advanced audio recording
an optimized R2R-DAC with 0,5% precision
  DSP Module

A simple R2R-based DAC for signal generation in audio and video applications with 0,5% error is shown belw. It is based on standard "golden" resistors with 5% tolerance. The circuit is controlled by up tp 10 bits using a current Spartan 2 FPGA from Xilinx.

R2R-DAC Jürgen Schuhmacher 2005
10-Bit-DAC with calibration option

Calibration method:

6 Bits of a common R2R-32-Step-DAC are extended by additional 4 bits with optimized values R4,R6,R8 to be able to calibrate any deviation from the ideal curve. The calibration range is +/- 5,2% which is enough if at least the most important two resistors meet in values well enough. In case more compensation is required, the B-Pins have to be shifted one position to the right using the values R6, R4, R2,R2.

Application examples:

 With the Spartan FPGA, a highly precise signal generator can be built running at 48MHz which is almost suitable for simple audio output using oversampling strategies and pulse density modulation methods possibly using for bass frequencies when adding good filtering.
YC-Video can be generate easily with high quality too.

See an example for a noise generator using this ladder:
Noise generator in a FPGA

 Read more about the R2R-DAC here: optimized 8 Bit DAC



48 kHz
Audio DSP


© Jürgen Schuhmacher , Sound of L.A. Audio Productions 2005