Re: [TenTec] Re: [Orion] Orion Synthesizer speed

[Bob Henderson <bob@cytanet.com.cy>]

I guess you guys missed my post on this at the end of December.  I spoke 
to Ten Tec about the jerky synthesiser response and they confirmed it to 
be nothing to do with slow locking of the synthesiser, whether in the 
interests of low noise or anything else.  The effect is caused by the 
speed with which the control microprocessor can execute instructions.  
The comments made by Ten Tec on this issue are attached below:-

(TT)  The tuning is limited by the amount of overhead in the 
microprocessor, not the synthesizer lock time.

(TT)  Tuning in the Orion was patterened after the Jupiter, which was 
quite acceptable. However, the Orion microprocessor controls many more 
operations and features. The encoder outputs 512 pulses. When tuning 
rapidly, if the microprocessor cannot immediately act upon the tuning 
pulse, the pulses are counted and when there is a break, it updates the 
frequency. That's why rapid tuning sounds different. I understand that 
there are those who would prefer smoother and faster tuning. It is on 
our "wish list" but we have been working on items that we feel are of 
greater interest to more hams.


73  Bob, 5B4AGN, P3F


Jim Reid wrote:

> Comment made:
>
>  
>
> > (4) The synthesizer seems to lock slowly, making rapid 
> > frequency excursions  sound jerky.  Most other modern rigs 
> > have fast enough synthesizers that the  tuning seems 
> > analog. Too bad the Orion can't do this as well.
> >    
>
> I believe that this is "on purpose".  As I think I understand,
> from prior posts on this issue,  in exchange for a slower
> synthesizer,  we are given very much lower "close in"
> phase noise which enhances very weak signal detection
> (also,  very low transmitted phase noise as well).
>
> This is a DX'ing trade off some appreciate;  not sure about
> contesting as I don't do that.  Fast synthesizers are also
> broader bandwidth,  thus more noise  into the signal
> path.  Other functions perhaps "compromised" by this
> design decision might be the encoder tuning rates and
> step size combinations in the "default" design.
>
> There is much more "under the hood" of this creature
> that I am still learning/discovering even though I have
> had my Orion since the middle of last May!
>
> BTW,  downloaded Carl M's,  N4PY,  V1.07 Orion control
> software this morning.  Now we can adjust AGC Threshold
> as a "panel" adjustment anytime we wish!  It is now a "virtual"
> front panel operator control without need to go into the AGC
> menu.  And this can be done when using any of the slow,
> med,  fast,  or prog. AGC selections.  Also,  the selected
> threshold is "remembered" by band when QSY'ing.
> Very neat added function by Carl.
>
> 73,  Jim  KH7M
>
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>  



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