Re: New overview ARRL/QST Product Reviews
- Hello Nico,
I would be glad to change the figures when they have been published in ARRL/QST, because this is my source. What Jay sent me I immediately corrected in my overview.
Otherwise Mr. Icom, Kenwood, TenTec, Yaesu, etc. will ask me to change their figures too...
I follow discussions where Rob Sherwood is being involved with more than great interest, but only act according the publications in ARRL/QST.
73! Hans PA1HR.
--- In perseus_SDR@yahoogroups.com, "iv3nwv" <nicopal@...> wrote:
> --- In perseus_SDR@yahoogroups.com, "PA1HR" <hans@> wrote:
> > I corrected my overview and just published it.
> It's still inconsistent, Hans
> If you understand the figures you have published and if you agree that the sensitivity of a receiver has nothing to do with a two-tone test signal spacing you have the following options:
> 1) Correct the Perseus IP3@2kHz.
> If the DR@2kHz is 3 dB less than that at 20 kHz spacing, the IP3 should be 4.5 dB lower than published, that's to say 30.5 dBm and not 35 dBm.
> 2) Correct the Perseus DR@2kHz.
> If the IP3@2kHz does not differ from the 20 kHz value, the DR@2kHz should equal the value at 20 kHz spacing.
> I leave the choice up to you, but if you prefer the option #2, you should place the Perseus at rank 4 instead of rank 7.
> Leaving the table as it is would be the worst option.
> You can also compare ARRL figures with those published by Rob Sherwood:
> Rob did not measured any difference in the DR figure of Perseus when the spacing is changed. Which is what usually happens in a direct sampling receiver.
> Nico / IV3NWV
- Hi Leif,
I agree that my two tone IMD2 example was wrong. As long as I test with nearly perfectly periodical signals (thus with a very small bandwidth) there is always enough oversampling for all spectrum components.
> I do not understand the theory behind this statement,I just wanted to express that NL reduction by dithering needs a high ratio of the dithering bandwidth (finally limited by the sample rate) to the signal bandwidth (RX bandwidth). While a linearization scheme working with postdistortion based on a physical model of the ADC can be inherently wideband.
> (or I do not understand the statement.) More relevant
> is that I find something else when actually doing the
But I agree that this has no relevance for shortwave reception of narrowband signals.