Delta Sigma Modulator to convert vinyl to DSD

[merlin el mago]

I want to rip vinyl to DSD so I guess I only need a Delta Sigma Modulator but I'm newbie & I don't know how to do it myself, please help.

I read this papers on subject:

http://www.beis.de/Elektronik/DeltaSigma/DeltaSigma.html

http://dsd-guide.com/sites/default/files/white-papers/DSD%20-%20the%20new%20addiction%20-%20v2.pdf

http://thewelltemperedcomputer.com/KB/DSD.htm

http://samplerateconverter.com/content/how-work-sigma-delta-modulation-audio


TIA
Felipe

 

[MarcelvdG]

That's rather ambitious; building your own first- or second-order delta-sigma modulator is not difficult, but because of the low oversampling you will need something of a far higher order for DSD.

 

[merlin el mago]

Thanks for answer, do you have schematics?

 

[MarcelvdG]

For what it's worth I've added a schematic and a system diagram.

The schematic is a simple sigma-delta modulator I once built to functionally test a single-bit DAC. I doubt if it going to be of much use because its distortion performance is not very good and because it runs at 28.224 MHz, equivalent to DSD640 rather than DSD64. The bottom left D-flip-flop, the NOR gate and the third-order Butterworth filter are actually a simple single-bit DAC to test the sigma-delta modulator.

The other attachment is a system diagram for a fifth-order sigma-delta proposed by Sony for DSD64. Its coefficients are b1 = 1, b2 = 0.5, b3 = 0.25, b4 = 0.125, b5 = 0.0625, c2 = -0.001953125 and c4 = -0.03125.

Again this won't help you much, because to make such a sigma-delta, you would have to translate its loop filter into an equivalent continuous-time filter and to make a circuit implementation of it. You would also have to add clippers or reset circuits to get it to recover properly from overload. This would be quite some work and I don't believe it would be a suitable project for a newbie.

 

[merlin el mago]

Thank you.