Covering curves - curva.gif (0/1)

[Francisco Priego]

I have a problem, and I´m in a hurry 8( :

I have one time array x0,x1,x2...xn , and one amplitude array
y0,y1,y2...yn that define a pattern curve. I have to get a pair of
covering curves (one lower, and one upper). See the joined .gif to get
an idea, or this ascii chart (use a fixed pitch font to see it
properly):

________________________
| __________________ \ / /
| | ____________ \ \ / / /
| | | \ \ \ / / /
| | | \ \ \ / / /
| | | \ \ \ __/ / /
| | | \ \ _ / /
-A-------- | |
\ _ ---- /
-B----------- | \_________/
-C--------------


B=Pattern curve.

¿any idea to do this?

The time and amplitude array should support any range.

I have done a bad algorith based on add increment of Y at the
X+AX*sin(a),or X-AX*sin(a) (depending if slope is positive or
negative), but it fail with some type of curves and ranges.

(AX and AY is the increment of X and Y, and a is the angle between
one sample and the previous).

|\
| \
A | \
| \
|__/a\
B

a=arctg(A/B)

Please give me any ideas (or VIs) you can have. I have wasted
ten days with this problem, and I can't see a satisfactory solution...
it's exasperting.

A lot of thanks in advance.


Best Regards.

Saludos Fidonet: 2:341/136.53
Paco ¡¡P!! http://www.arrakis.es/~ppriego
ICQ: 2922145

[Craig Graham]

> I have one time array x0,x1,x2...xn , and one
amplitude array
>y0,y1,y2...yn that define a pattern curve. I have to get a
pair of
>covering curves (one lower, and one upper). See the joined
..gif to get

Are the curves pretty arbitrary, in which case a couple of
splines, offset, would work? There's a spline generator at
ftp://ftp.pica.army.mil/pub/labview/vi/lv3.0/spline.llb that
may help if so.

[Francisco Priego]

Hi C.N.Graham@lancaster.ac.uk , hope you are having a nice day

27-May-99 14:36:50, C.N.Graham@lancaster.ac.uk wrote to All
Subject: Re: Covering curves - curva.gif (0/1)

>> I have one time array x0,x1,x2...xn , and one
>> amplitude array >y0,y1,y2...yn that define a pattern curve. I have
>> to get a pair of >covering curves (one lower, and one upper). See
>> the joined .gif to get

C> Are the curves pretty arbitrary, in which case a couple of splines,

They would be noise, DC, ramp,... all sort of signals. I have done a
good implementation yet painting little rectangles surrounding every
point of the curve (in fact I paint only the upper and lower border of
the rectangle from x-AX to x+AX, and I have to discriminate if this new
point ha
s been painted yet from another point).

C> offset, would work? There's a spline generator at
C> ftp://ftp.pica.army.mil/pub/labview/vi/lv3.0/spline.llb that may
C> help if so.

Thanks, but I couldn't load the spline.llb in my LabVIEW 4.0 8-?


Best regards Inet: ppriego@arrakis.es
Paco ¡¡P!! http://www.arrakis.es/~ppriego
ICQ: 2922145

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* Origin: Ve-ni-mos-de-Mar-te.... ¿De marte de quieng? (2:341/136.53)