Reputation
Top tag
Next privilege 100 Rep.
Edit community wikis
Badges
1 8
Newest
 Enthusiast
Impact
~2k people reached

  • 0 posts edited
  • 0 helpful flags
  • 5 votes cast
May
22
awarded  Enthusiast
May
6
comment Chirp with linearly changing frequency and amplitude?
Could you use this "linear amplitude & frequency chirp" function to do a regression to estimate the instantaneous frequency of a smooth curve in real time (online analysis)?
May
6
accepted Chirp with linearly changing frequency and amplitude?
May
6
comment Chirp with linearly changing frequency and amplitude?
I don't think so. Ideally I would also define an A0 and A1: the starting and ending amplitude, so the amplitude "line" goes from (1,A0) to (T,A1), so the equation of this line would be: y-A0=(A1-A0)/(T-1)(x-1). Thinking of the standard equation of a sinusoid, which is Asin*(2pif*t+theta0), in that case you first multiply with the amplitude. So instead of a constant, it would be the equation of the amplitude line?
May
6
asked Chirp with linearly changing frequency and amplitude?
May
4
accepted Convert quadratic bezier curve to parabola
Apr
30
revised Convert quadratic bezier curve to parabola
added 274 characters in body
Apr
30
revised Convert quadratic bezier curve to parabola
added 210 characters in body
Apr
29
revised Convert quadratic bezier curve to parabola
added 6 characters in body
Apr
29
answered Convert quadratic bezier curve to parabola
Apr
29
revised Convert quadratic bezier curve to parabola
added 31 characters in body
Apr
29
revised Convert quadratic bezier curve to parabola
added 89 characters in body
Apr
29
revised Convert quadratic bezier curve to parabola
added a link
Apr
29
comment Convert quadratic bezier curve to parabola
The control points are known, so logically the red Bézier curve is known also. The coordinate system is a Cartesian grid, with constant increments of 1 on both Y & X axes. The solution has to be related to the fact that the line through P0 & P1 is tangent to the Bézier curve in P0 and P1P2 tangent to the curve in P2. So the slope of the tangent to the parabola = the slope of these 2 lines. And the point where these 2 lines cross is P1. And to get c I think you need to plug in the x values of P0 and P1 into the ax^2+bx+c equation to get their y-value after you know a & b. I think..
Apr
29
asked Convert quadratic bezier curve to parabola
Apr
7
accepted Bezier extrapolation
Apr
3
comment Bezier extrapolation
So I guess I am looking for the ab-normal way to do this. It really should not require an iterative process. Could you suggest another spline with similar properties that would not have this problem?
Apr
3
comment Bezier extrapolation
Thanks fang, I did that, but my goal is exactly not to have to decide the t-value of the last data point: it should be part of the regression: the fit of the Bézier curve through the last few data points will be better/worse, depending on how far to the right I place the last control point. There is only 1 solution that automatically finds the best way through all points while respecting the restrictions that does not have t ouse any assumptions or manual settings (like the t-value at the last data point).
Apr
1
revised Bezier extrapolation
added 117 characters in body
Apr
1
asked Bezier extrapolation