Ryan Malloy
0ee7ff0ad7
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
48 lines
1.1 KiB
YAML
48 lines
1.1 KiB
YAML
id: apollo_voice_demod
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label: Apollo Voice Subcarrier Demod
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category: '[Apollo USB]'
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flags: [python]
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parameters:
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- id: sample_rate
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label: Sample Rate (Hz)
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dtype: real
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default: '5120000'
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- id: audio_rate
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label: Audio Output Rate (Hz)
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dtype: int
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default: '8000'
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inputs:
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- label: in
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domain: stream
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dtype: float
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outputs:
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- label: out
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domain: stream
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dtype: float
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templates:
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imports: from apollo import voice_subcarrier_demod
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make: >-
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apollo.voice_subcarrier_demod.voice_subcarrier_demod(
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sample_rate=${sample_rate},
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audio_rate=${audio_rate})
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documentation: |-
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Apollo Voice Subcarrier Demodulator
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Extracts the 1.25 MHz FM voice subcarrier from the PM demodulator output
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and recovers 300-3000 Hz audio. The spacecraft voice channel uses FM with
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+/-29 kHz deviation on a 1.25 MHz subcarrier.
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Output is bandpass filtered to 300-3000 Hz and resampled to the specified
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audio rate (default 8000 Hz, suitable for narrowband voice).
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Parameters:
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sample_rate: Input sample rate in Hz (default 5.12 MHz)
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audio_rate: Output audio sample rate in Hz (default 8000)
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file_format: 1
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