Looking on the internet deeply has found these results:

period of time is the most popular phrase on the web.

time period 162,200,000 results on the web	period of time 1325,000,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
The other Contracting Party shall then take appropriate corrective action within an agreed time period. The modalities of the expulsion should allow the situation to be rectified within a reasonable time period. The parties are willing to freeze their daily frequencies for a limited time period. The time period for which this coverage is representative. Any amount not committed within a certain time period should be paid back. Such time period shall be a maximum of three months. If necessary, the Commission may request additional information to be submitted within a reasonable time period specified. This common approach should be established for a limited time period.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

time period

162,200,000 results on the web

period of time

1325,000,000 results on the web

More popular!

The other Contracting Party shall then take appropriate corrective action within an agreed time period.
The modalities of the expulsion should allow the situation to be rectified within a reasonable time period.
The parties are willing to freeze their daily frequencies for a limited time period.
The time period for which this coverage is representative.
Any amount not committed within a certain time period should be paid back.
Such time period shall be a maximum of three months.
If necessary, the Commission may request additional information to be submitted within a reasonable time period specified.
This common approach should be established for a limited time period.

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.