ACLR Tests

Hello

Is there a video or a write up that describes setting up an adjacent channel leakage ratio test using an SM200C with this new VSG200 signal source?

We would use some help and it’s always nice to have some specific documentation.

Thanks

jom

[Justin Crooks]

Jom,

There is a YouTube video about channel power / adjacent channel power: https://www.youtube.com/watch?v=arUiwxBpMTE
Also
https://www.youtube.com/shorts/7GpbTg3xyvk
and a guide here:
https://signalhound.com/wp-content/uploads/2018/01/Occupied-Bandwidth-and-Channel-Power-Measurements-with-a-Real-time-Spectrum-Analyzer.pdf
but nothing specific to the VSG200 / SM200.

• This reply was modified 3 weeks, 1 day ago by Justin Crooks.

Is there a way to measure EVM (Error Vector Magnitude) directly?

jom

Thanks for calling in today. It was nice talking with you. If you have follow up questions, please email support@signalhound.com or give us a call again.

Andrew

Hello

Another question on Dig Demod. I was using the OFDM modulation from the VSG200 but Spike didn’t seem to have a reciprocal Dig Demod choice from the pull down menu (such as the one for QPSK). Is this a licensing issue because it doesn’t warn you on that?

I was just doing a simple out from the VSG to the input of our SM200. We’ll be measuring an amplifier soon for EVM soon….

Thanks

jom

We do not have a generic OFDM demodulation mode in Spike. A common workaround would be to transmit an 802.11a signal with the VSG60 and then demodulate that with the WLAN demod mode in Spike. No licenses required, and it will simulate a 20MHz BW OFDM signal for your amplifier test.

Do you think this would be sufficient?

It might work for us. LTE might be better though…not sure yet. I’ll have to get this Matlab runtime thing going though….

As to your statement about the VSG60 I assume you meant VSG200 which is what we have.

jom

The software supports both the VSG60 and VSG200, so either device will work for this type of test.

A couple of questions about LTE:
1) I place the VSG200 output directly to the SA and I get a 5% EVM. Shouldn’t it be below 1%? There is not DUT involved.

2) Is there a way to get ACPR whil running LTE?

3) I went into the Spectral Mask mode and it seemed to fit rather well with the LTE I was using (20 MHz). Are there other “build in” SEMs? Or you do you have to build them yourself…just curious.

Thanks

jom

1) It depends on your setup. Since you mentioned using LTE, there isn’t a real LTE EVM measurement like there is for WLAN or a standard signal carrier modulated signal. LTE does a quick EVM analysis on the MIB and PSS, but these are subcarriers in a very narrow band, and not representative of the full signal bandwidth EVM.

If you wanted to provide a picture of your setup and help making a good EVM measurement, I would recommend reaching out to support@signalhound.com.

2) Not while running LTE. Only in sweep mode. You would have to go back and forth between measurements.

3) There are a number of built in masks, (lower right hand corner in the control panel), but we don’t include any LTE masks. You would have to build your own.

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