id: apollo_voice_demod
label: Apollo Voice Subcarrier Demod
category: '[Apollo USB]'
flags: [python]

parameters:
- id: sample_rate
  label: Sample Rate (Hz)
  dtype: real
  default: '5120000'
- id: audio_rate
  label: Audio Output Rate (Hz)
  dtype: int
  default: '8000'

inputs:
- label: in
  domain: stream
  dtype: float

outputs:
- label: out
  domain: stream
  dtype: float

templates:
  imports: from apollo import voice_subcarrier_demod
  make: >-
    apollo.voice_subcarrier_demod.voice_subcarrier_demod(
      sample_rate=${sample_rate},
      audio_rate=${audio_rate})

documentation: |-
  Apollo Voice Subcarrier Demodulator

  Extracts the 1.25 MHz FM voice subcarrier from the PM demodulator output
  and recovers 300-3000 Hz audio. The spacecraft voice channel uses FM with
  +/-29 kHz deviation on a 1.25 MHz subcarrier.

  Output is bandpass filtered to 300-3000 Hz and resampled to the specified
  audio rate (default 8000 Hz, suitable for narrowband voice).

  Parameters:
    sample_rate: Input sample rate in Hz (default 5.12 MHz)
    audio_rate: Output audio sample rate in Hz (default 8000)

file_format: 1