Ryan Malloy
493c21c511
Implement the transmit/generate side as streaming GNU Radio blocks, complementing the existing receive chain. Each block maps to a physical instrument on CuriousMarc's Keysight bench: pcm_frame_source - PCM bit stream generator (sync_block + FrameSourceEngine) nrz_encoder - bits to NRZ waveform (+1/-1) with upsampling bpsk_subcarrier_mod - NRZ x cos(1.024 MHz) BPSK modulator fm_voice_subcarrier_mod - 1.25 MHz FM test tone source pm_mod - phase modulator: exp(j * deviation * input) usb_signal_source - convenience wrapper wiring all blocks together Includes GRC YAML definitions for all blocks under [Apollo USB] category, 49 new tests (271 total, all passing), and a loopback test that validates the full TX->RX round trip including frame recovery with 30 dB AWGN.
48 lines
1.3 KiB
YAML
48 lines
1.3 KiB
YAML
id: apollo_bpsk_subcarrier_mod
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label: Apollo BPSK Subcarrier Mod
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category: '[Apollo USB]'
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flags: [python]
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parameters:
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- id: subcarrier_freq
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label: Subcarrier Frequency (Hz)
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dtype: real
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default: '1024000'
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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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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.bpsk_subcarrier_mod import bpsk_subcarrier_mod
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make: apollo.bpsk_subcarrier_mod.bpsk_subcarrier_mod(subcarrier_freq=${subcarrier_freq}, sample_rate=${sample_rate})
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documentation: |-
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Apollo BPSK Subcarrier Modulator
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Multiplies an NRZ baseband waveform (+1/-1) by a 1.024 MHz cosine to produce
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a BPSK-modulated subcarrier: output(t) = nrz(t) * cos(2*pi*f_sc*t).
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The cosine phase flips 180 degrees at each NRZ sign change, implementing
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bi-phase shift keying. This is the transmit-side counterpart to the
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Apollo BPSK Subcarrier Demod block.
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On the real spacecraft, the PCM encoder drives the BPSK subcarrier modulator
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before summing with the voice subcarrier for PM transmission.
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Parameters:
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subcarrier_freq: BPSK subcarrier frequency in Hz (default 1.024 MHz)
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sample_rate: Sample rate in Hz (default 5.12 MHz)
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file_format: 1
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