Hi Jim, > needing an excuse to buy a dual > core CPU, my thoughts turned to SDR and writing a program that can > handle TWO or more separate IQ streams from a 4 or more channel sound > card (or 2 cards) and summing them together ... if each stream has its > unique digitizing noise, a potential 6 db of noise floor improvement > could be had ... and with SDR front ends so inexpensive, this dual > channel could be extended to the antenna ... just a thought ... anyway This feature has been present in Linrad from start with 4 audio inputs and the WSE hardware has the 2 RF channels needed:-)
The two channels are combined for optimum S/N in the computer. In case both channels are fed from the same antenna, the signals will add coherently to increase by 6 dB while the random noise from digitation process as well as from amplifiers in the radio hardware will increase by 3 dB. This means that the dynamic range increases by 3 dB. You do not need a dual core computer for this:-) Linrad was designed to run on a Pentium III.... On a single core Pentium IV you can run several issues of Linrad simultaneously if you wish. The modern computers are fantastic:-) 73 Leif / SM5BSZ
