Fundamental Overload – All You Need To Know

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Attaining overload performance and a decent signal while maintaining sensitivity is one major challenge of the radio receiver design. As the radio requires sensitivity to receive weak signals, overload performance is crucial. At the same time, it should manage strong signals sans overloading.

As we increment the utilization of Bluetooth devices, Wi-Fi, cell phones, NFC along with conventional radio frameworks, it is mandatory for all of them to work in other’s presence.

This is in close vicinity and transmits signals on adjoining frequencies. As a result, overload and good signal handling are essential.

What is Fundamental Overload?

Fundamental overload is essentially a sort of interference in a receiver that is a coordinate result of exceptionally solid signals. Strong RF signals lead to inducing currents on receiver components, overloading them, and making it non-viable to aptly process weaker signals.

In simple words, you can understand it as a condition when super strong signals overwhelm a receiver’s ability to reject them.

What Causes Fundamental Overload?

There are various causes of fundamental overload. Let’s take a look at them.

Receiver Blocking

You might experience receiver blocking when there are strong RF emissions from unwanted sources intruded on communication channels. This results in reduced performance in the receiver circuitry, which further leads to a reduction in sensitivity.

Intermodulation Performance

The two basic parameters for receiver performance include intermodulation performance and distortion. Unwanted signals can rise due to the existence of intermodulation products that can cover the required signal.

Intercept Point

It is responsible for increasing the capacity of strong signal handling of an amplifier, receiver, or mixer. Intercept point is the graph level where level lines obstruct i.e., where the level of third-order intermodulation products is equal to the required products.

Cross Modulation

It is an effect that you can notice in radio receivers when the amplitude-modulated elements of a strong signal emerge on other received signals.

How to Improve Overload Performance?

In order to improvise the handling performance of signal and radio overload, radio receivers possess several ways to reduce signal levels.

Make Use of High-Level Radio Frequency Amplifier

For guaranteeing the finest radio over-burden execution, make sure that the primary RF amplifier is able to handle signals of a high level while remaining linear.

High-Level Mixer

It is essential to own a high intercept of third-order for ensuring that the mixer does not gets overloaded due to strong signals. Make sure that it possesses a high input level of the local oscillator.

Automatic Gain Control

A circuit designed to maintain constant output signal level post-amplification, an AGC provides more amplification to weak signals and less amplification to strong signals.

Although this works for most of the situations, it might not be capable of preventing the initial stages of radio receiver from overloading. This is especially true when signals are received off-channel. This happens because AGC will remain unaffected by these signals, but they will anyway present themselves to initial stages of the receiver before being filtered.

RF Attenuator

Several radio receivers might make use of an RF attenuator. This is helpful to diminish the RF input when there are strong signal levels.

Final Thoughts

Our lives have filled with technology. As a result, the likelihood of interference has augmented. Fundamental overload is frequent with your transceiver when another operator is transmitting close to your station on the same band to which your radio is tuned. To prevent the same, it is essential to keep the above-mentioned points in mind and take necessary action.


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