4DSP Support Forum

Products => FMC Products => FMC30RF => Topic started by: malles on September 08, 2014, 11:00 AM

Title: 60 MHz bandwidth with FMC30RF
Post by: malles on September 08, 2014, 11:00 AM

Hi,

how exactly do we bypass the Low Pass Filter of the TRF3711 in order to be able to operate with up to 60 MHz bandwidth as mentioned on the web site of the board? We see a performance degradation when operating at 25+MHz and think that this might be related to this.

Thank you,
Matthias

Title: Re: 60 MHz bandwidth with FMC30RF
Post by: malles on September 09, 2014, 04:50 AM

Hi again,

I had a look at the datasheet of the TRF371125 chip. The cutoff frequency of the chip in bypass mode is said to be 30 MHz (it's the 3dB point). If the low-pass filter isn't bypassed it's at most 20 MHz. So is it even possible to achieve 60 MHz (as promoted) at all?

Thanks,
Matthias

Title: Re: 60 MHz bandwidth with FMC30RF
Post by: iklink on September 09, 2014, 10:38 AM

Dear,


You are right that the cutoff frequency in bypass mode is 30MHz on each output of the TRF3711. If you use I and Q, the total bandwidth can be upto 60MHz, however you will have to downconvert completely to baseband. So you will have to set the LO frequency to the center of your RF signal.


Best regards,
Ingmar van Klink
4DSP

Title: Re: 60 MHz bandwidth with FMC30RF
Post by: arnaudNL on September 11, 2014, 09:33 AM

Dear Matthias,


Was the information sufficient, can I go ahead and close this topic?


Best Regards,
Arnaud

Title: Re: 60 MHz bandwidth with FMC30RF
Post by: arnaudNL on September 15, 2014, 04:46 AM

Dear Mathias,


I will proceed with closing this topic in 24 hours from now without feedback from your side.


Best Regards,
Arnaud

Title: Re: 60 MHz bandwidth with FMC30RF
Post by: arnaudNL on September 17, 2014, 07:35 AM

This topic is being closed because the issue is considered as resolved by 4DSP. Feel free to create a new topic for any further inquiries.