Ryan, As Jonathan said, we have been testing the adc1x5000-8. I would also like to hear about your approach. We don't see such large core-to-core differences as you suggest and the improvements I have been able to achieve have been minimal from the point of view of a radio astronomy correlator. The main improvement has been in reducing the spur at 1/4 of the sample frequency (the EV8AQ160 has 4 cores).
One of my Bell Labs friends told me about a company (in Finland if I remember correctly) which sells IP for FPGAs which breaks out the samples from the 4 cores and separately frequency compensates them before re-assembling the input stream. The improvement for communications signals was only a few dB, however. Bob Wilson On Tue, May 29, 2012 at 12:20 AM, Ryan Monroe <[email protected]>wrote: > I've used the ADC083000s before and the interleave can be pretty bad-- as > much as 15% difference across their 3GHz spectrum! You should expect > better performance because you only need to tune for 1GHz of bandwidth > however. I can't speak for the other parts. > > I have a technique I've developed which cancels out all cross-board ADC > interleaving issues. I've been trying to get JPL to let me release it to > the public domain: I'll see what I can do, and please tell me if you have > issues. > > --Ryan Monroe > > > > > On 5/28/2012 5:47 PM, Dan Werthimer wrote: > >> hi bill, >> >> i think all the boards you mention have analog bandwidth out to 2 GHz, >> so they should work well for your 1-2 GHz band. >> >> the asiaa board is the least expensive, but this board does not have >> programmable >> attenuators like the Kat-ADC. the asiaa board can be used as a single >> 5 Gsps ADC, or as a dual 2.5 GHz ADC. >> we have used the asiaa board as a single 5 gsps adc, and it works quite >> well. >> but we have never tested it as a dual adc - perhaps others reading >> this email can >> give you advice about using it in dual mode. if you are using roach >> I, you can't >> get the 8 bit version of the asiaa board working at the full 5 gsps. >> if you are using >> roach II, you can use it at 5 Gsps. >> >> best wishes, >> >> dan >> >> >> >> >> On Thu, May 24, 2012 at 11:30 AM, Bill Petrachenko<[email protected]> >> wrote: >> >>> I'm designing a digital data acquisition system using a ROACH1 board. I >>> need >>> to sample two Nyquist zones at 1024-2048 MHz. It appears that in the >>> Casper >>> group of products, a pair of ASIAA, ADC1x3000-8, or KatADC boards would >>> work >>> well and nicely interfaced to a single ROACH1 board (although the ASIAA >>> board is not mention explicitly on the web-site). Is there any reason to >>> choose one board over another? The gain adjustment stage is attractive on >>> the KatADC but the performance of the ADC1x3000-8 chip seems marginally >>> better at 2-GHz input frequency. The e2v chip seems less established than >>> the National chips. Is interleaving or calibration an issue for any of >>> the >>> chips? >>> >>> I'd be grateful for any opinions on this. >>> Thanks, -Bill. >>> >> > >
