Cisco Cisco 1 GHz GainMaker Amplifier Références techniques
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GainMaker System Amplifiers Using Automatic Gain Control (AGC)
Technical Bulletin
Overview
Audience
This technical bulletin applies to Cisco
®
customers using GainMaker™ System
Amplifiers with Automatic Gain Control (AGC).
The Situation
A Cisco customer recently noticed an unusual picture distortion when using
GainMaker amplifiers equipped with AGC. This effect appears as an approximately
½-inch wide faint white vertical bar that typically travels slowly from left to right
across the television screen. Subsequent investigation of this phenomenon at Cisco
has determined that this vertical bar is being generated in the GainMaker AGC
detector module. The effect appears to be a form of concentrated cross modulation,
one that is within the tested and specified parameter limits for standard amplifier
cross modulation yet remains visible to the eye under certain conditions. We are
referring to this distortion as AGC-induced cross modulation (AGC XMOD).
Important Note
Because the GainMaker AGC design is unique, this distortion does not exist in any
other Cisco RF products.