Shift register driven by a 12x clock. The 6 outputs loaded with weighted resistors to produce a sine-like waveform.
Network output fed, via a unity gain buffer to a 6-pole LP Butterworth active filter designed (FilterLab) for Fc 1150 Hz.
My intention is to use for a sinewave between 10 Hz and 1 KHz.
After testing I found that below 200 Hz the output is bad, coming to almost copy the step-like input!!
Besides revising the design with FilterLab and the hardware, I simulated it, confirming de bad performance at the lower end. LT's .asc file attached.
The board is already populated and the number of opamps (1 x TL074) thus fixed.
Any chance to improve it? Otherwise I will have to throw the board (veroboard) which took me ages to assemble. Vessels are too demanding ladies...
If anyone recall a similar question of mine from some years ago, please note that I never managed to built that circuit so better to forget that thread and start afresh here again.
Thanks for any help and the comprehension.
Yes, a follow-up would be asking how to actually center the sinewave at 0V but oviously better to solve this first.
Gracias again.
Network output fed, via a unity gain buffer to a 6-pole LP Butterworth active filter designed (FilterLab) for Fc 1150 Hz.
My intention is to use for a sinewave between 10 Hz and 1 KHz.
After testing I found that below 200 Hz the output is bad, coming to almost copy the step-like input!!
Besides revising the design with FilterLab and the hardware, I simulated it, confirming de bad performance at the lower end. LT's .asc file attached.
The board is already populated and the number of opamps (1 x TL074) thus fixed.
Any chance to improve it? Otherwise I will have to throw the board (veroboard) which took me ages to assemble. Vessels are too demanding ladies...
If anyone recall a similar question of mine from some years ago, please note that I never managed to built that circuit so better to forget that thread and start afresh here again.
Thanks for any help and the comprehension.
Yes, a follow-up would be asking how to actually center the sinewave at 0V but oviously better to solve this first.
Gracias again.