In high speed data communications, the industry has evolved and implemented complex modulation schemes which vary a signals voltage (amplitude), phase, and frequency in order to transmit more data, faster. The following will cover these methods in order to describe how Quadrature Amplitude Modulation (QAM) works in DOCSIS communications. We live in an analog world. Sure, [...]
Most of us are quite comfortable with changing the dial on our FM radios. Don't like what's on Soft 95.1 FM, then change the frequency (Kenneth) to 102.5 FM for some classic rock. What you have actually done is changed the RF (radio frequency) tuner in your car stereo from a lower frequency of 95.1 MHz to a higher frequency of 102.5 MHz where there was a different station playing. The fact that two different stations were playing...
Over the past several years of training people on troubleshooting DOCSIS® networks and explaining how DOCSIS cable modems and CMTSs work, I have been asked numerous times - "Why don't you write a book on this?" You see, there is no definitive book, guide or manual that explains the Data-over-Cable Service Interface Specification (DOCSIS) other than the several hundred page specification...
