The phrase "a variable frequency" is correct and usable in written English.
It can be used in contexts related to physics, engineering, or technology, particularly when discussing systems that operate at different frequencies.
Example: "The device is designed to operate at a variable frequency, allowing it to adapt to different signal conditions."
Alternatives: "an adjustable frequency" or "a fluctuating frequency".
It first applies "an AC voltage with a variable frequency to at least one electric conductor," Mr. Marksteiner writes.
A variable frequency controller drives each pump.
Buffin, A., Mailleux, A.-C., Detrain, C. & Deneubourg, J. L. Trophallaxis in Lasius niger: a variable frequency and constant duration for three food types.
In such a drive, a variable frequency and voltage supply from an electronic converter may be provided for starting.
D.J. Perreault, K.K. Afridi and S.J. Gunter, "Systems and Methods for a Variable Frequency Multiplier Power Converter," U.S. Patent 9,819,272, November 14 , 2017
D.J. Perreault, K.K. Afridi and S.J. Gunter, "Systems and Methods for a Variable Frequency Multiplier," U.S. Patent 9,853,550, December 26 , 2017
Theoretical guidance for adjusting the ventilation branch quantity for a variable-frequency mine ventilator was provided.
The main application for permanent-magnet motors is in variable-speed drives where the stator is supplied from a variable-frequency, variable-voltage, electronically controlled source.
By replacing old escalators with new ones that use a variable-frequency drive and numerous sensors, positioned near the escalators, officials hope to save on energy costs, and, just as important, reduce the wear and tear on the many mechanical parts in the heavily used machines.
In the rf measurements, the sinusoidal drive signal is generated by a variable-frequency microwave source and guided to the sample through low-loss coaxial cables, which are attenuated at different temperature stages of the cryostat as shown in Supplementary Fig. 1c.
We have shown that duct modeling using the generalized RBF neural network (DM_RBF), which has the capability of modeling the nonlinear behavior, can suppress a variable-frequency narrow band noise of a duct more efficiently than an FX-LMS algorithm.
