SDR-Widget


SDR-Widget::What is it:

The SDR-Widget is an attempt to create an open-source audio/control card for the Amateur Radio SDR enthusiast. The design is based up the AK5394A ADC, CS4344 DAC and the Atmel AT32UC3A3256 processor.

Hardware Features:
  • Compact 3" x 2.5", 2 board stack. 3.5mm audio connections.
  • Powered from the USB port, no external power supply needed
  • 24-bit AK5394A ADC - the premier audio ADC in commercial use today
  • CS4344 ES9023 24-bit DAC
  • I2C control bus
  • 16-bit LCD panel interface (configured for 4-bit) with drivers for HD44780 based 4-line displays
  • Connector for quadrature rotary encoder input (with push switch)
  • 3 optocoupler buffered inputs
  • 3 mosfet 'contact' outputs
  • Firmware update via USB port
  • JTAG port
Software Features (either present or coming soon)
  • USB composite device with audio I/O, control and CDC channels
  • Supports USB Audio class 2 (480mbs) on the latest Linux -rc kernel as well as the latest MacOS
  • Support 24-bit 48k/96k/192k sample rates on Linux and MacOS. Requires an ASIO driver when used with Windows OS.
  • Support USB Audio class1 on Windows at 48k sample rate.
  • Has an integrated CDC, Communications Device Class, channel for debug messages
  • A superset of the DG8SAQ control interface
  • 4-line LCD message engine
  • Menu system with selection control via external rotary encoder and switch.

Performance:

The Beta version of the SDR-Widget has outperformed, for noise floor, all commercial sounds cards tested (Creative X-fi 5.1, E-MU 0202, FA-66, M-Audio Audiophile 192) The noise floor with shorted inputs is approximately -135db.

Build difficulty:

The kit uses 0805 sized SMT components and has a LQFP144_20 cpu. The kit requires a steady hand and a measured approach to building. It is not impossible for a beginner to build the kit but it is not recommended. Currently, there are no 'instructions' on how to assemble the kit. Schematics and component placement are the only aids provided.

The kitting system is rudimentary but functional. Kits will be shipped as first class mail in 2 bubble mailers


Prices and Ordering:

I am sold out of full kits for the SDR-Widget.

There has been enough in interest in the design that I am offering the blank circuit boards and the difficult to obtain ES9023 DAC as a package. The full BOMs with Digikey part numbers are available online at:

UC3A3 CPU card BOM
AK5394 ADC card BOM
Document Archive. This archive contains schematics, component layout






Alpa version of the SDR-Widget with optional LCD display