--- In ham_amplifiers@..., "zerobeat40" <zerobeat40@...>
wrote:
###> The 2 tone test is flawed, and isn't used anymore in the
commercial world. By juggling the spacing of the 2 x tones,
you can hit a .."sweet spot" and come up with really good IMD
numbers.
Z SEZ... That's usually with very wide spacing. At very narrow
spacing, you challenge the power supply bypassing, so the worst
numbers often occur at that test condition.
### Rauch sez the same thing....verbatim on his site...with no
explanation of course.
### OK... what am I missing here ??? I don't "get it". Why
would narrow two tone spacing... "challenge the power supply
bypassing" ??????
### Which supply.... the bias supply and or the HV supply???
What do you mean by "power supply bypassing"..... my giant 100 uf
C filter in my C input HV supply... or something else... like
bypass caps at the base of the plate choke ???
### When I look at the 2 x tone on the scope.... the envelope
varies from zero to full pep.
### What's supposed to happen... if say the two tones are
a multiple of each other... like 1000 hz and 2000 hz..... or 500
hz + 1000hz? This is supposed to be a big 'no-no'. Looks to
me like they would still be .."in phase" regardless of spacing ?
### What 'bad' is supposed to happen if the two tones are say
1000 hz.... and 1120 hz..... or 1000 hz and 1060 hz ??? Is
the 120/60 hz difference freq supposed to modulate the linear
at an audio rate or something ???
I'm completely lost.
later.... Jim VE7RF
