Pluto `Frequency Sweep Example gnu radio

To change the LO frequency in GR programmatically, there are two ways that come to mind. You could restart the flowgraph each time with a new LO setting for pluto. This is just a small change to the generated flowgraph in Python and introduce a loop. Or you could use the Attribute Sink block to do an attribute update for the LO frequency property of the device: https://wiki.analog.com/resources/tools-software/linux-drivers/iio-transceiver/ad9361#local_oscillator_control_lo 

-Travis

hi i have tried but failed, see attached flowgraph drive.google.com/.../1EV5vlCO6T93sB7cd1FBxEsR5SQJ05sOP, can you help to correct what am i missing to show the full spectrum instead of the moving spectrum.

also how to connect it as input to the detector in the bandlimited threshold detector example

i tried in python too but something is wrong there also. i cant get the whole spectrum to be displayed at one go  - python code also in the same folder shared above myscanner.py

thanks travis - please find files at https://file.io/gWWwOSUBR7WL

What is the problem you are observing?

-Travis

i am only able to get a portion of the spectrum value charted whereas i want to show the full spectrum range that the sdr has. Also i could not figure out how to merge the bandwidth threshold logger flowgrah to be adapted to a realword sdr

navka said:

i am only able to get a portion of the spectrum value charted whereas i want to show the full spectrum range that the sdr has.

What is limiting this?

-Travis

Dear Travis,

my knownledge is limiting me create a flowgraph suitable for the purpose

please have a look at the flowgraph and advise what needs to be corrected, currently the fft is on autoscroll for the current bandwidth in centre.

Appreciate your support

code as below for grc

options:
  parameters:
    author: navneet
    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: sweeperbyalienai23
    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: Frequency Sweeper
    window_size: (1000,1000)
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [8, 8]
    rotation: 0
    state: enabled

blocks:
- name: bandwidthrx
  id: variable
  parameters:
    comment: ''
    value: '5200000'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1168, 8.0]
    rotation: 0
    state: true
- name: freq
  id: variable
  parameters:
    comment: ''
    value: python_mod.sweeper(fun_prob)
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [552, 16.0]
    rotation: 0
    state: enabled
- name: freqmim
  id: variable_qtgui_range
  parameters:
    comment: ''
    gui_hint: ''
    label: 'Frequency Min '
    min_len: '200'
    orient: QtCore.Qt.Horizontal
    rangeType: float
    start: '0'
    step: '1000000'
    stop: '6000000000'
    value: '70000000'
    widget: counter_slider
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1336, 4.0]
    rotation: 0
    state: true
- name: frequency
  id: variable_qtgui_label
  parameters:
    comment: ''
    formatter: None
    gui_hint: ''
    label: 'Frequency '
    type: real
    value: freq
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [680, 4.0]
    rotation: 0
    state: true
- name: fun_prob
  id: variable_function_probe
  parameters:
    block_id: probSign
    comment: ''
    function_args: ''
    function_name: level
    poll_rate: '10'
    value: '0'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [8, 428.0]
    rotation: 0
    state: true
- name: samp_rate
  id: variable
  parameters:
    comment: ''
    value: '56000000'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [8, 120.0]
    rotation: 0
    state: enabled
- name: variable_qtgui_label_0
  id: variable_qtgui_label
  parameters:
    comment: ''
    formatter: None
    gui_hint: ''
    label: amp
    type: real
    value: '0'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [8, 188.0]
    rotation: 0
    state: true
- name: analog_noise_source_x_0
  id: analog_noise_source_x
  parameters:
    affinity: ''
    alias: ''
    amp: '1'
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    noise_type: analog.GR_GAUSSIAN
    seed: '0'
    type: float
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [280, 164.0]
    rotation: 0
    state: disabled
- name: analog_sig_source_x_0
  id: analog_sig_source_x
  parameters:
    affinity: ''
    alias: ''
    amp: '1'
    comment: ''
    freq: '0'
    maxoutbuf: '0'
    minoutbuf: '0'
    offset: '0'
    phase: '0'
    samp_rate: samp_rate
    type: complex
    waveform: analog.GR_CONST_WAVE
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [8, 284.0]
    rotation: 0
    state: disabled
- name: analog_sig_source_x_1
  id: analog_sig_source_x
  parameters:
    affinity: ''
    alias: ''
    amp: '1'
    comment: ''
    freq: freq
    maxoutbuf: '0'
    minoutbuf: '0'
    offset: '0'
    phase: '0'
    samp_rate: samp_rate
    type: float
    waveform: analog.GR_COS_WAVE
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [280, 4.0]
    rotation: 0
    state: disabled
- name: blocks_add_xx_0
  id: blocks_add_xx
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    num_inputs: '2'
    type: float
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [600, 136.0]
    rotation: 0
    state: disabled
- name: blocks_throttle_0
  id: blocks_throttle
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    ignoretag: 'True'
    maxoutbuf: '0'
    minoutbuf: '0'
    samples_per_second: samp_rate
    type: complex
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [280, 328.0]
    rotation: 0
    state: disabled
- name: blocks_throttle_0_0
  id: blocks_throttle
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    ignoretag: 'True'
    maxoutbuf: '0'
    minoutbuf: '0'
    samples_per_second: samp_rate*4
    type: complex
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1008, 512.0]
    rotation: 0
    state: disabled
- name: fft_vxx_0
  id: fft_vxx
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    fft_size: '1024'
    forward: 'True'
    maxoutbuf: '0'
    minoutbuf: '0'
    nthreads: '1'
    shift: 'True'
    type: float
    window: window.blackmanharris(1024)
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1256, 420.0]
    rotation: 0
    state: disabled
- name: iio_pluto_source_0
  id: iio_pluto_source
  parameters:
    affinity: ''
    alias: ''
    bandwidth: bandwidthrx
    bbdc: 'True'
    buffer_size: '32768'
    comment: ''
    filter: ''
    filter_source: '''Auto'''
    fpass: '0'
    frequency: freq
    fstop: '0'
    gain1: '''manual'''
    len_tag_key: packet_len
    manual_gain1: '64'
    maxoutbuf: '0'
    minoutbuf: '0'
    quadrature: 'True'
    rfdc: 'True'
    samplerate: ' 1920000'
    type: fc32
    uri: uri
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [760, 236.0]
    rotation: 0
    state: true
- name: logpwrfft_x_0
  id: logpwrfft_x
  parameters:
    affinity: ''
    alias: ''
    average: 'False'
    avg_alpha: '1.0'
    comment: ''
    fft_size: '1024'
    frame_rate: '30'
    maxoutbuf: '0'
    minoutbuf: '0'
    ref_scale: '2'
    sample_rate: samp_rate
    shift: 'False'
    type: complex
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1104, 224.0]
    rotation: 0
    state: disabled
- name: probSign
  id: blocks_probe_signal_x
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    type: complex
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1080, 416.0]
    rotation: 0
    state: enabled
- name: probSign1
  id: blocks_probe_signal_x
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    type: complex
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [520, 408.0]
    rotation: 0
    state: disabled
- name: python_mod
  id: epy_module
  parameters:
    alias: ''
    comment: ''
    source_code: "# this module will be imported in the into your flowgraph\nf1=2380000000\n\
      f2=2420000000\nf=f1\nstep = 100000\n\ndef sweeper(prob_lvl):\n    global f1,f2,f,step\n\
      \    if prob_lvl:\n        f +=step\n    if f>f2:f=f1\n\n    return f"
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [848, 16.0]
    rotation: 0
    state: true
- name: qtgui_freq_sink_x_0
  id: qtgui_freq_sink_x
  parameters:
    affinity: ''
    alias: ''
    alpha1: '1.0'
    alpha10: '1.0'
    alpha2: '1.0'
    alpha3: '1.0'
    alpha4: '1.0'
    alpha5: '1.0'
    alpha6: '1.0'
    alpha7: '1.0'
    alpha8: '1.0'
    alpha9: '1.0'
    autoscale: 'False'
    average: '1.0'
    axislabels: 'True'
    bw: samp_rate
    color1: '"blue"'
    color10: '"dark blue"'
    color2: '"red"'
    color3: '"green"'
    color4: '"black"'
    color5: '"cyan"'
    color6: '"magenta"'
    color7: '"yellow"'
    color8: '"dark red"'
    color9: '"dark green"'
    comment: ''
    ctrlpanel: 'True'
    fc: freq
    fftsize: '1024'
    freqhalf: 'True'
    grid: 'False'
    gui_hint: ''
    label: Relative Gain
    label1: ''
    label10: ''''''
    label2: ''''''
    label3: ''''''
    label4: ''''''
    label5: ''''''
    label6: ''''''
    label7: ''''''
    label8: ''''''
    label9: ''''''
    legend: 'True'
    maxoutbuf: '0'
    minoutbuf: '0'
    name: '""'
    nconnections: '1'
    norm_window: 'False'
    showports: 'False'
    tr_chan: '0'
    tr_level: '0.0'
    tr_mode: qtgui.TRIG_MODE_FREE
    tr_tag: '""'
    type: complex
    units: dB
    update_time: '0.10'
    width1: '1'
    width10: '1'
    width2: '1'
    width3: '1'
    width4: '1'
    width5: '1'
    width6: '1'
    width7: '1'
    width8: '1'
    width9: '1'
    wintype: window.WIN_BLACKMAN_hARRIS
    ymax: '10'
    ymin: '-140'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1368, 188.0]
    rotation: 0
    state: enabled
- name: qtgui_time_sink_x_0
  id: qtgui_time_sink_x
  parameters:
    affinity: ''
    alias: ''
    alpha1: '1.0'
    alpha10: '1.0'
    alpha2: '1.0'
    alpha3: '1.0'
    alpha4: '1.0'
    alpha5: '1.0'
    alpha6: '1.0'
    alpha7: '1.0'
    alpha8: '1.0'
    alpha9: '1.0'
    autoscale: 'False'
    axislabels: 'True'
    color1: blue
    color10: dark blue
    color2: red
    color3: green
    color4: black
    color5: cyan
    color6: magenta
    color7: yellow
    color8: dark red
    color9: dark green
    comment: ''
    ctrlpanel: 'False'
    entags: 'True'
    grid: 'False'
    gui_hint: ''
    label1: Signal 1
    label10: Signal 10
    label2: Signal 2
    label3: Signal 3
    label4: Signal 4
    label5: Signal 5
    label6: Signal 6
    label7: Signal 7
    label8: Signal 8
    label9: Signal 9
    legend: 'True'
    marker1: '-1'
    marker10: '-1'
    marker2: '-1'
    marker3: '-1'
    marker4: '-1'
    marker5: '-1'
    marker6: '-1'
    marker7: '-1'
    marker8: '-1'
    marker9: '-1'
    name: '""'
    nconnections: '1'
    size: '1024'
    srate: samp_rate
    stemplot: 'False'
    style1: '1'
    style10: '1'
    style2: '1'
    style3: '1'
    style4: '1'
    style5: '1'
    style6: '1'
    style7: '1'
    style8: '1'
    style9: '1'
    tr_chan: '0'
    tr_delay: '0'
    tr_level: '0.0'
    tr_mode: qtgui.TRIG_MODE_FREE
    tr_slope: qtgui.TRIG_SLOPE_POS
    tr_tag: '""'
    type: complex
    update_time: '0.10'
    width1: '1'
    width10: '1'
    width2: '1'
    width3: '1'
    width4: '1'
    width5: '1'
    width6: '1'
    width7: '1'
    width8: '1'
    width9: '1'
    ylabel: Amplitude
    ymax: '1'
    ymin: '-1'
    yunit: '""'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [520, 308.0]
    rotation: 0
    state: disabled
- name: qtgui_vector_sink_f_0
  id: qtgui_vector_sink_f
  parameters:
    affinity: ''
    alias: ''
    alpha1: '1.0'
    alpha10: '1.0'
    alpha2: '1.0'
    alpha3: '1.0'
    alpha4: '1.0'
    alpha5: '1.0'
    alpha6: '1.0'
    alpha7: '1.0'
    alpha8: '1.0'
    alpha9: '1.0'
    autoscale: 'False'
    average: '1.0'
    color1: '"blue"'
    color10: '"dark blue"'
    color2: '"red"'
    color3: '"green"'
    color4: '"black"'
    color5: '"cyan"'
    color6: '"magenta"'
    color7: '"yellow"'
    color8: '"dark red"'
    color9: '"dark green"'
    comment: ''
    grid: 'False'
    gui_hint: ''
    label1: ''
    label10: ''
    label2: ''
    label3: ''
    label4: ''
    label5: ''
    label6: ''
    label7: ''
    label8: ''
    label9: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    name: '""'
    nconnections: '1'
    ref_level: '0'
    showports: 'False'
    update_time: '0.10'
    vlen: '1024'
    width1: '1'
    width10: '1'
    width2: '1'
    width3: '1'
    width4: '1'
    width5: '1'
    width6: '1'
    width7: '1'
    width8: '1'
    width9: '1'
    x_axis_label: '"x-Axis"'
    x_start: '0'
    x_step: '1.0'
    x_units: '""'
    y_axis_label: '"y-Axis"'
    y_units: '""'
    ymax: '10'
    ymin: '-140'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1384, 300.0]
    rotation: 0
    state: disabled
- name: uri
  id: parameter
  parameters:
    alias: ''
    comment: ''
    hide: none
    label: URI
    short_id: ''
    type: ''
    value: '"ip:192.168.2.1"'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1000, 4.0]
    rotation: 0
    state: enabled

connections:
- [analog_noise_source_x_0, '0', blocks_add_xx_0, '1']
- [analog_sig_source_x_0, '0', blocks_throttle_0, '0']
- [analog_sig_source_x_1, '0', blocks_add_xx_0, '0']
- [blocks_add_xx_0, '0', qtgui_freq_sink_x_0, '0']
- [blocks_throttle_0, '0', probSign1, '0']
- [blocks_throttle_0, '0', qtgui_time_sink_x_0, '0']
- [blocks_throttle_0_0, '0', logpwrfft_x_0, '0']
- [fft_vxx_0, '0', blocks_throttle_0_0, '0']
- [iio_pluto_source_0, '0', fft_vxx_0, '0']
- [iio_pluto_source_0, '0', probSign, '0']
- [iio_pluto_source_0, '0', qtgui_freq_sink_x_0, '0']
- [logpwrfft_x_0, '0', qtgui_vector_sink_f_0, '0']

metadata:
  file_format: 1

next is python_mod code

What is your dwell time requirement?

Note too that when you change frequency the data may not reflect the updated frequency as there is natural elasticity in the system. This delay would need to be measured.

-Travis

Kindly explain what do you mean by dwell time.

the user should be able to see the full spectrum of the sdr and the signal power for the frequency while it gets scanned and the scanning and display should be as fast as the capability of the sdr.

Please advise if this answers you queries to suggest a solution

Dwell time is how long you remain at one frequency.

-Travis

ok travis lets say 3 milli seconds that means the radio will be able to visit the same freq atlesst twict in a second for the bandwidth between 70 Mhz - 6 Ghz

Hope i am correct

Maybe I can frame this a bit for you. So in GNU Radio the way you are controlling frequency updates relative to the data stream is purely asynchronous. From the perspective of general software control of the LO frequency and data stream, they are asynchronous.  This creates a scenarios like I mentioned in a previous post:

travisfcollins said:

Note too that when you change frequency the data may not reflect the updated frequency as there is natural elasticity in the system. This delay would need to be measured

Without highly customizing the HDL and software control the only way to make sure the current data reflects the current desired frequency is to process say N buffers aka wait. N would take into account the GNU Radio inter-block buffers and the buffers libiio uses to stream data from hardware. By default the number of libiio buffers is 4 (size of buffers is set by the block). Getting the number of inline buffers in GNU Radio is complex since its managed by a scheduler. The hacky way to do this is to just make N large. Like >10+libiio buffers.

I would recommend verifying that your data reflects the desired frequency of interest. Say ping pong between 2 frequencies with known spectral content. Once that works you can scan the entire band of interest.

-Travis

Maybe I can frame this a bit for you. So in GNU Radio the way you are controlling frequency updates relative to the data stream is purely asynchronous. From the perspective of general software control of the LO frequency and data stream, they are asynchronous.  This creates a scenarios like I mentioned in a previous post:

travisfcollins said:

Note too that when you change frequency the data may not reflect the updated frequency as there is natural elasticity in the system. This delay would need to be measured

Without highly customizing the HDL and software control the only way to make sure the current data reflects the current desired frequency is to process say N buffers aka wait. N would take into account the GNU Radio inter-block buffers and the buffers libiio uses to stream data from hardware. By default the number of libiio buffers is 4 (size of buffers is set by the block). Getting the number of inline buffers in GNU Radio is complex since its managed by a scheduler. The hacky way to do this is to just make N large. Like >10+libiio buffers.

I would recommend verifying that your data reflects the desired frequency of interest. Say ping pong between 2 frequencies with known spectral content. Once that works you can scan the entire band of interest.

-Travis