Re: Airspy architecture

Alberto I2PHD

On 2/2/2015 1:37 PM, 'siegfried jackstien' siegfried.jackstien@... [airspy] wrote:

I would guess the if n and if p means if negative and if positive (balanced
output) and NOT be I/Q signals

The r820t tuner does only have low if out and not 0hz if (i/q)
Yes, that was also my first guess, but the high image rejection made me wondering...
And in any case you can have I/Q outputs also if the IF is not at zero.

On 2/2/2015 3:45 PM, Leif Asbrink leif@... [airspy] wrote:

The R820T2 has I and Q internally and combines
them to a real valued signal with excellent image

The output is balanced to fit the balanced input 
of typical AD converters.

I have no idea how they can get such a good image
Hi Leif,

� That explains a lot. From the simplified block diagram found on Internet the use
of a quadrature mixer is not apparent, and that made me scraping my head...

Yes, achieving 65 dB of image rejection working in the analog domain is really
a feat... kudos to them... everything must have been balanced with extraordinary

Thanks Sigi and Leif.

73 Alberto I2PHD
Credo Ut Intelligam

This email has been checked for viruses by Avast antivirus software.

Join to automatically receive all group messages.