--- In [email protected], "rhblumeng" <[EMAIL PROTECTED]> wrote: > > "I can say conclusively that a weak SSB and CW signals are generally > more readable/more comfortably readable listening through the digital > filters of the SoftRock/Rocky or KGKSDR/Delta 44 than through the > crystal filtering of the FT1000 when there is QRN/static crashes > present. As the FT1000 receiver is widely regarded as one of the > best lowband weak signal receivers, owing to its excellent cross mod > performance and filtering, this says a lot for how far digital > filtering and processing has come." > > I wonder if anyone has an opinion as to how much of the better > performance is due to the digital filtering and how much might > actually be the different detection offered by IQ and the software? > > Bob
Bob, in the case of the 1000D that's quite a possibility, referred to the demodulation done by via software instead of a conventional product detector. In the case of the Mark-V, you have both the possibilites. You can continue to use the standard product detector, or use the EDSP (as Yaesu calls it) that performs the demodulation and filtering in software. I own a Mark-V and have compared many times this rig to a prototype of the new SDR-X that will be shortly marketed by WoodBox Radio. Irrespective of what demodulator I have set in the Mk-V, I find the SDR-X, how to say, a bit more clear and limpid. But IMHO this is caused by the fact that in the SDR-X there are no crystal filters with their non-constant group delay and non-linear phase response. The real advantage of a direct conversion software defined radio is just that, the lack of the distortion induced by the use of crystal and/or mechanic filters. 73 Alberto I2PHD
