"over a time" is a perfectly acceptable phrase in written English.
You can use it to refer to a specific period of time, as in this example: "We have observed an increase in sales over a time of four months."
Isn't Alphasyn useful for measuring accumulated stimulation over a time period?
Fairness is usually ensured over a time window of several network propagation delays.
System performance measures for systems observed over a time interval of random duration are introduced.
Heureaux presided over a time of unprecedented stability and national growth.
Typical errors in the total energy over a time period of 10τ remain below a percent.
In dynamic continuous systems, such a value is observed over a time interval.
Capacitance drifts are observed over a time scale of a few hours at room temperature.
Before Nadal can serve, he's given a warning over a time violation.
Tumor size was measured over a time period of 19 d using a caliper.
Autophagy displays a waveshape over a time course of serum starvation12.
The data were acquired during slow warming over a time of several hours.
