VGAtoBaseband

         

VGAtoBaseband Release status: experimental [box doku]
Description	use the VGA port to generate I/Q baseband signals
Author(s)	siro
Last Version	0.1 ()
Platform	Evil Hack
License	GPL
Download	[1]

Requirements

• PC with VGA adapter
• OpenGL with Direct Redering
• Vsync enabled
• Software-defined Radio Transmitter that generates I/Q Signals
• GL_ARB_fragment_program to use the low-pass filter
• GL_ARB_pixel_buffer_object for efficient CPU to GPU transfers

Linux

• Mesa 9.0 (other drivers are untested)
• X-server

Windows

• Windows XP doesnt work
• other OS are untested

Software

This software generates analog I/Q Signals that can be feed into a rf-modulator. The current version is only working with 8Mhz * 8/7 symbolrate = 9,1428 MSymbols/s. A symbols contains an I and Q value. It is possible to use fragment shader to low-pass filter the signal, simply pass the -filter argument. The I/Q values are feed using a unix fifo / a file. 8 byte form two 32bit floats, that equals a complex number. The values have to be between 0.0f and 1.0f. The complex value is assigned to the RED and GREEN channel, while the BLUE channel is set to 0.5f. 8bit and 10bit VGA Graphic cards are supported.

Libraries

• freeglut3-dev
• libglu1-mesa-dev
• libgl1-mesa-dev