Why Cutoff Frequency is a Critical Factor in Filter Designing

July 16, 2019

Signal processing has revolutionized the conventional methods of signal transmission. With the right equipment and technology, systems can now transmit signals over large geographical distances within a short duration.

However, transmission over large distances exposes signals to several disturbances, which include noise, attenuation, distortion, and interference. These disturbances alter the signal’s amplitude and frequency, resulting in the loss of signal integrity. Designers have developed analog and digital filters as a solution to this problem to help restore the corrupted signals.

Designing a filter is a complicated task that requires paying attention to several factors—the cutoff frequency being one of the most essential ones.

While it may sound simple, choosing the cutoff frequency is a critical task that has various considerations and complexities involved.

Before we talk about why cutoff frequency is an important factor for filter design, let’s talk about what a cutoff frequency is and how it affects your circuit performance.

What Is Cutoff Frequency?

A filter operates by allowing a specific range of frequencies to pass through, discarding all other frequencies that lie above or below this range. This particular frequency that defines the filter’s threshold is known as the cutoff frequency.

Since a band-pass filter allows a specific range of frequencies to pass through, it has two cutoff frequencies. Only frequencies that fall in the range of lower and upper cutoff frequencies are allowed to pass through the circuit.

The Importance of Cutoff Frequency

To understand the importance of cutoff frequency better, consider a circuit that’s designed to deal with frequencies that are less than 2 MHz. For this reason, you need a low-pass filter with a cutoff frequency of 2 MHz. So what happens if you choose a filter with a cutoff frequency of 3 MHz?

Your filter will now transmit frequencies up to 3 MHz, and since your useful signal lies in the range of 2 MHz, every other frequency is just random noise that’s damaging your signal integrity.

Now consider choosing a 1 MHz filter for the same circuit. Your filter is now discarding the useful signals that lie above the frequency range of 1 MHz.

In a nutshell; choosing the right cutoff frequency for your filters is a critical factor as it can result in either the addition of noise or signal loss, neither of which is your circuit’s desired response.

If you’re looking for reliable FIR and digital filters, get in touch with ADSANTEC. Our filters are available in a variety of design specifications, so you can choose one that best fits your circuit requirement.

Our range of products also includes delay lines, 4-bit ADC, clock dividers, error detectors, logic gates, and various other components that can help you get started with your next electronic project!

Contact us today for product details and customized design inquiry!