On the Si570 Group Buy page at: http://www.softrockradio.org/
The specs there imply the LVDS version of the Si570 has 20ppm stability vs. 50ppm for the CMOS Si570. This is a significant advantage to the LVDS part in my opinion. There are some studies of phase noise by Mike Collins KF4BQ in the Files area. If my whiskey-soaked memory serves, the LVDS Si570 does outperform the CMOS version in the tests, but it is arguable the differences will be noticeable on HF in my opinion. Given the LVDS part is only $2 more than the CMOS part, and it is cleaner and significantly more stable. One would wonder why the CMOS part would ever be used with a SRLite. Comments? 73's David --- In [email protected], k5nwa <[EMAIL PROTECTED]> wrote: > > At 01:42 PM 5/3/2008, you wrote: > > >So what is the advantage of the LVDS part over the CMOS one? > >According to the spec, max current drain is not much different, but > >the LVDS part supports much higher frequency output. Does it also > >have a cleaner output? > > > >On May 3, 2008, at 11:17 AM, k5nwa wrote: > > You got it, the LVDS has a much higher frequency range and it's > output is cleaner by a bit, but it appears from reports that the CMOS > version is clean enough for most peoples usage. > > A LVDS signal can be also sent a fair distance over twisted pair > wiring without degrading, CMOS does not have such an option. On my > initial test the LVDS chip was connected to the SoftRock with a 3' > CAT5e unshielded twisted cable pair and the signal was clean, it > worked fine with a 10' cable also. > > > Cecil > K5NWA > www.softrockradio.org www.qrpradio.com > > "Blessed are the cracked, for they shall let in the light." >
