EN300220 and phase noise

I would say that you should keep your phase-noise below the level where your radiated power is less than -36 dBm when integrated from two channels away and out. On both sides.

"upda" a écrit dans le message de news: 44abc250$0$17940$ snipped-for-privacy@authen.yellow.readfreenews.net...

Thanks Daniel, that's effectively a potential interpretation. However I must admit, well, that the result in terms of phase noise is quite hard to comply with at least with low cost transmitters... and I was hoping to get another answer ;+)

Hello Robert,

I don't know your transmitter but if noise from the PLL is a concern experiment with the loop bandwidth. If it needs to remain agile you might consider two loops, one to do the fast pull-in and the slower one to keep the lock.

"Joerg" a écrit dans le message de news: W_Sqg.60213$ snipped-for-privacy@newssvr12.news.prodigy.com...

Thanks Joerg. Have you the same understanding of the standard than Daniel for such a narrow band transmitter I mean :

P(Fc-CBW/2 to Fc+CBW/2) < whatever si the nominal autorized in-channel power P(Fc+CBW/2 to Fc+3CBW/2) < -20dBm (adjacent channel) P(Fc+3CBW/2 to Fc+3CBW/2+100KHz) < -36dBm (application of the "spurious" spec starting just after the adjacent channel)

(with CBW=channel bandwidth and F0 the center frenquency)

Hello Robert,

I am not familiar with that part but AFAIR we had to design to 4nW spurious and 250nW adjacent. However, that was under 1GHz. This would be more than what you have listed.

Wish I had it in French or at least in English but if you can plow your way through some German this might help:

Best would be a brief chat with your EMC lab about what limits they test for (or have to test for).

So Robert, what type of oscillator do you have? PLL? Is it some all-in-one radio IC? Just an external coil?

"upda" a écrit dans le message de news: 44acb15b$0$17976$ snipped-for-privacy@authen.yellow.readfreenews.net...

PLL/VCO/modulator chip with external coil, but trying to use in for a non standard application. I know how to optimize its phase noise (or at least how to balance it with loop filter, etc), but my question is really to understand what's the standard is specifying. I'm in touch with a notified body to try to have a definitive answer...

Thanks for your help, R.

Hello Robert,

Way to go. A standard is one thing. But at the end of the day the guys in the certified lab decide how they'll measure compliance. Been there a lot, and there is absolutely no argueing with them if you think that one test or the other is a bit too strict versus the standard.

Seems you have the loop filter licked. If it's FM then the other thing to look out for is the modulator input. You might have to muffle the higher spectra a bit, especially if it is a data stream.

I am pretty sure this won't happen with your experience but in case others are following the thread: When called out to find a "cure" for a failed compliance test the number one problem I found with transmitters was their power supply. Mostly there were remnant switcher spikes, RAM banking transients, video sync and all kind of other stuff riding along. This resulted in almost perfect AM modulation right onto the carrier. You could see a picket fence on the analyzer. It doesn't take a lot to blow through -20dbm or -30dBm.

"Joerg" a écrit dans le message de news: 1acrg.62357$ snipped-for-privacy@newssvr27.news.prodigy.net...

Yes Joerg, you're fully right. In fact I got today a prelmiminary answer from a notified body, and there seems to be some room for interpretation effectively...

Thanks all, Robert

Hello Robert,

If this is for a mass product there would be another advantage. Let's say someone questions the compliance. They may not relent at all if you counter with lots of technical details and analyzer plots. But if you place a paper in front of them with a stamp and some signatures, stating that this was tested to the EN 300 200 standard by XYZ S.A., they'll probably salute and rest their case.

.=2E.

So, how much is your LO phase noise measured at 10Khz, 100Khz and 1Mhz from the carrier, which is the LO frequency and what is the carrier frequency and SNR you've got after the PLL ? You say non-standard. There are many non standard applications these days. The specification should tell you clear which shoud be the adjacent channel rejection. You can't guess. However -20dB suppresion looks very little for me.

greetings, Vasile Surducan

Hello Vasile,

It's -20dBm, not -20dB below carrier. Depending on the power level it may not be quite trivial to achieve but feasible.