CATV Amplifier Design Based on DOCSIS 4.0 Products

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CATV Amplifier Design Based on DOCSIS 4.0 Products [Copy link]

DOCSIS 3.1 的出现让 CATV 提供商能够增加上下行容量。新一代 DOCSIS 4.0 产品目前正处于设计阶段。使用正确的 CATV 放大器可显著提高解决方案的效率。

To stay competitive in the evolving cable television (CATV) business, innovative technologies are needed to meet user demands. CATV amplifiers based on gallium nitride (GaN) technology play an important role in this evolution.

Gallium nitride (GaN) devices can provide more than necessary efficiency and performance to meet DOCSIS requirements for CATV amplifiers. In HFC networks, consistent linearity is the primary requirement for reliable data transmission and signal integrity. Nonlinear behavior of active power devices can degrade signal quality, causing bit errors in digital channels and sometimes outright failures when trying to demodulate the signal.

The linearity of a gain block or amplifier depends primarily on the following factors:

Semiconductor Technology

Circuit Design

Power consumption

Cooling by design

When designing HFC amplifiers, it is critical to maintain high linearity and efficiency, and GaN-based components offer clear advantages in this regard. Figure 2 shows the basic components of a CATV amplifier. In terms of linear output, the downstream performance of an HFC amplifier or node depends heavily on the output stage gain block (also known as a “power doubler”).

Figure 2. CATV amplifier block diagram.

GaN 代表功率放大器设计的一项支持技术，能够满足 DOCSIS 3.1 和 DOCSIS 4.0 标准的要求。图 3 展示了最初使用 GaAs 场效应晶体管 (FET) 实现增益单元架构的设计阶段。使用基于 GaN 的元件代替 FET3 和 FET4 可显著提高性能，因为这些器件具有高频运行、高电压耐用性、高电流密度和功率处理等特性。与 GaAs 的 1 W/mm 相比，GaN 最高支持 10 W/mm。

Figure 3. Improving gain cell architecture by using GaN-based FETs.

Figure 4 shows the advantages of GaN technology by comparing the relative properties of material technologies used in cable TV gain cell architectures, which allows MSOs to maintain existing amplifier spacing while increasing linear output. This can greatly reduce upgrade costs and enable fiber depth solutions, placing fiber closer to customers while reducing or eliminating amplifiers to provide better service.

Figure 4. GaN-based component characteristics compared to other solutions.

Building a CATV solution that adapts to future development. Today's gigabit connections are very fast, but it is said that the new generation of DOCSIS 4.0 products will increase download speeds by 10 times or upload speeds by 5 times, so the design of CATV amplifiers based on gallium nitride (GaN) technology that supports this standard is even more important. Friends who want to know more detailed design solutions can click to read the original article .