translation into sine wave
translation into sine wave
(OP)
I have a reciprocating test table connected to a DAQ that outputs position sampled at the rate of 20 samples per second.
The positional output is a range of values from 0 to 20 and over time a sample of 10 cycles is normal.
I would like to graph this set of data in the form of a sine wave; 0 and 20 correspond to the points where the graphed line crosses the x axis and the peak of the sine wave is at 10 and -10.
I'm struggling and need some help. Can anyone suggest a formula for translating this data?
The positional output is a range of values from 0 to 20 and over time a sample of 10 cycles is normal.
I would like to graph this set of data in the form of a sine wave; 0 and 20 correspond to the points where the graphed line crosses the x axis and the peak of the sine wave is at 10 and -10.
I'm struggling and need some help. Can anyone suggest a formula for translating this data?





RE: translation into sine wave
You can only graph something as a sine wave if it is a sine wave.
Otherwise the graph will look like whatever it is.
RE: translation into sine wave
What are you trying to do ?
If you have data of amplitude vs. time, why not simply plot it ? If it looks like a sine wave it probably is but you can test this by also plotting a sine wave alongside it.
You say "The positional output is a range of values from 0 to 20 and over time a sample of 10 cycles is normal." (sic)
But elsewhere you say the range is from -10 to +10. Which is it ?
good luck
RE: translation into sine wave
RE: translation into sine wave
The output through the DAQ is simply a set of numbers ranging from 0 to 20 (position of the table in inches). As the table cycles, the numbers increase from 0 to 20 and then decrease from 20 to 0 and repeats.
I'm not looking for an exact sine wave. I just need a sine wave shape (which this data does produce). However, I need the shape to be shifted so that the 0 and 20 values correspond to 0 (crosses the x axis).
The area of interest is when the table is moving. There is no significant occurence at 0 or 20.
I guess what I really need is the plot of velocity.
Thanks anyway.
RE: translation into sine wave
Velocity is the first derrivative of position.
RE: translation into sine wave
derivative is delta_pos/delta_time
TTFN
FAQ731-376: Eng-Tips.com Forum Policies