Phase is a relative measurement. Against what are you measuring the incoming phase?
You can measure a PSK signal instantaneous phase-shift by computing the arctran2 between adjacent critically-sampled samples. But there's no way to look at a signal and say "what is its absolute phase" without having something against which to measure said phase.
On 2017-03-23 12:53, Trejo Treviño wrote:
I am aware that a random phase shift will be introduced by the channel, but I need a method to measure the received phase (even if it does not exactly match the one from the transmitter) and store it, so I can then run some statistics on them
This is why I think that the TX and RX do not need to be phase-synchronized.
Best,
Fernando Trejo
From: Discuss-gnuradio <address@hidden> on behalf of Marcus Müller <address@hidden>
Sent: Wednesday, March 22, 2017 7:02:35 PM
To: address@hidden
Subject: Re: [Discuss-gnuradio] Measure and record the phase at the receiverHi Fernando!
On 03/22/2017 06:51 PM, Trejo Treviño, Fernando Alberto wrote:Cool :)Hi Marcus!
I am implementing a transmitter and a receiver model using two USRP N210s. Both are using GFSK modulation, and the data is transmitted at 2.4 GHz.
Ah, so a multiply_const with a constant of $e^{j\frac{2\pi}{f_\text{sample}\varphi}$, yeah.I would like to add a phase shift at the transmitter side via the use of a multiplier block with an exponential.
Well, you can't see absolute phase without further ado – that would need your TX and RX to be phase-synchronized (you don't know the electrical length between your transmitter and receiver, it's absolutely random by itself).Then, at the receiver I would like to receive this transmitted signal and check if the phase matches the one that was transmitted. This is why I need a measuring method.
Best regards,
Marcus
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