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<head>
<title>Test Biquad Tail-Time</title>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="../resources/audit-util.js"></script>
<script src="../resources/audit.js"></script>
<script src="../resources/biquad-filters.js"></script>
<script src="test-tail-time.js"></script>
</head>
<body>
<script>
let audit = Audit.createTaskRunner();
let sampleRate = 16384;
let renderSeconds = 1;
let renderFrames = renderSeconds * sampleRate;
// For a bandpass filter:
// b0 = alpha
// b1 = 0
// b2 = -alpha
// a0 = 1 + alpha
// a1 = -2*cos(w0)
// a2 = 1 - alpha
//
// where alpha = sin(w0)/(2*Q) and w0 = 2*%pi*f0/Fs.
//
// Equivalently a1 = -2*cos(w0)/(1+alpha), a2 = (1-alpha)/(1+alpha). The
// poles of this filter are at
//
// (2*Q*cos(w0) +/- sqrt(1-4*Q^2)*sin(w0))/(2*Q + sin(w0))
//
// Thus, if 1-4*Q^2 < 0, the poles are complex. For 1-4*Q^2 > 0, the
// poles are real and distinct. For 1-4*Q^2 = 0, there are two identical
// real poles.
// Array of tests to run. |descripton| is the task description for
// audit.define. |parameters| is option for |testTailTime|.
let tests = [
{
descripton:
{label: 'bpf-complex-roots', description: 'complex roots'},
parameters: {
prefix: 'BPF complex roots',
filterOptions:
{type: 'bandpass', Q: 200, frequency: sampleRate / 4},
// The node estimated tail frame is 2039.55, which matches the
// true tail frame so output should be exactly 0
threshold: 0
}
},
{
descripton: {
label: 'bpf-real-distinct-roots',
description: 'real distinct roots'
},
parameters: {
prefix: 'BPF real distinct roots',
filterOptions:
{type: 'bandpass', Q: 0.001, frequency: sampleRate / 4},
// The node estimated tail frame is 2437, which matches the
// true tail frame so output should be exactly 0
threshold: 0
}
},
{
descripton:
{label: 'bpf-repeated-roots', description: 'repeated real root'},
parameters: {
prefix: 'BPF repeated roots',
filterOptions:
{type: 'bandpass', Q: 0.5, frequency: sampleRate / 8},
// The node estimated tail frame is 15.9, which matches the true
// tail frame so output should be exactly 0
threshold: 0
}
}
];
// Define an appropriate task for each test.
tests.forEach(entry => {
audit.define(entry.descripton, (task, should) => {
let context = new OfflineAudioContext(1, renderFrames, sampleRate);
testTailTime(should, context, entry.parameters)
.then(() => task.done());
});
});
audit.run();
</script>
</body>
</html>