VSG60 AWGN generation

[Ewald]

Hi
We need to generate AWGN for interference simulation and are unsure if the VSG25 would comply or should should rather purchase a VSG60.
Please advice.

Requirements for the AWGN signals are as follows:
(Please also see attached PDF)
Frequency(MHz) Adjacent power (dBm)
1,524 -65
1,548 -95
1,554 -105
1,615 -105
1,627 -85
> Pass-band bandwidth: >= 1 MHz
> Ripple in pass-band: < 3 dB
> Stop-band attenuation: >= 62 dB
> Transition band between passband and stopband: 4 MHz
> Within the transition band the filter shall not exceed the maximum passband gain.

Thanks

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[Andrew]

Hello Ewald,

I believe the VSG60 would be able to meet the AWGN requirement, but not the 2FSK requirement (at least with the included software). The minimum symbol rate for 2FSK will be 4kS/s on the VSG60. If you need to go lower, you would need to create your FSK waveform as an oversampled arb file and load it as an arb waveform.

You could use the VSG25, but you would need to use a multi-tone signal to simulate AWGN or create your own arb waveform for AWGN. The VSG25 also has no reconstruction filter on the DAC which will create images that might interfere in adjacent bands. Similar restrictions on the FSK signal for the VSG25 as well, except the VSG25 has only a 2k waveform size limitation, whereas the VSG60 does not. Since you will need to oversample the waveform the full waveform won’t fit in the VSG25 arb memory buffer.

The VSG60 software generates AWGN. In some configurations you might see a spurious signal. The picture below at 1524M shows an example spur as well as the adjacent channel performance of 1MHz AWGN channel. I also include a screenshot of the VSG60 software for this configuration.

Let me know if you have additional questions.

Regards,
Andrew

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