Re: [Discuss-gnuradio] (no subject)

[Marcus Müller]

Hi Vishwanatha,

Demodulation of phase-depending modulations requires some kind of synchronization.

There's more approaches than costas loops to phase synchronization; however, they're usually very specific to a channel/signal model and can't be universally applied, or very inefficient, or very complicated to explain. So the important question here is: Why do you need something else than a phase error feedback loop? You can of course just estimate your phase offset once using a set of known symbols (e.g. a preamble), and use that for as long as you think your channel and transceiver are coherent, but I think you've already considered that, since you ask how to get rid of the loop, and recognized that it's a good idea to continuously account for changing phase.

Greetings,
Marcus

PS: There's not only sirs on this list, also ladies, and we're not very formal on here, so a quick "hello" would totally be sufficient :)

On 03/12/2015 07:35 AM, Vishwanatha H G wrote:

sir, can we achieve 16 qam demodulation constellation without using costas loop? if possible please send me the flow graph. thank you

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