_bits[0]
@pytest.fixture
def noisy_baseband(known_payload):
"""Noisy (20 dB SNR) single-frame baseband signal."""
signal, frame_bits = generate_usb_baseband(
frames=1,
frame_data=[known_payload],
snr_db=20.0,
)
return signal, frame_bits[0]
@pytest.fixture
def multi_frame_baseband():
"""5-frame baseband signal for frame sync testing."""
np.random.seed(123)
signal, frame_bits = generate_usb_baseband(frames=5, snr_db=30.0)
return signal, frame_bits