CCSDS Encoder Definition: Difference between revisions
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[ | CCSDS Encoding class for convolutional encoding with rate 1/2, K=7, and polynomials [109, 79]. | ||
Uses Phil Karn's (KA9Q) implementation of the CCSDS encoder for rate 1/2, K=7, and CC polynomial [109, 79]. These are non-adjustable in this encoder. For an adjustable CC encoder where we can set the rate, constraint length, and polynomial, see [[CC Encoder Definition]]. | |||
== Parameters == | == Parameters == | ||
(''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span> | (''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span> | ||
; | ; Parallelism | ||
: | : It seems that one can create a tensor of one or two dimensions of encoders. More info is needed on this. | ||
; Dimension 1 | |||
: Active when parallelism > 0 | |||
; Dimension 2 | |||
: Active when parallelism > 1 | |||
; Frame bits | |||
: When not being used in a tagged stream mode, this encoder will only process frames of the length provided here. If used in a tagged stream block, this setting becomes the maximum allowable frame size that the block may process. | |||
; Start state | |||
: Initialization state of the shift register. | |||
; | ; Streaming behaviour | ||
: | : Specifies how the convolutional encoder will behave and under what conditions. | ||
:; Streaming: This mode expects an uninterrupted flow of samples into the encoder, and the output stream is continually encoded. | |||
:; Terminated: Mode designed for packet-based systems. This mode adds rate*(k-1) bits to the output as a way to help flush the decoder. | |||
:; Tailbiting: Another packet-based method. Instead of adding bits onto the end of the packet, this mode will continue the code between the payloads of packets by pre-initializing the state of the new packet based on the state of the last packet for (k-1) bits. | |||
:; Truncated: A truncated code always resets the registers to the start state between frames. | |||
== Example Flowgraph == | == Example Flowgraph == | ||
| Line 21: | Line 37: | ||
; C++ files | ; C++ files | ||
: [https://github.com/gnuradio/gnuradio | : [https://github.com/gnuradio/gnuradio/blob/master/gr-fec/lib/ccsds_encoder_impl.cc ccsds_encoder_impl.cc] | ||
; Header files | ; Header files | ||
: [https://github.com/gnuradio/gnuradio | : [https://github.com/gnuradio/gnuradio/blob/master/gr-fec/lib/ccsds_encoder_impl.h ccsds_encoder_impl.h] | ||
; Public header files | ; Public header files | ||
: [https://github.com/gnuradio/gnuradio | : [https://github.com/gnuradio/gnuradio/blob/master/gr-fec/include/gnuradio/fec/ccsds_encoder.h ccsds_encoder.h] | ||
; Block definition | ; Block definition | ||
: [https://github.com/gnuradio/gnuradio | : [https://github.com/gnuradio/gnuradio/blob/master/gr-fec/grc/variable_ccsds_encoder_def_list.block.yml variable_ccsds_encoder_def_list.block.yml] | ||
Latest revision as of 14:42, 4 April 2023
CCSDS Encoding class for convolutional encoding with rate 1/2, K=7, and polynomials [109, 79].
Uses Phil Karn's (KA9Q) implementation of the CCSDS encoder for rate 1/2, K=7, and CC polynomial [109, 79]. These are non-adjustable in this encoder. For an adjustable CC encoder where we can set the rate, constraint length, and polynomial, see CC Encoder Definition.
Parameters
(R): Run-time adjustable
- Parallelism
- It seems that one can create a tensor of one or two dimensions of encoders. More info is needed on this.
- Dimension 1
- Active when parallelism > 0
- Dimension 2
- Active when parallelism > 1
- Frame bits
- When not being used in a tagged stream mode, this encoder will only process frames of the length provided here. If used in a tagged stream block, this setting becomes the maximum allowable frame size that the block may process.
- Start state
- Initialization state of the shift register.
- Streaming behaviour
- Specifies how the convolutional encoder will behave and under what conditions.
- Streaming
- This mode expects an uninterrupted flow of samples into the encoder, and the output stream is continually encoded.
- Terminated
- Mode designed for packet-based systems. This mode adds rate*(k-1) bits to the output as a way to help flush the decoder.
- Tailbiting
- Another packet-based method. Instead of adding bits onto the end of the packet, this mode will continue the code between the payloads of packets by pre-initializing the state of the new packet based on the state of the last packet for (k-1) bits.
- Truncated
- A truncated code always resets the registers to the start state between frames.
Example Flowgraph
Insert description of flowgraph here, then show a screenshot of the flowgraph and the output if there is an interesting GUI. Currently we have no standard method of uploading the actual flowgraph to the wiki or git repo, unfortunately. The plan is to have an example flowgraph showing how the block might be used, for every block, and the flowgraphs will live in the git repo.
Source Files
- C++ files
- ccsds_encoder_impl.cc
- Header files
- ccsds_encoder_impl.h
- Public header files
- ccsds_encoder.h
- Block definition
- variable_ccsds_encoder_def_list.block.yml