[Elecraft] OT: Dayton New Equipment Show

[Don Wilhelm]

I believe Joe is trying to say that traditional test methods fall short 
of reality when applied to direct sampling SDR receivers, and I would 
believe he is correct - there are too many "other factors" to be 
considered (and some of them are yet unknown to most of us).

73,
Don W3FPR

On 5/19/2012 8:57 PM, Joe Subich, W4TV wrote:
>> Guess we will have to await independent testing. The Flex folks seem
>> to assert they have the equivalent of more than 24 bit when dealing
>> with adjacent strong signals.
> Yes we will need to wait for independent testing but given relatively
> wide filters (200 KHz or more), that testing can't be done with only
> two signals.  The tests will need to be (notched) noise power tests or
> multiple tone tests that stress the *total* power handling capability
> of the system.
>
> It is the huge increase in instantaneous peak voltage when multiple
> signals are present that causes multi-channel (multiplexed) power
> amplifiers to be rated for peak powers as much as 20 dB higher that
> their average operating (output) power.  The same problem of peak to
> average power (voltage) *will* impact the absolute voltage handling
> requirements of the ADC used in any DDC system.  Decimation may
> improve resolution but not the absolute maximum and minimum signal
> levels.
>
> 73,
>
>      ... Joe, W4TV
>
>