[Elecraft] Re: Re： Diversity Receive as Noise C anceling?

[Edward R. Cole]

I'm not sure that adapting the sw for noise 
cancellation will take that much extra 
processing.  Reversing phase is a simple digital 
inversion.  Adjusting amplitude is already done 
on both receivers.  Continuous phase shifting for 
the sub-Rx might take some processing, but probably not as much as you guess.

But the K3 will likely get an upgraded cpu chip 
someday, due to continuous improvements in 
firmware.  Would that be a DSP board?  Elecraft 
seems to have their radios configured for continual upgrading. (nice!).

73, Ed - KL7UW

At 10:52 PM 11/29/2010, Johnny Siu wrote:
>Hello Edward, This will depend on how much 
>'brain power' is left in the DSP. 
>  Apparently, currently, quite a work load of 
>the DSP has been used to eliminate the internal 
>birdies. Having said that, thanks for the 
>modular design of K3, a 'heart-transplant' of 
>exchanging the DSP board with more powerful 
>version may be feasible. Â cheers, Johnny VR2XMC 
>----- 郵件原件 ---- 寄件人﹕ Edward R. 
>Cole <kl7uw at acsalaska.net> 收件人﹕ 
>olaf.devik at mollefaret.no 副本(CC) 
>Elecraft at mailman.qth.net 傳送日期﹕ 
>2010/11/30 (二) 3:44:10 PM 主題： Re: 
>[Elecraft] Diversity Receive as Noise Canceling? 
>At 10:06 PM 11/29/2010, you wrote: >Noted your 
>comment on noise reduction by phase nulling. 
>Have you >looked on info on pages by pa0sim, see 
>www.pa0sim.nl, he has done >more or less what I 
>think you are considering. Ie connecting 
>the >output from 2 phase locked receivers fed 
>with separate antennas and >do the 
>amplitude/phase nulling at AF level. > >Some of 
>the sound samples on his website are impressive 
>in terms of >noise reduction. > >I would love to 
>see an application which could do this, would 
>be >nice to check out if phase nulling works at 
>a site before trying an >MFJ unit or similar. I 
>really would like to see this done in the K3 >as 
>all the hardware is there to do such 
>phasenulling in software, >could eg use the VFO 
>B knob for phase control and the volume 
>knobs >for amplitude control. Only requirement 
>is to feed the 2 RXs with >separate antennas, ie 
>an alternative use of diversity capability. > >I 
>was not able to respond on the reflector. Would 
>be nice if you >could keep the group updated if 
>you get more info on this. > >73 de Olaf LA3RK 
>Olaf, Thanks for writing.  I somehow lost your 
>e-mail and wanted to look at the pa0sim 
>webpage.  I merely suggested the idea.  I 
>really have no prospect for doing this.  I 
>thought maybe Elecraft might be interested in 
>the idea; provide firmware to do it. A 
>modification on doing diversity reception was 
>what I had in mind.  Use a small "sniffer" 
>antenna on the aux Rx input to sample noise and 
>null it from the main receiver in sw.  I think 
>it would be easiest to accomplish in digital 
>before conversion to audio.  All the DSP 
>routines are done there:Â  NB, NR, AGC, APF, DSP 
>bandwidth.  Phase shift and amplitude 
>adjustments would be possible in digital, so 
>assigning VFO-B would be relatively simple for 
>phase and use the sub-Rx volume for amplitude 
>adjustment. I guess it's now up to Elecraft if 
>they want to explore this. 73, Ed - KL7UW, 
>WD2XSH/45 ======================================


73, Ed - KL7UW, WD2XSH/45
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