BUC vs LNB: Understanding the Differences

This page compares BUC vs LNB and mentions the difference between BUC and LNB.

BUC is the short form of Block Up Converter, and LNB is the short form of Low Noise Block Converter. Both of these devices, BUC and LNB, are used in VSAT transmission systems for relaying voice/data via satellite to a larger portion of the earth.

BUC - Block Up Converter

As mentioned, BUC stands for Block Up Converter. As shown in the figure, it consists of two modules in one package:

• RF Up converter
• RF Power Amplifier

Following are the functions of BUC:

• Frequency conversion: It converts a lower frequency to a higher frequency. This process is referred to as RF up conversion, and the module is referred to as an RF up converter.
• Amplification: It boosts the amplitude level of the RF signal converted in the previous module. This process is referred to as RF amplification, and the module is referred to as an RF Amplifier.

The advantages of using a BUC in place of two separate modules (up converter and amplifier) are lower cost and easy installation. The BUC is placed between the satellite modem (i.e., modulator output) and the antenna. Refer to BUC Vendors.

LNB - Low Noise Block Converter

As mentioned, LNB stands for Low Noise Block Converter. As shown in the figure, it consists of two modules in one package:

• RF LNA (Low Noise Amplifier)
• RF Down converter

Following are the functions of LNB:

• Low Noise Amplification: It boosts the amplitude level of the received RF signal while maintaining CNR (Carrier to Noise Ratio) in order to avoid any distortion.
• Frequency conversion: It converts a higher frequency to a lower frequency. This process is referred to as RF down conversion, and the module is referred to as an RF Down converter.

The advantages of using an LNB in place of two separate modules (LNA and down converter) are lower cost and easy installation. The LNB is placed between the satellite modem (i.e., demodulator input) and the antenna. Refer to LNB Vendors.