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This a framework to test new ideas in transmission technology. Actual development is a LDPC-coder in

rrc_complex
===========


This module is used to interface the ICS-cards in a fast way. The
operations done here should be put in the cards FPGA later.
 For the reception-part, two versions exist: one for an 'optimal'
receiver (all samples aligned), another for the ICS-receiver, which
has the samples all mangled up...
 There are different possible pulse-shape filters available. You can
find them in the file rrcs.[ch], where you can also add your own
filters. The following points are important:
- The peak has to be in the middle
- The filter should cut half the spectrum
- The filter should be short, for optimality...


rrc_complex_ics_rcv
-------------------

Downsamples by a factor of 2. One can chose to apply a filter before, or
not. This is for the output of the ICS-card, which is probably thought
to support complex I/Q-data. But we get direct I/Q-data on each input
channel, so the format has to be adopted.
 An important parameter is 'channel', which says whether it's an even or
odd channel. This is due to the ICS-hardware...

Inputs:
	SYMBOL_COMPLEX_S32

outputs:
	SYMBOL_COMPLEX

Config:
	channel<int>: 0
		Which channel to decode

	conv_rrc<int>: 0
		Apply the conv_rrc
		0 - no filtering
		1 - filtering

	rrc_index<int>: 0
		Which of the rrcs to use

	shift<int>: 0
		Shift the input by this many samples

	shift_left<int>: 12
		How many bits to shift left


rrc_complex_rcv
---------------

Downsamples by a factor of 2. One can chose to apply a filter before, or
not.

Inputs:
	SYMBOL_COMPLEX

outputs:
	SYMBOL_COMPLEX

Config:
	rrc_inv<int>: 0
		Apply the rrc_inv
		0 - no filtering
		1 - filtering

	shift<int>: 0
		Shift the input by this many samples


rrc_complex_send
----------------

Takes a signal and upsamples it by a factor of 2, putting an RRC with
roll-off factor of 0.22 on it.

Inputs:
	SYMBOL_COMPLEX

outputs:
	SYMBOL_COMPLEX

Config:
	amplitude<double>: 1
		What amplitude

	rrc_index<int>: 0
		Which of the rrcs to use