Filtering out unwanted signals (urgently please )

[TBH95]

We are using two USRP 2920 and two SMA-703 antenna with the following parameters and VI . Our receiver receives random signal from the nearby area while the Transmitter is off and we want to filter them out so the receiver receives only the transmitted signals.   

[wiebe@CARYA]

The receiver and transmitter settings are mostly irrelevant. I hope it's allowed to use that frequency...

We need to see the signal that is desired, and the signal that is unwanted. And with seeing I mean we need that data!

There is a change it's not possible to filter out the unwanted signal. The easies way to filter would be to use a low pass, high pass or band pass filter, but that's only possible if the frequencies don't overlap.

[TBH95]

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wiebe@CARYA wrote:

The receiver and transmitter settings are mostly irrelevant. I hope it's allowed to use that frequency...

We need to see the signal that is desired, and the signal that is unwanted. And with seeing I mean we need that data!

There is a change it's not possible to filter out the unwanted signal. The easies way to filter would be to use a low pass, high pass or band pass filter, but that's only possible if the frequencies don't overlap.

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The carries frequency of both transmitter and receiver is 1.2 GHz and the and waveform size is 10000 while number of samples is 20000.

I have already tried a band pass filter but it is not working.(according to the attached settings what should be the High and low cutoff frequencies for the filter ).

These pic shows unwanted signals only because the transmitter is off.

[wiebe@CARYA]

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@TBH95 wrote:

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wiebe@CARYA wrote:

The receiver and transmitter settings are mostly irrelevant. I hope it's allowed to use that frequency...

We need to see the signal that is desired, and the signal that is unwanted. And with seeing I mean we need that data!

There is a change it's not possible to filter out the unwanted signal. The easies way to filter would be to use a low pass, high pass or band pass filter, but that's only possible if the frequencies don't overlap.

---

The carries frequency of both transmitter and receiver is 1.2 GHz and the and waveform size is 10000 while number of samples is 20000.

I have already tried a band pass filter but it is not working.(according to the attached settings what should be the High and low cutoff frequencies for the filter ).

These pic shows unwanted signals only because the transmitter is off.

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The images (haven't opened the VI's) have a carrier frequency of 400M, and a bandwidth of 200k. I don't see how that would result in 1.2GHz...

Is the transmitter completely off, or is it not transmitting a signal? There's a subtle difference. IIRC, when I used an USRP to transmit a signal, I had to use the a frequency offset to prevent it from transmitting noise at the carrier frequency. I thing it was called LO Frequency, I'm not sure. I don't know if the same applies to the receiver, haven't been receiving a lot (just transmitting).

It would be interesting if this "interference" is in fact a measuring artifact, or a signal. What happens if you change the carrier frequency? Does the interference shift?

Without both the desired signal and the noise signal, there is no way to say how the noise can be filtered.  And there might not be a way to do it...

[JÞB]

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@TBH95 wrote:

We are using two USRP 2920 and two SMA-703 antenna with the following parameters and VI . Our receiver receives random signal from the nearby area while the Transmitter is off and we want to filter them out so the receiver receives only the transmitted signals.   

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The receiver is going to receive whatever is around.  That is sort of the point of a receiver.

What you may wish to do instead is to conduct the signal through an attenuator and do not involve the antennae at all.