Heres an update on what I have been doing .
I have been working on a wide bandwitdth filter to remove the switching noise of the switch capacitor filter .
The goal here is not to have a bunch of filter ranges but to have only one , That is why i opted for An 8th order active bessel . I tried many orders of different kinds and this work nice . There will be 3 of these identical filters . Also, I am using the 74hc series now for ultra fast settling and better noise immmunity .
The range of this filter will be from 300 to 20,000 hz .
@ 300 hz the switching component is reduced by lots but still slightly visible , @ 400 its 95% gone , 500 and up its pure sine low low THD . There will be some hand selecting of components here because we are talking less than 1% , E192 resistors from digikey and some hand chosen caps from the electronics store . Asymetry will cause phase distortion and not a pure 120 , perhaps 121,119,120 etc ...
So now that I am even more satisfied with the THD level I am hitting on the pre-amp and amp stage , wich will be much less painful with a good sine . It was a bumpy ride last time because of all the noise induced by my breadboard , and I couldnt even test it on my pcb .
The LMC555 had some duty % stability problems near the higher frequency end it was more like 58/42 wich causes jittery settling time when you change the freq ,I am now using now a new super low drift super high symetry 50/50 duty state of the art oscillator from linear , 50/50 is very important here , the highest we will go is 2.5mhz so I expect the linear IC to be very solid even tho tho I didnt try it yet . 300hz from 20000hz will be selected by 2 x 1M ohm pots , the cap is internal to the IC . For some very fast sweeping . Will make things significantly easier for a PLL add-on .
http://www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1096,P2186 (sot-23 grrr , hate these but I have no choice )
I anticipate this to be EXPENSIVE for those that still wanna purchase one from me , I dont expect much volume here @ all , this is the driver that I will be using for my research .Due to the long man-hours involved here for just making one of these , Istill dont know what I will do with this , perhaps a pcb run that people can buy , obviously before that is done I will have to contact a legal expert and see how I can protect my work from copycats , it will depend on what I can do to somebody who tries to sell my work , I dont want no hydrogen garage con-artists to be undercutting my work . Since I dont have a super-computer that can simulate this beast or a 5000$ licensed simulator with all the exotic parts that you can simply upload , everything had to be ordered from digikey and tested by me here on my breadboard (ouch) . And I tried ALOT of stuff :'( (ouch$).
I have removed the overly complex phase shift oscillator from my pcb due to space limitations and its overall uselessness . I will post it here once I get myself to draw this biitch . My harmonics oscillator will be there tho , for those that are too lazy to make one yourselves . I already posted the schem on this site ... I removed everything that belonged to electrojolt on my pcb , but an add-on will be possible for those who wish to use it with my auto-gate and pulse protection .
