EMRFD Message Archive 5285

Message	Date	From	Subject
5285	2010-09-28 12:12:14	Chris Trask	[emrfd] Re: X-Môde Mixer
> > The X-Môde mixer has a virtual ground for the LO and IF signals at the > diode common cathode connections, and this may be why the X-Môde mixer has > far better IMD performance than the diode ring mixer. > Oh, yes, it most certainly does. I returned the BAC54C diodes to the X-Môde prototype, tested it again to verify the earlier OIP3 measurement, and then added the often neglected isolation resistor to the centre tap of T3. The result is that the OIP3 went from the already published +18dBm to around +25dBm. And this is with a less-than-deal Schottky switching diode and +7dBm of LO. Yo! Mini-Cicuits! Chris Trask N7ZWY / WDX3HLB Senior Member IEEE http://www.home.earthlink.net/~christrask/
5287	2010-09-28 12:35:10	ehydra	Re: X-Môde Mixer
Chris Trask schrieb: > Oh, yes, it most certainly does. I returned the BAC54C diodes to the > X-Môde prototype, tested it again to verify the earlier OIP3 measurement, > and then added the often neglected isolation resistor to the centre tap of > T3. The result is that the OIP3 went from the already published +18dBm to > around +25dBm. And this is with a less-than-deal Schottky switching diode > and +7dBm of LO. Oh. Seems that is really experimental. What was the resistance value? BTW: In your paper you reference the SBL-1 with some values. Are the values measured or just copied over? I would suggest you measure them with the same target board. > > Yo! Mini-Cicuits! > > They made a living of it! - Henry -- ehydra.dyndns.info
5290	2010-09-28 14:37:13	ehydra	Re: X-Môde Mixer
OK, filling the gap until Chris gives new results... Here is a document I memorized and I think it is of interest in this context: http://www.techlib.com/files/RFDesign2.pdf and all the other interesting topics there: http://www.techlib.com/electronics/index.html - Henry -- ehydra.dyndns.info Chris Trask schrieb: >> The X-Môde mixer has a virtual ground for the LO and IF signals at the >> diode common cathode connections, and this may be why the X-Môde mixer has >> far better IMD performance than the diode ring mixer. >> > > Oh, yes, it most certainly does. I returned the BAC54C diodes to the > X-Môde prototype, tested it again to verify the earlier OIP3 measurement, > and then added the often neglected isolation resistor to the centre tap of > T3. The result is that the OIP3 went from the already published +18dBm to > around +25dBm. And this is with a less-than-deal Schottky switching diode > and +7dBm of LO. >
5346	2010-10-05 07:03:36	wa9cgz	Re: X-Môde Mixer
Is it possible to modify the X mode mixer for base band output for use with direct conversion or I/Q SDR where DC through say 50khz possible on the IF output? Joe wa9cgz
5351	2010-10-05 09:55:58	kb1gmx	Re: X-Môde Mixer