mathjs
Version:
Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif
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JavaScript
;
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.createFreqz = void 0;
var _factory = require("../../utils/factory.js");
var name = 'freqz';
var dependencies = ['typed', 'add', 'multiply', 'Complex', 'divide', 'matrix'];
var createFreqz = exports.createFreqz = /* #__PURE__ */(0, _factory.factory)(name, dependencies, function (_ref) {
var typed = _ref.typed,
add = _ref.add,
multiply = _ref.multiply,
Complex = _ref.Complex,
divide = _ref.divide,
matrix = _ref.matrix;
/**
* Calculates the frequency response of a filter given its numerator and denominator coefficients.
*
* Syntax:
* math.freqz(b, a)
* math.freqz(b, a, w)
*
* Examples:
* math.freqz([1, 2], [1, 2, 3], 4) // returns { h: [0.5 + 0i, 0.4768589245763655 + 0.2861153547458193i, 0.25000000000000006 + 0.75i, -0.770976571635189 + 0.4625859429811135i], w: [0, 0.7853981633974483, 1.5707963267948966, 2.356194490192345 ] }
* math.freqz([1, 2], [1, 2, 3], [0, 1]) // returns { h: [0.5 + 0i, 0.45436781 + 0.38598051i], w: [0, 1] }
*
* See also:
* zpk2tf
*
* @param {Array.<number>} b The numerator coefficients of the filter.
* @param {Array.<number>} a The denominator coefficients of the filter.
* @param {Array.<number>} [w] A vector of frequencies (in radians/sample) at which the frequency response is to be computed or the number of points to compute (if a number is not provided, the default is 512 points)
* @returns {Object} An object with two properties: h, a vector containing the complex frequency response, and w, a vector containing the normalized frequencies (in radians/sample) at which the response was computed.
*
*
*/
return typed(name, {
'Array, Array': function ArrayArray(b, a) {
var w = createBins(512);
return _freqz(b, a, w);
},
'Array, Array, Array': function ArrayArrayArray(b, a, w) {
return _freqz(b, a, w);
},
'Array, Array, number': function ArrayArrayNumber(b, a, w) {
if (w < 0) {
throw new Error('w must be a positive number');
}
var w2 = createBins(w);
return _freqz(b, a, w2);
},
'Matrix, Matrix': function MatrixMatrix(b, a) {
// console.log('here')
var _w = createBins(512);
var _freqz2 = _freqz(b.valueOf(), a.valueOf(), _w),
w = _freqz2.w,
h = _freqz2.h;
return {
w: matrix(w),
h: matrix(h)
};
},
'Matrix, Matrix, Matrix': function MatrixMatrixMatrix(b, a, w) {
var _freqz3 = _freqz(b.valueOf(), a.valueOf(), w.valueOf()),
h = _freqz3.h;
return {
h: matrix(h),
w: matrix(w)
};
},
'Matrix, Matrix, number': function MatrixMatrixNumber(b, a, w) {
if (w < 0) {
throw new Error('w must be a positive number');
}
var _w = createBins(w);
var _freqz4 = _freqz(b.valueOf(), a.valueOf(), _w),
h = _freqz4.h;
return {
h: matrix(h),
w: matrix(_w)
};
}
});
function _freqz(b, a, w) {
var num = [];
var den = [];
for (var i = 0; i < w.length; i++) {
var sumNum = Complex(0, 0);
var sumDen = Complex(0, 0);
for (var j = 0; j < b.length; j++) {
sumNum = add(sumNum, multiply(b[j], Complex(Math.cos(-j * w[i]), Math.sin(-j * w[i]))));
}
for (var _j = 0; _j < a.length; _j++) {
sumDen = add(sumDen, multiply(a[_j], Complex(Math.cos(-_j * w[i]), Math.sin(-_j * w[i]))));
}
num.push(sumNum);
den.push(sumDen);
}
var h = [];
for (var _i = 0; _i < num.length; _i++) {
h.push(divide(num[_i], den[_i]));
}
return {
h: h,
w: w
};
}
function createBins(n) {
var bins = [];
for (var i = 0; i < n; i++) {
bins.push(i / n * Math.PI);
}
return bins;
}
});