What is a Cutoff Frequency?

Sometimes known as a break frequency or corner frequency, a cutoff frequency is a term that is often used in electrical engineering and physics. The term refers to the frequency level at which a device ceases to operate or respond in an efficient manner, effectively causing the device to shut down or cut off. This type of phenomenon is sometimes explained as a reduction of the flow of energy through the device that prevents the consistent function of all the components. When this happens, the device cannot operate at full efficiency, since the necessary power is not present.

When it comes to identifying cutoff frequency in various types of communication channels, the phenomenon may occur in a number of different frequency ranges, both above and below the frequency required to optimize the communication process. With each approach, the frequency is not within the range required to produce the best reception and sending of signals, resulting in transmissions that are weak. A good example of this is a television antenna used to pick up over the air broadcast signals. If the transmissions are at frequencies above or below the optimum range for that antenna, the picture quality will be weak and intermittent, and the sound quality will also be adversely affected. Adjusting the frequency range of the antenna to accommodate a wider bandwidth would help to adjust the situation, resulting in minimizing the range for the cutoff frequency and allowing improved reception to take place.

With some devices, the cutoff frequency is the range at which the device will simply cease to function at all. Once that threshold is passed, the device does not recognize the power flow, since it is too weak to trigger any type of response. The result is that even if there is some energy being received, it is inadequate to activate and operate the device in question. Until the energy flow received is adequate, operation remains impossible.

Standards for various types of transmissions are typically developed in various nations, with many nations choosing to adopt the same frequency ranges for various devices and operations. This helps to create some degree of uniformity in how radio and television signals are broadcast, as well as providing for special frequency bands that can be used by governments and military operations without disrupting frequencies that are in common use for general communication purposes. Combining the right frequency band with a given type of equipment establishes the cutoff frequency above and below that band, making it possible to operate within a given range with relative confidence, even when different types of weather conditions could interfere with the transmission process.