DOCSIS 3.0 Set-Top-Box Tuner Architecture

A Dual Tuner DOCSIS 3.0 set-top-box

Recreate the RF Local Oscillator architecture of the tuner using black-box testing.

• The modem was taken apart and tuner IC identified
• A 256-QAM modulator plus an RF upconverter was used as input signal source
• The RF input signal was split and converted into two balanced signals prior to the two tuner IC inputs.
• A magnetic loop probe was connected to a spectrum analyzer for signal reception
• The tuner was put through various carefully designed test cases and input and output combinations and responses were observed.

Successful verification of the overall architecture of the dual tuner, including all the oscillator frequency settings for various channels.