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Question about MT Demodulate PSK

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HI, everyone

I am a little confused about the process of demodulation. From the packet link example, we have known that the receiver would chop the samples to many packets, and then demodulate each packet by MT Demodulate PSK.vi, and in the MT Demodulate PSK.vi, each packet would  do many other things such as frequency offset estimate and remove . In my opinion, this process should just do only once estimation in a determined communication process, there is no need do an estimate process for each packet. So the time cost for demodulate a packet will decrease.

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Accepted by HustLiliAn

@HustLiliAn wrote:
In my opinion, this process should just do only once estimation in a determined communication process, there is no need do an estimate process for each packet. So the time cost for demodulate a packet will decrease.

Hello HustLiliAn,

 

That would work for slowly varying channels (controlled lab environments) and devices with high quality integrated circuits (expensive).

 

Take for example your are in a car using your cell phone (you will be the passenger of course). If the car is moving at a certain speed and then stops, your initial channel estimation is no longer valid -- most noteable frequency offset estimation. By estimating the channel characteristics on each packet, the receiver is more robust against interference.

Anthony F.
Staff Software Engineer
National Instruments
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Thanks for your reply!

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