Strong signal at center frequence

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submarine
Posts: 1
Joined: Fri Sep 13, 2024 4:42 am

Strong signal at center frequence

Post by submarine »

Dear BladeRF users,

I am currently trying to send a a video signal between the rx and tx of a bladeRF xa9 using a gnuradio3.8 programm. The signal has a bandwidth of 8 MHz, however around the center of the signal there appears a strong peak in the signal, which should not be there according to the produced signal of the software. Maybe there is an issue with the bladeRF? Maybe the bladeRF needs to be callibrated?

I am providing some more informations:

Code: Select all

bladeRF> info

  Board:                    Nuand bladeRF 2.0 (bladerf2)
  Serial #:                 c43fc0a1e75040f595b839a77e0a5207
  VCTCXO DAC calibration:   0x1e29
  FPGA size:                301 KLE
  FPGA loaded:              yes
  Flash size:               128 Mbit
  USB bus:                  1
  USB address:              17
  USB speed:                Hi-Speed
  Backend:                  libusb
  Instance:                 0

Code: Select all

bladeRF> version

  bladeRF-cli version:        1.9.0-git-unknown
  libbladeRF version:         2.5.0-git-unknown

  Firmware version:           2.4.0-git-a3d5c55f
  FPGA version:               0.14.0 (configured from SPI flash)
Gnuradio Programm:

Code: Select all

options:
  parameters:
    author: malik
    category: '[GRC Hier Blocks]'
    cmake_opt: ''
    comment: ''
    copyright: ''
    description: ''
    gen_cmake: 'On'
    gen_linking: dynamic
    generate_options: qt_gui
    hier_block_src_path: '.:'
    id: dvbt_tx_rx
    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: Not titled yet
    window_size: (1000,1000)
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [8, 8]
    rotation: 0
    state: enabled

blocks:
- name: center_freq
  id: variable
  parameters:
    comment: ''
    value: 2.4e9
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [176, 60.0]
    rotation: 0
    state: enabled
- name: samp_rate
  id: variable
  parameters:
    comment: ''
    value: (8000000.0 * 8) / 7
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [176, 4.0]
    rotation: 0
    state: enabled
- name: tx_gain
  id: variable_qtgui_range
  parameters:
    comment: ''
    gui_hint: ''
    label: ''
    min_len: '200'
    orient: Qt.Horizontal
    rangeType: float
    start: '0'
    step: '1'
    stop: '89'
    value: '50'
    widget: counter_slider
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [232, 476.0]
    rotation: 0
    state: enabled
- name: vga1_gain
  id: variable_qtgui_range
  parameters:
    comment: ''
    gui_hint: ''
    label: ''
    min_len: '200'
    orient: Qt.Horizontal
    rangeType: int
    start: '-35'
    step: '1'
    stop: '-4'
    value: '-8'
    widget: counter_slider
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [0, 476.0]
    rotation: 0
    state: enabled
- name: vga2_gain
  id: variable_qtgui_range
  parameters:
    comment: ''
    gui_hint: ''
    label: ''
    min_len: '200'
    orient: Qt.Horizontal
    rangeType: int
    start: '0'
    step: '1'
    stop: '25'
    value: '10'
    widget: counter_slider
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [112, 476.0]
    rotation: 0
    state: enabled
- name: blocks_file_sink_0
  id: blocks_file_sink
  parameters:
    affinity: ''
    alias: ''
    append: 'False'
    comment: ''
    file: /home/nixos/Desktop/data/adv8dvbt23qam64_result.ts
    type: byte
    unbuffered: 'False'
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1408, 860.0]
    rotation: 0
    state: enabled
- name: blocks_file_source_0
  id: blocks_file_source
  parameters:
    affinity: ''
    alias: ''
    begin_tag: pmt.PMT_NIL
    comment: ''
    file: /home/nixos/Desktop/data/adv8dvbt23qam64.ts
    length: '0'
    maxoutbuf: '0'
    minoutbuf: '0'
    offset: '0'
    repeat: 'True'
    type: byte
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [344, 44.0]
    rotation: 0
    state: enabled
- name: blocks_multiply_const_xx_0
  id: blocks_multiply_const_xx
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    const: '0.0022097087'
    maxoutbuf: '0'
    minoutbuf: '0'
    type: complex
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [440, 476.0]
    rotation: 0
    state: enabled
- 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: [952, 284.0]
    rotation: 0
    state: true
- name: blocks_vector_to_stream_0
  id: blocks_vector_to_stream
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    num_items: '8192'
    type: complex
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [56, 304.0]
    rotation: 0
    state: enabled
- name: blocks_vector_to_stream_0_0
  id: blocks_vector_to_stream
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    num_items: '6048'
    type: complex
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1472, 528.0]
    rotation: 180
    state: enabled
- name: blocks_vector_to_stream_1
  id: blocks_vector_to_stream
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    num_items: '6048'
    type: byte
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [800, 608.0]
    rotation: 180
    state: enabled
- name: digital_ofdm_cyclic_prefixer_0
  id: digital_ofdm_cyclic_prefixer
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    cp_len: '256'
    input_size: '8192'
    maxoutbuf: '0'
    minoutbuf: '0'
    rolloff: '0'
    tagname: ''
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [416, 380.0]
    rotation: 0
    state: enabled
- name: dtv_dvbt_bit_inner_deinterleaver_0
  id: dtv_dvbt_bit_inner_deinterleaver
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    constellation: 64qam
    hierarchy: nh
    maxoutbuf: '0'
    minoutbuf: '0'
    transmission_mode: T8k
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [992, 588.0]
    rotation: 180
    state: enabled
- name: dtv_dvbt_bit_inner_interleaver_0
  id: dtv_dvbt_bit_inner_interleaver
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    constellation: 64qam
    hierarchy: nh
    maxoutbuf: '0'
    minoutbuf: '0'
    transmission_mode: T8k
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [880, 196.0]
    rotation: 180
    state: enabled
- name: dtv_dvbt_convolutional_deinterleaver_0
  id: dtv_dvbt_convolutional_deinterleaver
  parameters:
    I: '12'
    M: '17'
    affinity: ''
    alias: ''
    blocks: '136'
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1168, 692.0]
    rotation: 0
    state: enabled
- name: dtv_dvbt_convolutional_interleaver_0
  id: dtv_dvbt_convolutional_interleaver
  parameters:
    I: '12'
    M: '17'
    affinity: ''
    alias: ''
    blocks: '136'
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1144, 60.0]
    rotation: 0
    state: enabled
- name: dtv_dvbt_demap_0
  id: dtv_dvbt_demap
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    constellation: 64qam
    gain: '1'
    hierarchy: nh
    maxoutbuf: '0'
    minoutbuf: '0'
    transmission_mode: T8k
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1528, 572.0]
    rotation: 180
    state: enabled
- name: dtv_dvbt_demod_reference_signals_0
  id: dtv_dvbt_demod_reference_signals
  parameters:
    affinity: ''
    alias: ''
    cell_id: '0'
    code_rate_hp: C2_3
    code_rate_lp: C2_3
    comment: ''
    constellation: 64qam
    guard_interval: GI_1_32
    hierarchy: nh
    include_cell_id: call_id_yes
    maxoutbuf: '0'
    minoutbuf: '0'
    transmission_mode: T8k
    type: complex
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1632, 252.0]
    rotation: 0
    state: enabled
- name: dtv_dvbt_energy_descramble_0
  id: dtv_dvbt_energy_descramble
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    nsize: '8'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1128, 884.0]
    rotation: 0
    state: enabled
- name: dtv_dvbt_energy_dispersal_0
  id: dtv_dvbt_energy_dispersal
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    nsize: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [616, 76.0]
    rotation: 0
    state: enabled
- name: dtv_dvbt_inner_coder_0
  id: dtv_dvbt_inner_coder
  parameters:
    affinity: ''
    alias: ''
    code_rate: C2_3
    comment: ''
    constellation: 64qam
    hierarchy: nh
    maxoutbuf: '0'
    minoutbuf: '0'
    ninput: '1'
    noutput: '6048'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1128, 172.0]
    rotation: 180
    state: enabled
- name: dtv_dvbt_map_0
  id: dtv_dvbt_map
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    constellation: 64qam
    gain: '1'
    hierarchy: nh
    maxoutbuf: '0'
    minoutbuf: '0'
    transmission_mode: T8k
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [344, 180.0]
    rotation: 180
    state: enabled
- name: dtv_dvbt_ofdm_sym_acquisition_0
  id: dtv_dvbt_ofdm_sym_acquisition
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    cp_length: '256'
    fft_length: '8192'
    maxoutbuf: '0'
    minoutbuf: '0'
    occupied_tones: '6817'
    snr: '30'
    type: complex
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1152, 300.0]
    rotation: 0
    state: enabled
- name: dtv_dvbt_reed_solomon_dec_0
  id: dtv_dvbt_reed_solomon_dec
  parameters:
    affinity: ''
    alias: ''
    blocks: '8'
    comment: ''
    gfpoly: '0x11d'
    k: '239'
    m: '8'
    maxoutbuf: '0'
    minoutbuf: '0'
    n: '255'
    p: '2'
    s: '51'
    t: '8'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [888, 820.0]
    rotation: 0
    state: enabled
- name: dtv_dvbt_reed_solomon_enc_0
  id: dtv_dvbt_reed_solomon_enc
  parameters:
    affinity: ''
    alias: ''
    blocks: '8'
    comment: ''
    gfpoly: '0x11d'
    k: '239'
    m: '8'
    maxoutbuf: '0'
    minoutbuf: '0'
    n: '255'
    p: '2'
    s: '51'
    t: '8'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [872, 20.0]
    rotation: 0
    state: enabled
- name: dtv_dvbt_reference_signals_0
  id: dtv_dvbt_reference_signals
  parameters:
    affinity: ''
    alias: ''
    cell_id: '0'
    code_rate_hp: C2_3
    code_rate_lp: C2_3
    comment: ''
    constellation: 64qam
    guard_interval: GI_1_32
    hierarchy: nh
    include_cell_id: call_id_yes
    maxoutbuf: '0'
    minoutbuf: '0'
    transmission_mode: T8k
    type: complex
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [56, 124.0]
    rotation: 180
    state: enabled
- name: dtv_dvbt_symbol_inner_interleaver_0
  id: dtv_dvbt_symbol_inner_interleaver
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    direction: Interleave
    maxoutbuf: '0'
    minoutbuf: '0'
    transmission_mode: T8k
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [624, 196.0]
    rotation: 180
    state: enabled
- name: dtv_dvbt_symbol_inner_interleaver_0_0
  id: dtv_dvbt_symbol_inner_interleaver
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    direction: Deinterleave
    maxoutbuf: '0'
    minoutbuf: '0'
    transmission_mode: T8k
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1264, 596.0]
    rotation: 180
    state: enabled
- name: dtv_dvbt_viterbi_decoder_0
  id: dtv_dvbt_viterbi_decoder
  parameters:
    affinity: ''
    alias: ''
    block_size: '768'
    code_rate: C2_3
    comment: ''
    constellation: 64qam
    hierarchy: nh
    maxoutbuf: '0'
    minoutbuf: '0'
    type: b
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [736, 700.0]
    rotation: 0
    state: enabled
- name: fft_vxx_0
  id: fft_vxx
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    fft_size: '8192'
    forward: 'False'
    maxoutbuf: '0'
    minoutbuf: '0'
    nthreads: '1'
    shift: 'True'
    type: complex
    window: window.rectangular(8192)
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [56, 336.0]
    rotation: 0
    state: enabled
- name: fft_vxx_0_0
  id: fft_vxx
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    fft_size: '8192'
    forward: 'True'
    maxoutbuf: '0'
    minoutbuf: '0'
    nthreads: '1'
    shift: 'True'
    type: complex
    window: window.rectangular(8192)
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1384, 292.0]
    rotation: 0
    state: enabled
- name: osmosdr_sink_0
  id: osmosdr_sink
  parameters:
    affinity: ''
    alias: ''
    ant0: ''
    ant1: ''
    ant10: ''
    ant11: ''
    ant12: ''
    ant13: ''
    ant14: ''
    ant15: ''
    ant16: ''
    ant17: ''
    ant18: ''
    ant19: ''
    ant2: ''
    ant20: ''
    ant21: ''
    ant22: ''
    ant23: ''
    ant24: ''
    ant25: ''
    ant26: ''
    ant27: ''
    ant28: ''
    ant29: ''
    ant3: ''
    ant30: ''
    ant31: ''
    ant4: ''
    ant5: ''
    ant6: ''
    ant7: ''
    ant8: ''
    ant9: ''
    args: bladerf=0,biastee=1
    bb_gain0: '20'
    bb_gain1: '20'
    bb_gain10: '20'
    bb_gain11: '20'
    bb_gain12: '20'
    bb_gain13: '20'
    bb_gain14: '20'
    bb_gain15: '20'
    bb_gain16: '20'
    bb_gain17: '20'
    bb_gain18: '20'
    bb_gain19: '20'
    bb_gain2: '20'
    bb_gain20: '20'
    bb_gain21: '20'
    bb_gain22: '20'
    bb_gain23: '20'
    bb_gain24: '20'
    bb_gain25: '20'
    bb_gain26: '20'
    bb_gain27: '20'
    bb_gain28: '20'
    bb_gain29: '20'
    bb_gain3: '20'
    bb_gain30: '20'
    bb_gain31: '20'
    bb_gain4: '20'
    bb_gain5: '20'
    bb_gain6: '20'
    bb_gain7: '20'
    bb_gain8: '20'
    bb_gain9: '20'
    bw0: '0'
    bw1: '0'
    bw10: '0'
    bw11: '0'
    bw12: '0'
    bw13: '0'
    bw14: '0'
    bw15: '0'
    bw16: '0'
    bw17: '0'
    bw18: '0'
    bw19: '0'
    bw2: '0'
    bw20: '0'
    bw21: '0'
    bw22: '0'
    bw23: '0'
    bw24: '0'
    bw25: '0'
    bw26: '0'
    bw27: '0'
    bw28: '0'
    bw29: '0'
    bw3: '0'
    bw30: '0'
    bw31: '0'
    bw4: '0'
    bw5: '0'
    bw6: '0'
    bw7: '0'
    bw8: '0'
    bw9: '0'
    clock_source0: ''
    clock_source1: ''
    clock_source2: ''
    clock_source3: ''
    clock_source4: ''
    clock_source5: ''
    clock_source6: ''
    clock_source7: ''
    comment: ''
    corr0: '0'
    corr1: '0'
    corr10: '0'
    corr11: '0'
    corr12: '0'
    corr13: '0'
    corr14: '0'
    corr15: '0'
    corr16: '0'
    corr17: '0'
    corr18: '0'
    corr19: '0'
    corr2: '0'
    corr20: '0'
    corr21: '0'
    corr22: '0'
    corr23: '0'
    corr24: '0'
    corr25: '0'
    corr26: '0'
    corr27: '0'
    corr28: '0'
    corr29: '0'
    corr3: '0'
    corr30: '0'
    corr31: '0'
    corr4: '0'
    corr5: '0'
    corr6: '0'
    corr7: '0'
    corr8: '0'
    corr9: '0'
    freq0: center_freq
    freq1: 100e6
    freq10: 100e6
    freq11: 100e6
    freq12: 100e6
    freq13: 100e6
    freq14: 100e6
    freq15: 100e6
    freq16: 100e6
    freq17: 100e6
    freq18: 100e6
    freq19: 100e6
    freq2: 100e6
    freq20: 100e6
    freq21: 100e6
    freq22: 100e6
    freq23: 100e6
    freq24: 100e6
    freq25: 100e6
    freq26: 100e6
    freq27: 100e6
    freq28: 100e6
    freq29: 100e6
    freq3: 100e6
    freq30: 100e6
    freq31: 100e6
    freq4: 100e6
    freq5: 100e6
    freq6: 100e6
    freq7: 100e6
    freq8: 100e6
    freq9: 100e6
    gain0: '10'
    gain1: '10'
    gain10: '10'
    gain11: '10'
    gain12: '10'
    gain13: '10'
    gain14: '10'
    gain15: '10'
    gain16: '10'
    gain17: '10'
    gain18: '10'
    gain19: '10'
    gain2: '10'
    gain20: '10'
    gain21: '10'
    gain22: '10'
    gain23: '10'
    gain24: '10'
    gain25: '10'
    gain26: '10'
    gain27: '10'
    gain28: '10'
    gain29: '10'
    gain3: '10'
    gain30: '10'
    gain31: '10'
    gain4: '10'
    gain5: '10'
    gain6: '10'
    gain7: '10'
    gain8: '10'
    gain9: '10'
    if_gain0: '20'
    if_gain1: '20'
    if_gain10: '20'
    if_gain11: '20'
    if_gain12: '20'
    if_gain13: '20'
    if_gain14: '20'
    if_gain15: '20'
    if_gain16: '20'
    if_gain17: '20'
    if_gain18: '20'
    if_gain19: '20'
    if_gain2: '20'
    if_gain20: '20'
    if_gain21: '20'
    if_gain22: '20'
    if_gain23: '20'
    if_gain24: '20'
    if_gain25: '20'
    if_gain26: '20'
    if_gain27: '20'
    if_gain28: '20'
    if_gain29: '20'
    if_gain3: '20'
    if_gain30: '20'
    if_gain31: '20'
    if_gain4: '20'
    if_gain5: '20'
    if_gain6: '20'
    if_gain7: '20'
    if_gain8: '20'
    if_gain9: '20'
    maxoutbuf: '0'
    minoutbuf: '0'
    nchan: '1'
    num_mboards: '1'
    sample_rate: samp_rate
    sync: sync
    time_source0: ''
    time_source1: ''
    time_source2: ''
    time_source3: ''
    time_source4: ''
    time_source5: ''
    time_source6: ''
    time_source7: ''
    type: fc32
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [432, 572.0]
    rotation: 0
    state: true
- name: osmosdr_source_0
  id: osmosdr_source
  parameters:
    affinity: ''
    alias: ''
    ant0: ''
    ant1: ''
    ant10: ''
    ant11: ''
    ant12: ''
    ant13: ''
    ant14: ''
    ant15: ''
    ant16: ''
    ant17: ''
    ant18: ''
    ant19: ''
    ant2: ''
    ant20: ''
    ant21: ''
    ant22: ''
    ant23: ''
    ant24: ''
    ant25: ''
    ant26: ''
    ant27: ''
    ant28: ''
    ant29: ''
    ant3: ''
    ant30: ''
    ant31: ''
    ant4: ''
    ant5: ''
    ant6: ''
    ant7: ''
    ant8: ''
    ant9: ''
    args: bladerf=0,biastee=1
    bb_gain0: '20'
    bb_gain1: '20'
    bb_gain10: '20'
    bb_gain11: '20'
    bb_gain12: '20'
    bb_gain13: '20'
    bb_gain14: '20'
    bb_gain15: '20'
    bb_gain16: '20'
    bb_gain17: '20'
    bb_gain18: '20'
    bb_gain19: '20'
    bb_gain2: '20'
    bb_gain20: '20'
    bb_gain21: '20'
    bb_gain22: '20'
    bb_gain23: '20'
    bb_gain24: '20'
    bb_gain25: '20'
    bb_gain26: '20'
    bb_gain27: '20'
    bb_gain28: '20'
    bb_gain29: '20'
    bb_gain3: '20'
    bb_gain30: '20'
    bb_gain31: '20'
    bb_gain4: '20'
    bb_gain5: '20'
    bb_gain6: '20'
    bb_gain7: '20'
    bb_gain8: '20'
    bb_gain9: '20'
    bw0: '0'
    bw1: '0'
    bw10: '0'
    bw11: '0'
    bw12: '0'
    bw13: '0'
    bw14: '0'
    bw15: '0'
    bw16: '0'
    bw17: '0'
    bw18: '0'
    bw19: '0'
    bw2: '0'
    bw20: '0'
    bw21: '0'
    bw22: '0'
    bw23: '0'
    bw24: '0'
    bw25: '0'
    bw26: '0'
    bw27: '0'
    bw28: '0'
    bw29: '0'
    bw3: '0'
    bw30: '0'
    bw31: '0'
    bw4: '0'
    bw5: '0'
    bw6: '0'
    bw7: '0'
    bw8: '0'
    bw9: '0'
    clock_source0: ''
    clock_source1: ''
    clock_source2: ''
    clock_source3: ''
    clock_source4: ''
    clock_source5: ''
    clock_source6: ''
    clock_source7: ''
    comment: ''
    corr0: '0'
    corr1: '0'
    corr10: '0'
    corr11: '0'
    corr12: '0'
    corr13: '0'
    corr14: '0'
    corr15: '0'
    corr16: '0'
    corr17: '0'
    corr18: '0'
    corr19: '0'
    corr2: '0'
    corr20: '0'
    corr21: '0'
    corr22: '0'
    corr23: '0'
    corr24: '0'
    corr25: '0'
    corr26: '0'
    corr27: '0'
    corr28: '0'
    corr29: '0'
    corr3: '0'
    corr30: '0'
    corr31: '0'
    corr4: '0'
    corr5: '0'
    corr6: '0'
    corr7: '0'
    corr8: '0'
    corr9: '0'
    dc_offset_mode0: '0'
    dc_offset_mode1: '0'
    dc_offset_mode10: '0'
    dc_offset_mode11: '0'
    dc_offset_mode12: '0'
    dc_offset_mode13: '0'
    dc_offset_mode14: '0'
    dc_offset_mode15: '0'
    dc_offset_mode16: '0'
    dc_offset_mode17: '0'
    dc_offset_mode18: '0'
    dc_offset_mode19: '0'
    dc_offset_mode2: '0'
    dc_offset_mode20: '0'
    dc_offset_mode21: '0'
    dc_offset_mode22: '0'
    dc_offset_mode23: '0'
    dc_offset_mode24: '0'
    dc_offset_mode25: '0'
    dc_offset_mode26: '0'
    dc_offset_mode27: '0'
    dc_offset_mode28: '0'
    dc_offset_mode29: '0'
    dc_offset_mode3: '0'
    dc_offset_mode30: '0'
    dc_offset_mode31: '0'
    dc_offset_mode4: '0'
    dc_offset_mode5: '0'
    dc_offset_mode6: '0'
    dc_offset_mode7: '0'
    dc_offset_mode8: '0'
    dc_offset_mode9: '0'
    freq0: center_freq
    freq1: 100e6
    freq10: 100e6
    freq11: 100e6
    freq12: 100e6
    freq13: 100e6
    freq14: 100e6
    freq15: 100e6
    freq16: 100e6
    freq17: 100e6
    freq18: 100e6
    freq19: 100e6
    freq2: 100e6
    freq20: 100e6
    freq21: 100e6
    freq22: 100e6
    freq23: 100e6
    freq24: 100e6
    freq25: 100e6
    freq26: 100e6
    freq27: 100e6
    freq28: 100e6
    freq29: 100e6
    freq3: 100e6
    freq30: 100e6
    freq31: 100e6
    freq4: 100e6
    freq5: 100e6
    freq6: 100e6
    freq7: 100e6
    freq8: 100e6
    freq9: 100e6
    gain0: '10'
    gain1: '10'
    gain10: '10'
    gain11: '10'
    gain12: '10'
    gain13: '10'
    gain14: '10'
    gain15: '10'
    gain16: '10'
    gain17: '10'
    gain18: '10'
    gain19: '10'
    gain2: '10'
    gain20: '10'
    gain21: '10'
    gain22: '10'
    gain23: '10'
    gain24: '10'
    gain25: '10'
    gain26: '10'
    gain27: '10'
    gain28: '10'
    gain29: '10'
    gain3: '10'
    gain30: '10'
    gain31: '10'
    gain4: '10'
    gain5: '10'
    gain6: '10'
    gain7: '10'
    gain8: '10'
    gain9: '10'
    gain_mode0: 'False'
    gain_mode1: 'False'
    gain_mode10: 'False'
    gain_mode11: 'False'
    gain_mode12: 'False'
    gain_mode13: 'False'
    gain_mode14: 'False'
    gain_mode15: 'False'
    gain_mode16: 'False'
    gain_mode17: 'False'
    gain_mode18: 'False'
    gain_mode19: 'False'
    gain_mode2: 'False'
    gain_mode20: 'False'
    gain_mode21: 'False'
    gain_mode22: 'False'
    gain_mode23: 'False'
    gain_mode24: 'False'
    gain_mode25: 'False'
    gain_mode26: 'False'
    gain_mode27: 'False'
    gain_mode28: 'False'
    gain_mode29: 'False'
    gain_mode3: 'False'
    gain_mode30: 'False'
    gain_mode31: 'False'
    gain_mode4: 'False'
    gain_mode5: 'False'
    gain_mode6: 'False'
    gain_mode7: 'False'
    gain_mode8: 'False'
    gain_mode9: 'False'
    if_gain0: '20'
    if_gain1: '20'
    if_gain10: '20'
    if_gain11: '20'
    if_gain12: '20'
    if_gain13: '20'
    if_gain14: '20'
    if_gain15: '20'
    if_gain16: '20'
    if_gain17: '20'
    if_gain18: '20'
    if_gain19: '20'
    if_gain2: '20'
    if_gain20: '20'
    if_gain21: '20'
    if_gain22: '20'
    if_gain23: '20'
    if_gain24: '20'
    if_gain25: '20'
    if_gain26: '20'
    if_gain27: '20'
    if_gain28: '20'
    if_gain29: '20'
    if_gain3: '20'
    if_gain30: '20'
    if_gain31: '20'
    if_gain4: '20'
    if_gain5: '20'
    if_gain6: '20'
    if_gain7: '20'
    if_gain8: '20'
    if_gain9: '20'
    iq_balance_mode0: '0'
    iq_balance_mode1: '0'
    iq_balance_mode10: '0'
    iq_balance_mode11: '0'
    iq_balance_mode12: '0'
    iq_balance_mode13: '0'
    iq_balance_mode14: '0'
    iq_balance_mode15: '0'
    iq_balance_mode16: '0'
    iq_balance_mode17: '0'
    iq_balance_mode18: '0'
    iq_balance_mode19: '0'
    iq_balance_mode2: '0'
    iq_balance_mode20: '0'
    iq_balance_mode21: '0'
    iq_balance_mode22: '0'
    iq_balance_mode23: '0'
    iq_balance_mode24: '0'
    iq_balance_mode25: '0'
    iq_balance_mode26: '0'
    iq_balance_mode27: '0'
    iq_balance_mode28: '0'
    iq_balance_mode29: '0'
    iq_balance_mode3: '0'
    iq_balance_mode30: '0'
    iq_balance_mode31: '0'
    iq_balance_mode4: '0'
    iq_balance_mode5: '0'
    iq_balance_mode6: '0'
    iq_balance_mode7: '0'
    iq_balance_mode8: '0'
    iq_balance_mode9: '0'
    maxoutbuf: '0'
    minoutbuf: '0'
    nchan: '1'
    num_mboards: '1'
    sample_rate: samp_rate
    sync: sync
    time_source0: ''
    time_source1: ''
    time_source2: ''
    time_source3: ''
    time_source4: ''
    time_source5: ''
    time_source6: ''
    time_source7: ''
    type: fc32
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [696, 324.0]
    rotation: 0
    state: true
- name: qtgui_const_sink_x_0
  id: qtgui_const_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: '"red"'
    color2: '"red"'
    color3: '"red"'
    color4: '"red"'
    color5: '"red"'
    color6: '"red"'
    color7: '"red"'
    color8: '"red"'
    color9: '"red"'
    comment: ''
    grid: 'False'
    gui_hint: ''
    label1: ''
    label10: ''
    label2: ''
    label3: ''
    label4: ''
    label5: ''
    label6: ''
    label7: ''
    label8: ''
    label9: ''
    legend: 'True'
    marker1: '0'
    marker10: '0'
    marker2: '0'
    marker3: '0'
    marker4: '0'
    marker5: '0'
    marker6: '0'
    marker7: '0'
    marker8: '0'
    marker9: '0'
    name: Tx
    nconnections: '1'
    size: '1024'
    style1: '0'
    style10: '0'
    style2: '0'
    style3: '0'
    style4: '0'
    style5: '0'
    style6: '0'
    style7: '0'
    style8: '0'
    style9: '0'
    tr_chan: '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'
    xmax: '2'
    xmin: '-2'
    ymax: '2'
    ymin: '-2'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [416, 292.0]
    rotation: 0
    state: enabled
- name: qtgui_const_sink_x_0_0
  id: qtgui_const_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: 'True'
    axislabels: 'True'
    color1: '"blue"'
    color10: '"red"'
    color2: '"red"'
    color3: '"red"'
    color4: '"red"'
    color5: '"red"'
    color6: '"red"'
    color7: '"red"'
    color8: '"red"'
    color9: '"red"'
    comment: ''
    grid: 'False'
    gui_hint: ''
    label1: ''
    label10: ''
    label2: ''
    label3: ''
    label4: ''
    label5: ''
    label6: ''
    label7: ''
    label8: ''
    label9: ''
    legend: 'True'
    marker1: '0'
    marker10: '0'
    marker2: '0'
    marker3: '0'
    marker4: '0'
    marker5: '0'
    marker6: '0'
    marker7: '0'
    marker8: '0'
    marker9: '0'
    name: '""'
    nconnections: '1'
    size: '1024'
    style1: '0'
    style10: '0'
    style2: '0'
    style3: '0'
    style4: '0'
    style5: '0'
    style6: '0'
    style7: '0'
    style8: '0'
    style9: '0'
    tr_chan: '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'
    xmax: '1.5'
    xmin: '-1.5'
    ymax: '1.5'
    ymin: '-1.5'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1192, 524.0]
    rotation: 180
    state: enabled
- 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: '0.2'
    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: 'False'
    fc: center_freq
    fftsize: '1024'
    freqhalf: 'True'
    grid: 'True'
    gui_hint: ''
    label: Relative Gain
    label1: ''
    label10: ''
    label2: ''
    label3: ''
    label4: ''
    label5: ''
    label6: ''
    label7: ''
    label8: ''
    label9: ''
    legend: 'True'
    maxoutbuf: '0'
    minoutbuf: '0'
    name: Rx
    nconnections: '1'
    showports: 'True'
    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: firdes.WIN_BLACKMAN_hARRIS
    ymax: '-10'
    ymin: '-170'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [1152, 408.0]
    rotation: 0
    state: enabled

connections:
- [blocks_file_source_0, '0', dtv_dvbt_energy_dispersal_0, '0']
- [blocks_multiply_const_xx_0, '0', osmosdr_sink_0, '0']
- [blocks_throttle_0, '0', dtv_dvbt_ofdm_sym_acquisition_0, '0']
- [blocks_throttle_0, '0', qtgui_freq_sink_x_0, '0']
- [blocks_vector_to_stream_0, '0', qtgui_const_sink_x_0, '0']
- [blocks_vector_to_stream_0_0, '0', qtgui_const_sink_x_0_0, '0']
- [blocks_vector_to_stream_1, '0', dtv_dvbt_viterbi_decoder_0, '0']
- [digital_ofdm_cyclic_prefixer_0, '0', blocks_multiply_const_xx_0, '0']
- [dtv_dvbt_bit_inner_deinterleaver_0, '0', blocks_vector_to_stream_1, '0']
- [dtv_dvbt_bit_inner_interleaver_0, '0', dtv_dvbt_symbol_inner_interleaver_0, '0']
- [dtv_dvbt_convolutional_deinterleaver_0, '0', dtv_dvbt_reed_solomon_dec_0, '0']
- [dtv_dvbt_convolutional_interleaver_0, '0', dtv_dvbt_inner_coder_0, '0']
- [dtv_dvbt_demap_0, '0', dtv_dvbt_symbol_inner_interleaver_0_0, '0']
- [dtv_dvbt_demod_reference_signals_0, '0', blocks_vector_to_stream_0_0, '0']
- [dtv_dvbt_demod_reference_signals_0, '0', dtv_dvbt_demap_0, '0']
- [dtv_dvbt_energy_descramble_0, '0', blocks_file_sink_0, '0']
- [dtv_dvbt_energy_dispersal_0, '0', dtv_dvbt_reed_solomon_enc_0, '0']
- [dtv_dvbt_inner_coder_0, '0', dtv_dvbt_bit_inner_interleaver_0, '0']
- [dtv_dvbt_map_0, '0', dtv_dvbt_reference_signals_0, '0']
- [dtv_dvbt_ofdm_sym_acquisition_0, '0', fft_vxx_0_0, '0']
- [dtv_dvbt_reed_solomon_dec_0, '0', dtv_dvbt_energy_descramble_0, '0']
- [dtv_dvbt_reed_solomon_enc_0, '0', dtv_dvbt_convolutional_interleaver_0, '0']
- [dtv_dvbt_reference_signals_0, '0', blocks_vector_to_stream_0, '0']
- [dtv_dvbt_reference_signals_0, '0', fft_vxx_0, '0']
- [dtv_dvbt_symbol_inner_interleaver_0, '0', dtv_dvbt_map_0, '0']
- [dtv_dvbt_symbol_inner_interleaver_0_0, '0', dtv_dvbt_bit_inner_deinterleaver_0,
  '0']
- [dtv_dvbt_viterbi_decoder_0, '0', dtv_dvbt_convolutional_deinterleaver_0, '0']
- [fft_vxx_0, '0', digital_ofdm_cyclic_prefixer_0, '0']
- [fft_vxx_0_0, '0', dtv_dvbt_demod_reference_signals_0, '0']
- [osmosdr_source_0, '0', blocks_throttle_0, '0']

metadata:
  file_format: 1
Is there no method to upload files within this questions, so I need to post the content of the gnuradio file?
I would like to show you some pictures from the waterfall sink and I also would like to upload the needed example video file which shall be transmitted. How can I upload a file here? :)

Thanks a lot for helping me and all the best,

Jens
[email protected]
Posts: 7
Joined: Fri May 20, 2022 4:42 pm

Re: Strong signal at center frequence

Post by [email protected] »

Because this is a direct-to-baseband conversion device your center frequency is converted down to DC, and 1/f noise generates that spike, also referred to as DC offset. I minimize that in my ham-radio endeavors by tuning my center frequency off of my signal of interest by a small amount. But the AD9361 supposedly has a system to try to keep the DC offset nulled out, and if you are using the gr-bladeRF blocks in gnuradio you might find some options to make sure that the offset correction is enabled.
smithcohn12
Posts: 1
Joined: Thu Oct 10, 2024 2:06 am

Re: Strong signal at center frequence

Post by smithcohn12 »

It sounds like the strong peak at the center frequency could be caused by DC offset or I/Q imbalance, which is common in SDRs like the bladeRF. Try enabling DC offset correction or calibrating the bladeRF using the built-in calibration utilities to reduce or eliminate the center peak.
michaelarrington
Posts: 1
Joined: Sun Oct 13, 2024 7:29 pm

Re: Strong signal at center frequence

Post by michaelarrington »

[email protected] wrote: Wed Sep 18, 2024 8:55 pm Because this is a direct-to-baseband conversion device your center frequency is converted down to DC, and 1/f noise generates that spike, also referred to as DC offset. I minimize that in my ham-radio endeavors by tuning my center frequency off of my signal of interest by a small amount. But the AD9361 supposedly has a system to try to keep the DC offset nulled out, and if you are using the gr-bladeRF blocks in gnuradio you might find some options to make sure that the offset correction is enabled. Tunnel Rush


Check the gain settings on both the RX and TX sides. If the gain is set too high, it can lead to non-linearities and distortion, causing unwanted peaks in your signal.
suffixdrowsy
Posts: 1
Joined: Tue Oct 22, 2024 12:37 am
Location: United States
Contact:

Re: Strong signal at center frequence

Post by suffixdrowsy »

Many radio front ends, including the bladeRF, can introduce a DC offset that results in a peak at the center frequency. This is a common issue with direct conversion receivers.
Post Reply