It could be a phase noise problem. The phase noise is mainly present closed to the LO carrier. Using an IF of some kHz protect the mixer from the noise, the phase noise decreasing quickly as soons as we live the foot of the carrier. When using "zero IF", the LO noise could be a major problem.
Gérard/F6EHJ ----- Original Message ----- From: "Per-Tore Aasestrand" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Monday, October 31, 2005 10:05 AM Subject: Re: [soft_radio] What is the best way in a SDR? > The same is done by R&S and WJ. > Would there be any benefit in doing the DSP at a higher IF? > > P-T > > At 09:54 31.10.2005, you wrote: >>----- Original Message ----- >>From: "Juan EA7FNJ" <[EMAIL PROTECTED]> >>To: <[email protected]> >>Sent: Sunday, October 30, 2005 11:26 PM >>Subject: [soft_radio] What is the best way in a SDR? >> >> >> > Hi guys. >> > >> > I have a question: >> > >> > What is the best way: >> > >> > - Input the IF signal to a ADC and make all the process by DSP >> > >> > or >> > >> > - Input the I/Q signal from the Tayloe Mixer to a ADC and DSP >> >>FWIW, when I worked for Racal they used the first technique. They used a >>low >>IF, something like 30 kHz, IIRC. >> >>Leon >>-- >>Leon Heller, G1HSM >>[EMAIL PROTECTED] >>http://www.geocities.com/leon_heller >> >>--- >>[This E-mail has been scanned for viruses but it is your responsibility >>to maintain up to date anti virus software on the device that you are >>currently using to read this email. ] >> >> >> >> >> >>Yahoo! Groups Links >> >> >> >> > > > +-----------------------+------------------------------+ > | Per-Tore Aasestrand | E-mail : [EMAIL PROTECTED] | > | P.O. Box 1708 Nordnes | Voice : + 47 - 55 32 32 35 | > | N-5816 Bergen, Norway | Mobile : + 47 - 92 04 44 76 | > +-----------------------+------------------------------+ > > > > > > Yahoo! Groups Links > > > > > > > > > ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/ELTolB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
