options:
  parameters:
    author: N1AI
    catch_exceptions: 'True'
    category: '[GRC Hier Blocks]'
    cmake_opt: ''
    comment: ''
    copyright: ''
    description: ''
    gen_cmake: 'On'
    gen_linking: dynamic
    generate_options: qt_gui
    hier_block_src_path: '.:'
    id: sbitx_lowpass
    max_nouts: '0'
    output_language: python
    placement: (0,0)
    qt_qss_theme: ''
    realtime_scheduling: ''
    run: 'True'
    run_command: '{python} -u {filename}'
    run_options: prompt
    sizing_mode: fixed
    thread_safe_setters: ''
    title: sBitx Lowpass
    window_size: (1000,1000)
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [8, 8]
    rotation: 0
    state: enabled

blocks:
- name: B
  id: variable
  parameters:
    comment: ''
    value: Fs/2
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [352, 8.0]
    rotation: 0
    state: enabled
- name: Fc
  id: variable
  parameters:
    comment: ''
    value: 24*1000
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [512, 8.0]
    rotation: 0
    state: enabled
- name: Fs
  id: variable
  parameters:
    comment: ''
    value: 96*1000
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [264, 8.0]
    rotation: 0
    state: enabled
- name: LO
  id: variable
  parameters:
    comment: ''
    value: -B / 2
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [432, 8.0]
    rotation: 0
    state: enabled
- name: dF
  id: variable_qtgui_range
  parameters:
    comment: ''
    gui_hint: ''
    label: ''
    min_len: '200'
    orient: QtCore.Qt.Horizontal
    rangeType: int
    start: '500'
    step: '500'
    stop: '8000'
    value: '1000'
    widget: counter_slider
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [592, 8.0]
    rotation: 0
    state: true
- name: samp_rate
  id: variable
  parameters:
    comment: ''
    value: 96*1000
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [168, 8.0]
    rotation: 0
    state: enabled
- name: analog_const_source_x_0
  id: analog_const_source_x
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    const: '0'
    maxoutbuf: '0'
    minoutbuf: '0'
    type: float
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [32, 376.0]
    rotation: 0
    state: true
- name: analog_sig_source_x_0_1_2
  id: analog_sig_source_x
  parameters:
    affinity: ''
    alias: ''
    amp: '1'
    comment: LO = -B / 2
    freq: LO
    maxoutbuf: '0'
    minoutbuf: '0'
    offset: '0'
    phase: '0'
    samp_rate: samp_rate
    showports: 'False'
    type: complex
    waveform: analog.GR_COS_WAVE
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [232, 408.0]
    rotation: 0
    state: enabled
- name: audio_source_0
  id: audio_source
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    device_name: hw:0,0
    maxoutbuf: '0'
    minoutbuf: '0'
    num_outputs: '1'
    ok_to_block: 'True'
    samp_rate: samp_rate
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [32, 260.0]
    rotation: 0
    state: true
- name: blocks_float_to_complex_0
  id: blocks_float_to_complex
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [264, 320.0]
    rotation: 0
    state: true
- name: blocks_multiply_xx_0_0_0
  id: blocks_multiply_xx
  parameters:
    affinity: ''
    alias: ''
    comment: Mixer
    maxoutbuf: '0'
    minoutbuf: '0'
    num_inputs: '2'
    type: complex
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [480, 336.0]
    rotation: 0
    state: enabled
- name: low_pass_filter_0_0
  id: low_pass_filter
  parameters:
    affinity: ''
    alias: ''
    beta: '6.76'
    comment: 'Cutoff is B / 2

      Decimation is 2'
    cutoff_freq: B / 2
    decim: '2'
    gain: '1'
    interp: '1'
    maxoutbuf: '0'
    minoutbuf: '0'
    samp_rate: samp_rate
    type: fir_filter_ccf
    width: B / 8
    win: window.WIN_HAMMING
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [624, 292.0]
    rotation: 0
    state: enabled
- name: note_0
  id: note
  parameters:
    alias: ''
    comment: "- Ref: https://dsp.stackexchange.com/questions/43278/how-do-i-convert-a-real-baseband-signal-to-a-complex-baseband-signal\n\
      - Second Approach: Uses a lowpass filter\n- To convert a real signal r[n] sampled\
      \ at rate 2B to its complex \n   baseband representation (sampled at rate B),\
      \ you want to map the\n   frequency content in the range [0,B) in the real signal\
      \ to the range\n   [\u2212B/2,B/2) in the resulting complex signal.\n - Multiply\
      \ r[n] by e**\u2212j(\u03C0/2)n to effect a frequency shift of \u2212B/2,\n\
      \   shifting the desired frequency content to the range [\u2212B2,B2). The\n\
      \   result is a complex signal that is centered in the appropriate place\n \
      \  (the center of the band is at zero frequency).\n - Apply a lowpass filter\
      \ to pass only the content in the range \n   [\u2212B2,B2) (to the extent required\
      \ while meeting your application's \n   antialiasing requirements).\n - Decimate\
      \ the signal by 2 by discarding every other sample. The \n   result is a complex\
      \ signal sampled at rate B."
    note: Convert real to complex
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [840, 16.0]
    rotation: 0
    state: true
- name: qtgui_sink_x_0
  id: qtgui_sink_x
  parameters:
    affinity: ''
    alias: ''
    bw: B
    comment: ''
    fc: '0'
    fftsize: '8192'
    gui_hint: (0,1,1,1)
    maxoutbuf: '0'
    minoutbuf: '0'
    name: '"Output (Complex)"'
    plotconst: 'False'
    plotfreq: 'False'
    plottime: 'False'
    plotwaterfall: 'True'
    rate: '10'
    showports: 'False'
    showrf: 'True'
    type: complex
    wintype: window.WIN_BLACKMAN_hARRIS
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [824, 308.0]
    rotation: 0
    state: enabled
- name: qtgui_sink_x_0_0
  id: qtgui_sink_x
  parameters:
    affinity: ''
    alias: ''
    bw: samp_rate
    comment: ''
    fc: '0'
    fftsize: '8192'
    gui_hint: (0,0,1,1)
    maxoutbuf: '0'
    minoutbuf: '0'
    name: '"Input (Real)"'
    plotconst: 'False'
    plotfreq: 'False'
    plottime: 'False'
    plotwaterfall: 'True'
    rate: '10'
    showports: 'False'
    showrf: 'True'
    type: float
    wintype: window.WIN_BLACKMAN_hARRIS
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [264, 196.0]
    rotation: 0
    state: enabled

connections:
- [analog_const_source_x_0, '0', blocks_float_to_complex_0, '1']
- [analog_sig_source_x_0_1_2, '0', blocks_multiply_xx_0_0_0, '1']
- [audio_source_0, '0', blocks_float_to_complex_0, '0']
- [audio_source_0, '0', qtgui_sink_x_0_0, '0']
- [blocks_float_to_complex_0, '0', blocks_multiply_xx_0_0_0, '0']
- [blocks_multiply_xx_0_0_0, '0', low_pass_filter_0_0, '0']
- [low_pass_filter_0_0, '0', qtgui_sink_x_0, '0']

metadata:
  file_format: 1
  grc_version: 3.10.8.0