Additive Scrambler: Difference between revisions
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[[Category:Block Docs]] | [[Category:Block Docs]] | ||
Scramble an input stream using | Scramble an input stream using a Linear Feedback Shift Register (LFSR). | ||
This block scrambles up to 8 bits per byte of the input data stream, starting at the LSB. | This block scrambles up to 8 bits per byte of the input data stream, starting at the LSB. | ||
| Line 7: | Line 7: | ||
Alternatively, the LFSR can be reset using a reset tag to scramble variable length vectors. However, it cannot be reset between bytes. | Alternatively, the LFSR can be reset using a reset tag to scramble variable length vectors. However, it cannot be reset between bytes. | ||
For details on configuring the LFSR, see gr::digital::lfsr. | For details on configuring the LFSR, see [https://www.gnuradio.org/doc/doxygen/classgr_1_1digital_1_1lfsr.html gr::digital::lfsr]. | ||
== 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> | ||
; | ; Mask : Polynomial mask for LFSR | ||
; | ; Seed : Initial shift register contents | ||
: Initial shift register contents | ; Length : Shift register length | ||
; | ; Count: Number of bytes after which shift register is reset, 0=never | ||
: Shift register length | ; Bits per byte : Number of bits per byte | ||
; | ; Reset tag key : When a tag with this key is detected, the shift register is reset (when this is set, count is ignored!) | ||
: Number of bytes after which shift register is reset, 0=never | |||
; | |||
: Number of bits per byte | |||
; | |||
: When a tag with this key is detected, the shift register is reset (when this is set, count is ignored!) | |||
== Example Flowgraph == | == Example Flowgraph == | ||
Latest revision as of 16:00, 27 December 2019
Scramble an input stream using a Linear Feedback Shift Register (LFSR).
This block scrambles up to 8 bits per byte of the input data stream, starting at the LSB. The scrambler works by XORing the incoming bit stream by the output of the LFSR. Optionally, after bits have been processed, the shift register is reset to the value. This allows processing fixed length vectors of samples.
Alternatively, the LFSR can be reset using a reset tag to scramble variable length vectors. However, it cannot be reset between bytes.
For details on configuring the LFSR, see gr::digital::lfsr.
Parameters
(R): Run-time adjustable
- Mask
- Polynomial mask for LFSR
- Seed
- Initial shift register contents
- Length
- Shift register length
- Count
- Number of bytes after which shift register is reset, 0=never
- Bits per byte
- Number of bits per byte
- Reset tag key
- When a tag with this key is detected, the shift register is reset (when this is set, count is ignored!)
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
- TODO
- Header files
- TODO
- Public header files
- TODO
- Block definition
- TODO