Re: [Discuss-gnuradio] Measure and record the phase at the receiver

[Marcus Müller]

Aside from that, sorry, Marcus L is right: phase is the "angle of the complex sample you're receiving *relatively to how it was sent*".

On 03/23/2017 06:02 PM, Marcus Müller wrote:

Hi Fernando,

What if I told you I can predict the relative phase to be uniformly distributed across (0,2π( , if you don't synchronize?

Anyway, phase is just the angle of the complex sample you're receiving, so: use the complex_to_arg block!

Best regards,
Marcus

On 03/23/2017 05:53 PM, Trejo Treviño, Fernando Alberto 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

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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 receiver

 

Hi Fernando!

On 03/22/2017 06:51 PM, Trejo Treviño, Fernando Alberto wrote:

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.

Cool :)

I would like to add a phase shift at the transmitter side via the use of a multiplier block with an exponential.

Ah, so a multiply_const with a constant of $e^{j\frac{2\pi}{f_\text{sample}\varphi}$, yeah.

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.

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).

Best regards,
Marcus

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