Reply to post: Re: Wavelength in kHz?

Halfords invents radio signals that don't travel at the speed of light


Re: Wavelength in kHz?

"What's the modulation method got to do with the frequency used?"

Quite a lot - I worked (until very recently) with systems that carried multiple wavelengths on a single fibre bearer - 10 years ago I was working with 10Gb/s systems using 100GhZ spacing of the carrier frequencies (Mach-Zender modulators, simple on/off keying of the carrier) - when I retired 3 weeks ago, I was working with DPQPSK (Dual Polarization Phase Shift Keying) systems that will do up to 520Gb/s at 50GHz spacing of the carrier frequencies - and the distance between regenerators (as opposed to amplifiers) has gone from 100s of Kms to 1000s of Km.

The money now days is in developing better modulation and error correction protocols - demanding more bandwidth for higher bitrates very much labels you as an 'also ran'.

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