Hi Marcus,
That makes sense, thanks.
Would you be willing to confirm if what I am doing here is correct?
To first order, the DAC has an SNR of 98dB (16 bit). Then I use Fries' equation to get the NF of the following stages (for the filter and the attenuator, the noise figure is equal to its attenuation). The NF is dominated by the 2nd and third term.
Then I subtract the NF from the SNR which gives me an output SNR somewhere between 92dB and 67dB. Does that sound right?
Gesendet: Montag, 30. November 2020 um 12:48 Uhr
Von: "Marcus D Leech" <[email protected]>
An: "Lukas Haase" <[email protected]>
Cc: [email protected]
Betreff: Re: [USRP-users] UBX160 TX "noise figure"?
Von: "Marcus D Leech" <[email protected]>
An: "Lukas Haase" <[email protected]>
Cc: [email protected]
Betreff: Re: [USRP-users] UBX160 TX "noise figure"?
The output SNR will be utterly dominated by the inherent DAC noise.
There’s a good article here:
https://www.analog.com/media/en/training-seminars/tutorials/MT-001.pdf
Sent from my iPhone
On Nov 30, 2020, at 4:03 AM, Lukas Haase via USRP-users <[email protected]> wrote:
Hello,
Does anyone know what the *TX* noise figure (output SNR) of the UBX160 is?
Roughly?
For simplicity, can neglect phase noise and assume white noise floor.
In words, if I transmit a full-scale sinusoidal signal, what will be the noise floor around that signal?
Of course, this will depend on TX Gain setting.
For example, a -3dBFS signal at TX gain 25 gives -3+25-5.56 = 16.44dBm. What will roughly be the noise power (and hence SNR)?
Thanks,
Lukas
PS: Usually we are interested in receiver (not transmitter) noise but the TX SNR can be relevant for self-interference.
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