lili/data-over-audio
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show number of frequencies for given fft size

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This commit is contained in:
Lewis Moten
2024-05-02 21:54:02 -04:00
parent 2bc4f9879d
commit 7e74355273
2 changed files with 12 additions and 2 deletions
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1
index.html
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@@ -16,6 +16,7 @@
Last Bit Percent: <input id="last-bit-percent" type="number" min="0" max="100" value="90">%<br>
FFT Size: 2^<input id="fft-size-power-text" type="number" min="5" max="15" value="90"><br>
Frequency Resolution: <span id="frequency-resolution">N/A</span><br>
Frequency Count: <span id="frequency-count">N/A</span><br>
Smoothing Time Constant: <input id="smoothing-time-constant-text" type="number" min="0.00" max="1.00" step="0.01" value="0.00"><br>
<input type="text" id="text-to-send">
<button id="send-button">Send</button>

13
index.js
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@@ -79,10 +79,10 @@ function handleWindowLoad() {
document.getElementById('fft-size-power-text').addEventListener('input', (event) => {
FFT_POWER = parseInt(event.target.value);
if(analyser) analyser.fftSize = 2 ** FFT_POWER;
document.getElementById('frequency-resolution').innerText = (getAudioContext().sampleRate / 2 ** FFT_POWER).toFixed(2);
updateFrequencyResolution();
resetGraphData();
});
document.getElementById('frequency-resolution').innerText = (getAudioContext().sampleRate / 2 ** FFT_POWER).toFixed(2);
updateFrequencyResolution();
document.getElementById('smoothing-time-constant-text').addEventListener('input', event => {
SMOOTHING_TIME_CONSTANT = parseFloat(event.target.value);
if(analyser) analyser.smoothingTimeConstant = SMOOTHING_TIME_CONSTANT;
@@ -95,6 +95,15 @@ function handleWindowLoad() {
showSpeed();
}
function updateFrequencyResolution() {
const sampleRate = getAudioContext().sampleRate;
const fftSize = 2 ** FFT_POWER;
const frequencyResolution = sampleRate / fftSize;
const frequencyCount = (sampleRate/2) / frequencyResolution;
document.getElementById('frequency-resolution').innerText = frequencyResolution.toFixed(2);
document.getElementById('frequency-count').innerText = frequencyCount.toFixed(2);
}
function showSpeed() {
const baud = 1000 / FREQUENCY_DURATION;
const bytes = baud / 8;