Engineering 103 –UMass Boston

CW 13

(In-Class-Work 13)

(a) Learn the concepts of period (T) and frequency (f) in a cosine or sine waves. The period is the time separation between two consecutive peaks or troughs; the frequency is the number of cycles per second or f=1/T. Using MS Paint:

-Draw a cosine with period 2s, mark T clearly on a plot (manual) in which the t-axis is presented in increments of 0.5s; write on the vertical axis the function as cos(2π*f*t), replacing f by its value.

-Draw a cosine with frequency 0.25 s^-1, mark T clearly on a plots with the same t-axis as above and label the vertical axis as above.

Paste the figures into a Word file. Save it as cw13_lastname.

(b) More on ergonomic VI’s. Modify the VI you created in CW 10 a) and b) and HW 5-8, so it can plot cosine functions of time with any frequency (as input). Modify to include two cosines and also the sum of both. Use your experience with plotting a function, plotting two arrays of data using XY Graph and bundle.

The modified VI should contain in the front panel:

Inputs: values between …, and …; number of points; frequency 1; frequency 2

Outputs: waveform graph 1 (for frequency 1); waveform graph 2 (for frequency 2); waveform graph sum

Use T1=1; T2=0.25; and the smallest number of points to see both curves smooth. Run and paste a copy of front panel and diagram with your name in a text box, into the Word file cw13_lastname. Click here to submit.

*Remember that this is an individual work (turn it in, as instructed, with your name and date). Home-works and class-works count 20% toward the course grade. Class-works are done in class.