SV: [AMPS] More and More and More and More - drive derived screen potential

[measures]

>
>> A linear does not demand constant gain at any power level, within the
>> context of this discussion
>
>You have an interesting definition of linear then. 

Indeed, Mike, indeed. 

>An "amplifier for SSB"
>may not demand constant gain, but by definition, a linear amplifier does. It
>also requires linear phase but I seldom see a phase/amplitude AM/PM
>conversion or group delay plot for an amateur PA.
>
>The DAF circuit relies on the envelope of the drive signal. If it can peak
>hold well enough then it will appear to be linear. Hence the good 2 tone
>test results. It will also work well for speech as long as the speech has
>sufficient energy to maintain the screen potential nearly constant. The IMDs
>will be a function of the modulation envelope and the time constant of the
>screen supply.
>
>A better way is to use a detector that only biases the valve on when there
>is a signal to amplify, but to ensure no nasty switch on transients, it
>really needs a delay line. This is easy with DSP and is something that
>modern rigs could usefully add to their feature list. The DSP could also do
>useful speech filtering, pre-distortion and compression.
>
Rogers on that, good buddy.  

cheers, Mike


-  Rich..., 805.386.3734, www.vcnet.com/measures.  


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