Open NGDI - Open NextGen Digital Interface

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===Intro===

This project is for the the Ham, the pioneering researcher, the scientist, the DIY audiophile, and anyone else in need of a very high quality digital interface to the physical world. Purpose is to capture the "RAW" output of today's cutting edge high dynamic range ADC's, which operate internally with a "Multi-Bit Delta-Sigma" AKA Sigma-DPCM architecture.

===Preliminary Technical Specifications===

8 Channel Minimum Digital I/O per pcb - up to 32-bit 1.5Mhz PCM + 24.576Mhz (512fs) 1-bit Delta-Sigma to 8-bit Sigma-DPCM
Full hardware/software synchronization, allowing expansion of channels from 8 to 24+ @ 6-bit, 48 to 96+ @ 1-bit. Requires synching of clocks and drivers.
Modular Design. All power supplies local, isolated, and as low impedance as possible. All Analog sections are separate, and will be developed alongside this project. The ADC/DAC will each be implemented on separate PCB's, each format will optimally have it's own ADC/DAC (eg. DSD, PCM, Sigma-DPCM). Analog buffers/preamps will also be separate from ADC/DAC pcb's, similar to the Buffalo line of DAC's. Super Regulators will be developed as well, optimized for speed and low impedance, will piggyback with small daughter boards allowing testing other solutions.

No final hardware choices have been made.

Hardware decisions such as which FPGA, Bus (ie. USB3.0, Ethernet, PCIe/Thunderbolt, etc.), and other major hardware choices need to be decided upon before the design stage begins.

===License===

This is a hardware project, with necessary software (drivers, FPGA code, documentation). This means licensing won't be as simple as an open-source software project, but this project fully wishes to embrace the open-source ideology, and will follow a license which is the closest to the GPL v2 in spirit for the hardware aspects of the project. This means freely distributed, with no restrictions except to give back any modifications made to the community, providing and giving credit to the GPL v2 or any other licenses used.

All software and it's documentation will fall under the GPL v2.
All software and hardware will be open source, including all documentation, which includes PCB layouts, FPGA code, Gerber files, etc.
An open hardware license has not been chosen yet, Either the OSHL v1.0 or CERN OHL v1.2.
Possibly the LGPL for VHDL code, as recommended by the OpenCORES.org

==Software===

There is some necessary software that will be developed. Most important will be a cross-platform driver and basic software to record/playback data. Software for sample rate conversion and DAW software for multi-track recording will be developed.

The Open-NGDAW project aims to create a fully featured DAW capable of handling PCM formats up to 32-bit @ 1.5Mhz, Delta-Sigma and Delta-Mod at up to 512fs (24.576Mhz), and Sigma-DPCM also at up to 512fs (24.576Mhz)

In addition software will be developed for SDR purposes by the Open-NGSDR project.

===Sister Project===

The Main sister project of the Open-NGDI is the OpenNGSDR, a branch specifically for Software defined radio and measurement purposes. It will contain certain hardware extensions not required for general use. All analog stages and ADC/DAC hardware will be external, modular and endlessly configurable.
Open-NGSR or the Open Next-Gen Super Regulator Project will develop modular local supplies.

===Child Projects===

The main child projects will be named *OpenNGADC* & *OpenNGDAC*, there main goals will be to develop external pcb's after choosing an appropriate commercial ADC and DAC. (It is well beyond the scope of these projects to have an ADC or DAC IC fabricated, but the OpenCores site provides possibilities.) This is less critical as alternatives exist for testing functionality, making these projects secondary to this project, but still important. The scope of this project is intentionally large to cover as many bases as possible, with the hope of increasing help in the critical stages of development. The Open-NGDAW will support all formats discussed in a fully featured DAW.

===Community===

No major technical decisions have been made, except minimum sample rates. I hope to make the process very democratic, hopefully giving this project a good opportunity of getting off the ground.

A community will be encouraged to give feedback, idea's and advice. We want to take into account all problems and opinions.

===End Notes===

This project has high goals, but I strongly believe they are attainable. This project has many applications, and I hope will use in many other projects. Only by upping the bar for open-source development will we help spur new generations of technology for public use and education. The developing world and scientists alike will be helped by lowered entry costs into cutting edge research and technology. Though many of the tasks described are within the capability of common USB logic analyzers, this project aims to refine this functionality to the same level given to less "niche" audio formats. The Bandwidth required, though high for audio, is well below uncompressed HD video, and well within the capability of modern computers.

===Future===

With reports of Cryogenic Superconducting Josephson Junctions being used in cutting edge "perfect" High-speed Multi-bit ADC's and DACs, an open-source hardware interface can only help spur advanced research and development. As computing power increases, there is an ever greater need to quantize the world with fine acuity.

===Project Status===