a shm oscillator has peroid of
Depending on the system executing Harmonic Motion the equation of motion will be defined and from that only you can get the corresponding equation of frequency and the time period is given by T=2*pi/Frequency.
Now for a simple pendulum its T=2*pi*(l/g)^1/2
You can consider any standard books in order to learn about all this details.
I hope this answer helps. All the very best for your future endeavors!





