GSM test--AM suppression

am suppression

Can anyone who know how to test this item "AM Suppression" for GSM phone.

Any document describe this measurement method ??

Thanks for your help.

gsm am suppression

About this test you can find in any GSM 05.05 or GSM 11.10 from ETSI
https://www.etsi.org/

am suppression characteristics

Where can I find how to set up test instrument for this test and procedure?
Thanks you.

am supression

The setup is very simple.
An RF Test set (let’s say CMU200) and a Signal Generator (let’s say ESG or SMIQ with framed GSM modulation) are routed through a power splitter to the input of your mobile.
The mobile is in loop-back with RF Test Set (CMU200), receiving a mid-band channel fo (level –99dBm at antenna connector, that is 3dB above reference sensitivity).
The frequency of the Signal Generator is set to any frequency fg = fo > 6MHz, but shall be inside of the receive band, and shall be an integer of channel spacing (200kHz). The level of the Signal Generator at antenna connector shall be as in the spec table (beware to take into account the splitter loss).
Is specifying that you can use a notch filter (notch frequency = fo, between Signal Generator and splitter) to minimize the co-channel interferer that can affect your test. You have to take into account the notch attenuation at Signal Generator frequency (fg).

am suppression test

Vfone,
Two questions need your help
1. AM suppression interference should be modulated or CW blocker ? In phone level(Call mode), ususally modulated blocker with 61-86bits offset is being test while CW signal being test in Evaluation board level(Test mode). It supposed that CW induce DC noise presentating @ IQ while AM modulated blocker induced Random noise. Will those two noise type get very close approximation connecting call mode with test mode tesing? I heard from RFIC company said, yes they are almost equal in terms of testing view.

2. AM suppression testing frequency is 6MHz offset from desired channel frequency.
How was that 6MHz being made in ETSI spec ? simulation or just a initial test frequency long long time ago ??And how to deside AM blocker level in ETSI?

Thanks with Regards,
wilson

gsm am suppression test

GSM AM suppression test do not use CW blocker. The interferer signal is GMSK modulated, one burst active, synchronized and delayed as in the spec.
I don’t know why ETSI chose the 6MHz spacing, but AM suppression test is not only a GSM spec, is made for different networks also.