Challenge 1

Tune a tone to a target frequency and confirm it on the spectrum analyzer.

Author GNU Radio World
Category Gnuradio World Challenges
Blocks 12
Connections 4
File _gnuradio-world-challenges/challenge_1.grc

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Blocks used

Block	Module	Used
Variable	`GNU Radio`	3
Note	`GNU Radio`	2
Add	`GNU Radio`	1
Challenge	`GNU Radio`	1
GUI Layout	`GNU Radio`	1
Noise Source	`GNU Radio`	1
Signal Source	`GNU Radio`	1
Spectrum Analyzer	`GNU Radio`	1
Throttle	`GNU Radio`	1

Notes in this flowgraph

The radio is tuned to 100 MHz and listening across 1 MHz of spectrum, so the analyzer shows 99.5 MHz to 100.5 MHz. The Signal Source adds a tone at an offset from that center frequency.
Challenge: 1) Run the flowgraph and find the tone -- it starts at the center of the display 2) Put the tone at 100.25 MHz by changing the tone_offset variable The offset is relative to the center frequency, and a variable is edited the same way a block parameter is: double-click it.

Flowgraph source

_gnuradio-world-challenges/challenge_1.grc

options:
    parameters:
        author: GNU Radio World
        comment: ''
        copyright: ''
        description: Tune a tone to a target frequency and confirm it on the spectrum analyzer.
        generate_options: qt_gui
        id: Challenge_1
        title: Challenge 1
    states:
        coordinate: [10, 10]
        rotation: 0
        state: enabled
blocks:
-   name: center_freq
    id: variable
    parameters:
        comment: ''
        value: '100000000'
    states:
        coordinate: [590, 10]
        rotation: 0
        state: enabled
-   name: samp_rate
    id: variable
    parameters:
        comment: ''
        value: '1000000'
    states:
        coordinate: [760, 10]
        rotation: 0
        state: enabled
-   name: tone_offset
    id: variable
    parameters:
        comment: ''
        value: '0'
    states:
        coordinate: [930, 10]
        rotation: 0
        state: enabled
-   name: analyzer
    id: wasm_spectrum_analyzer_sink
    parameters:
        affinity: ''
        alias: ''
        average: '0.2'
        center_freq: center_freq
        comment: Finds and measures signals
        db_per_div: '10'
        fftsize: '4096'
        level_offset_db: '0'
        level_unit: dBFS
        name: Tune the tone
        reference_level: '0'
        samp_rate: samp_rate
        trace_mode: average
        type: complex
        update_time: '0.1'
        wintype: window.WIN_BLACKMAN_hARRIS
    states:
        coordinate: [940, 450]
        rotation: 0
        state: enabled
-   name: challenge_1
    id: wasm_challenge
    parameters:
        affinity: ''
        alias: ''
        challenge_id: challenge_1
        comment: ''
        criteria: "[\n {\"kind\": \"ran\", \"seconds\": 3, \"goal\": \"Run the flowgraph and find the tone on the spectrum\"},\n {\"kind\": \"detected_signal\", \"center_freq\": 100250000, \"center_tol\": 20000, \"min_peak_level\": -40, \"goal\": \"Move the tone to 100.25 MHz - 250 kHz above the center frequency\"}\n]"
        requires: challenge_0
        title: Tune the tone
    states:
        coordinate: [1100, 10]
        rotation: 0
        state: enabled
-   name: channel_sum
    id: blocks_add_xx
    parameters:
        affinity: ''
        alias: ''
        comment: ''
        maxoutbuf: '0'
        minoutbuf: '0'
        num_inputs: '2'
        type: complex
        vlen: '1'
    states:
        coordinate: [370, 530]
        rotation: 0
        state: enabled
-   name: channel_throttle
    id: blocks_throttle2
    parameters:
        affinity: ''
        alias: ''
        comment: "Limits the rate of IQ samples\nflowing through"
        ignoretag: 'True'
        limit: time
        maximum: '0.02'
        maxoutbuf: '0'
        minoutbuf: '0'
        samples_per_second: samp_rate
        type: complex
        vlen: '1'
    states:
        coordinate: [610, 520]
        rotation: 0
        state: enabled
-   name: gui_layout
    id: wasm_gui_layout
    parameters:
        affinity: ''
        alias: ''
        columns: '12'
        comment: ''
        layout: '{"analyzer":[0,0,12,8]}'
        row_height: '60'
    states:
        coordinate: [300, 10]
        rotation: 0
        state: enabled
-   name: note_0
    id: note
    parameters:
        affinity: ''
        alias: ''
        bgcolor: '#4dff6a'
        comment: ''
        note: The radio is tuned to 100 MHz and listening across 1 MHz of spectrum, so the analyzer shows 99.5 MHz to 100.5 MHz. The Signal Source adds a tone at an offset from that center frequency.
    states:
        coordinate: [10, 210]
        rotation: 0
        state: enabled
-   name: note_1
    id: note
    parameters:
        affinity: ''
        alias: ''
        bgcolor: '#4dff6a'
        comment: ''
        note: "Challenge:\n1) Run the flowgraph and find the tone -- it starts at the center of the display\n2) Put the tone at 100.25 MHz by changing the tone_offset variable\n\nThe offset is relative to the center frequency, and a variable is edited the same way a block parameter is: double-click it."
    states:
        coordinate: [420, 210]
        rotation: 0
        state: enabled
-   name: receiver_noise
    id: analog_noise_source_x
    parameters:
        affinity: ''
        alias: ''
        amp: '0.002'
        comment: Gives the detector a noise floor
        maxoutbuf: '0'
        minoutbuf: '0'
        noise_type: analog.GR_GAUSSIAN
        seed: '7'
        type: complex
    states:
        coordinate: [10, 670]
        rotation: 0
        state: enabled
-   name: tone
    id: analog_sig_source_x
    parameters:
        affinity: ''
        alias: ''
        amp: '0.3'
        comment: The tone you are moving
        freq: tone_offset
        maxoutbuf: '0'
        minoutbuf: '0'
        offset: '0'
        phase: '0'
        samp_rate: samp_rate
        type: complex
        waveform: analog.GR_COS_WAVE
    states:
        coordinate: [10, 490]
        rotation: 0
        state: enabled
connections:
- [channel_sum, '0', channel_throttle, '0']
- [channel_throttle, '0', analyzer, '0']
- [receiver_noise, '0', channel_sum, '1']
- [tone, '0', channel_sum, '0']
metadata:
    file_format: 1
    grc_version: 3.11.0.0