Cisco Cable TV EGC GaN Segmentable Node A90201, RF Amplifier Teardown

[Mads Barnkob]

Teardown of Cisco Cable TV EGC GAN node and drop amplifier. Electronic Gain Control (EGC) technology and GaN (Gallium Nitride) monolithic microwave integrated circuits (MMICs}.

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RF output level adjustable over a wide range: 94 to 119 dBµV
Wide optical input: -7 to +2 dBm, 1200-1600 nm wavelength.
Configurable for 1 GHz or 862 MHz operation
Configured by Electronic Gain Control (EGC) technology
Full segmentable in forward path and reverse path
Automatic redundancy switching for forward path

From the backbone network connected fiber TX module, the signal goes through a pSEMI PE4256 SPDT switch. Before the pre-amplifier, a Peregrine Semiconductor (pSemi) PE4304 75Ω RF digital attenuator, 6-bit, 32.5dB, DC-2GHz. The pre-amplifier is a Skyworks ACA2402, 750-1000 MHz 22 dB gain push-pull line amplifier. The output amplifier is a RFMD RFCM2680, 45-1003 MHz, power double amplifier. 450 mA at 24VDC, for a 22.5 dB gain. From here the copper cable network to the end-user, is connected.

[Da_Stier]

I came across a whole crate of these exact boards on the scrapyard, some time ago. I guess now I know where they came from.
The combination of the old TV network stuff going only in one direction and the fibre seems pretty interesting, I wonder how much of it was an afterthought that just got "bodged on top" and how much was actually meant to be added at some point.

These cases are pretty cool, I think they make great project boxes, maybe even for stuff that gets mounted outside or on a antenna tower or something similar.

As always thanks for the look. 



Greetings,
Michael