KX3 LO injection

[Dave KK7SS]

Can the USB/LSB carrier point be altered in software?
Why? With most Txcvrs these days one usually has to suffer the intolerable high pitched hiss from a part of the sideband that doesn't really carry any intelligence.

One of the things I do like about the FT-817 in the fact that I can alter the carrier point on USB and LSB sidebands both on Tx and RX.

Just asking <g>

--
Dave G  KK7SS
DN06ig   Richland, WA

'59 Morris Minor 1000
'65 Sprite - in process
'76 Midget - shared with my #4 son.
'06 Honda Civic Hybrid
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[KK7P]

The relationship between the suppressed carrier and the filtering is
defined in the radio's software.  We'll note your request to allow the
radio operator some flexibility in adjusting that during transmit.  In
receive, it is adjustable using the DSP filter controls, just like the K3.

73,

Lyle KK7P

>> Can the USB/LSB carrier point be altered in software?

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[Dave KK7SS]

Lyle,

Thanks for the reply and for turning my question into a request.
Actually, I'd be happy with what I get <G>

>>The relationship between the suppressed carrier and the filtering
>> is defined in the radio's software.  We'll note your request to
>> allow the radio operator some flexibility in adjusting that
>> during transmit.  In receive, it is adjustable using the DSP filter
>> controls, just like the K3.I'm guessing that will also do the job <g>

Just thought I'd ask, as there are two common ways to do it:
One is to shift the filter passband and the other is to adjust the LO injection frequency.

My IC7200 had the 'hiss' problem. Using IF shift would reduce it but would also tend to muffle the audio. Didn't like that. :(

I don't own a K3 so I'm not familiar with it.
But I'll download the manual and do some reading.

Thanks for your time :)

--
Dave G  KK7SS
DN06ig   Richland, WA

'59 Morris Minor 1000
'65 Sprite - in process
'76 Midget - shared with my #4 son.
'06 Honda Civic Hybrid
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[Julian, G4ILO]

Dave KK7SS wrote

Just thought I'd ask, as there are two common ways to do it:
One is to shift the filter passband and the other is to adjust the LO injection frequency.

My IC7200 had the 'hiss' problem. Using IF shift would reduce it but would also tend to muffle the audio. Didn't like that. :(

But shifting the LO injection frequency would worsen the carrier suppression. I used to spend a lot of time fiddling with analog rigs trying to do the same thing. Got it sounding nice, then noticed that when I keyed the mic the output meter was showing a reading even though there was no modulation. :( I run my K3 in SSB with the filter centered on 1.4kHz and it sounds great to me.

[Terry Conboy]

On 2011-06-02 1:25 AM, Julian, G4ILO wrote:

> Dave KK7SS wrote:
>> Just thought I'd ask, as there are two common ways to do it:
>> One is to shift the filter passband and the other is to adjust the LO
>> injection frequency.
>>
>> My IC7200 had the 'hiss' problem. Using IF shift would reduce it but would
>> also tend to muffle the audio. Didn't like that. :(
> But shifting the LO injection frequency would worsen the carrier
> suppression. I used to spend a lot of time fiddling with analog rigs trying
> to do the same thing. Got it sounding nice, then noticed that when I keyed
> the mic the output meter was showing a reading even though there was no
> modulation. :( I run my K3 in SSB with the filter centered on 1.4kHz and it
> sounds great to me.
>
> -----
> Julian, G4ILO. K2 #392  K3 #222.

I suspect the KX3 will use the equivalent of the so-called "phasing
method" of SSB generation (but digitally, in DSP software).  I don't
think there will be a xtal filter like in the older analog radios, so
the carrier suppression shouldn't change.  All of the filtering (except
perhaps for the baseband "roofing filter") will probably be via DSP.

Eventually, the Elecraft guys will give us more details of the radio
design so we can eliminate the guesswork.

Keep clam,
Terry N6RY

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