The Well synchronized asynchronous FIFO buffer - Slaved I2S reclocker

Thanks.

Im no technician, but i listen. So in my case: Rpi with replaced onboard regulators and supplied 1.8, 3.3 and 5v clean linear power, has Ian's IsolatorPi to output "clean I2s", then i2s signal to Ian's Fifo then to Ian's isolator again, then to Ian's dualxo board (with your old driscoll xo), then to my dac - i still felt obvious sound changes after ufl connection between Rpi and Fifo and also after ufl connection from Fifo to isolator to Dualxo board. All devices are powered with very high quality lineqr power supplies.
So my subjective opinion, that his isolators are still prone to let source and also airborn picked noise through.. and therefore both sides ufl connections carry big benefits.

Hope to try your fifo and finally hope to get proper isolation of the source.

There is a great difference between our FIFO Lite and Ian's FIFO: the FIFO buffer is slaved to the master clock that resides in a different time and electrical domain.

In our FIFO the LRCK comes directly from the master clock, it does not cross the FPGA, so it's well isolated from the source.
 
To clarify better, let examin a 3 bit ladder DAC as example.

Thermometer/Dec/Switch at 1 time
0000000 0 -
0000001 1 1
0000011 2 1
0000111 3 1
0001111 4 1
0011111 5 1
0111111 6 1
1111111 7 1
always 1 resistor at 1 time

R2R/Dec/Switch at 1 time
000 0 -
001 1 1
010 2 2
011 3 1
100 4 3
101 5 1
110 6 2
111 7 1
4 times 1 resistor at 1 time
2 times 2 resistors at 1 time
1 time 3 resistors at 1 time

Just curious, wouldn't gray code do the trick, or at least improve on pure R2R?
 
Preliminary measurements

I attach some phase noise plots of the FIFO Lite:
- MCLK output
- BCK output (FIFO Lite + Reclocker)
- LRCK output
- Comparison (including the base DRIXO 24.576 MHz oscillator)
 

Attachments

  • MCK 24576.png
    MCK 24576.png
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  • BCK 3072 FIFO + Reclock with Drixo24576.png
    BCK 3072 FIFO + Reclock with Drixo24576.png
    129.6 KB · Views: 368
  • LRCK 192k with Drixo24576.png
    LRCK 192k with Drixo24576.png
    125.9 KB · Views: 369
  • DRIXO 24M vs FIFO MCK vs FIFO + reclock BCK vs FIFO LRCK.png
    DRIXO 24M vs FIFO MCK vs FIFO + reclock BCK vs FIFO LRCK.png
    172.6 KB · Views: 387