The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> RF Design >> Gain settling requirement for the FM system
https://designers-guide.org/forum/YaBB.pl?num=1407739556

Message started by angel on Aug 10^th, 2014, 11:45pm

Title: Gain settling requirement for the FM system
Post by angel on Aug 10^th, 2014, 11:45pm

Hello

I have one question about VGLNA with AGC in FM receiver front-end design. I made one VGLNA with analog AGC for the PhD research work, if possible, could you please let me know what's the gain settling requirement for the FM system and how fast should this AGC loop achieved?

Thank you very much

Title: Re: Gain settling requirement for the FM system
Post by aaron_do on Aug 11^th, 2014, 6:33pm

Hi,

normally it depends on the communications protocol. For a digital comms system, there is usually some time allocated for AGC settling, PLL locking etc. In your case, there may not be a standard, it may be simply a competition between your design and competitor designs.

All that said, for FM, as I've mentioned before, the amplitude of the signal isn't very important. You can probably design your system with a limiting amplifier at the end. That will make the settling very fast, and the AGC will really just be for optimizing the SNR or power consumption. I suggest reading some papers on FM receiver ICs so you can see what the overall system looks like.

Aaron