For many years Amateur radio operators use PC audio cards as and ADC, but PC Audio cards are for music and not for SDR applications. The absence of a propely ADC force amateur operators to use audio cards with excellent results never the less the improvement in RF Front-end designs was always limited by the intrinsic limiting factor emebeded in the PC audio cards. The UADC4 brake this limiting factor and elevate the performance of properly ZERO-IF receivers to a new maximum of performance.
The UADC4 born as a decentralized design, done in Canada, Sweden and Switzerland with central coordination in South Africa, the Canadian part was operated by George Boudreau, a well renowned Electronic designer with a lot of experience in SDR radios, he produce the famous Widget SDR radio and several DAC's like ODAC and USB interfaces for audio, in Sweden Leif SM5BSZ place all his experience for more than 50 years into the UADC4, Leif is a well reputed and rigorous Engineer who design the famous SDR WSE units many years ago and he is the worldwide standard lider for SDR HW performance test, he develop the best SDR software "LINRAD", last at not least HB9DRI was in charge of conceptualization, the prototype production and performance test together with Leif, using all my experience accumulated within the last 10 years, we are very proud about the results with the UADC4.
I want to emphasis Leif has no commercial links in any way with the UADC4 or LinkRF, he is just interested in high performance hardware, any endorsement from him is just because the UADC4 cover his expectations, more details you can obtain in an independent way direct from him, he can speak freely about how good or bad the UADC4 is, if you are interested contact him direct for his personal opinion and follow the lower links were you can see the protoype test in his Youtube channel.
The UADC4 has 4 inputs (to support 2 IQ pairs from 2 RF channels) and is able to sampling up to 192KHz, the interface with the computer is done via a USB 2.0 port and support Audio Class 2, means Linux and OS don't need a driver, Windows system required a properly driver but Audio Class 2 is in the latest phase of development for Windows 10, soon you will not need a driver for that.
On January 28, 2018, after conclude intensive test, Leif SM5BSZ upgrade his page "Test on SDR Hardware".
The UADC4 is listed now in place Nr 1 on his list, the numbers could be even much better but the limiting factor was the Front-end mixer, in this case, the Softrock, he modify a little the mixer and the performance increase, never the less the real potential was demonstrated when he test the UADC4 with the WSE converters, obtaining a performance never ever reach with traditional PC sound cards. We can conclude; if the mixer is good enough you can reach 10 to 15dB better performance with the UADC4, now the door is open, with the excellent performance the UADC4 move away the limiting factor from the AD conversion