Default Header Format Obj.: Difference between revisions
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Default header formatter for PDU formatting. Used to handle the default packet header. | |||
See the parent class header_format_base for details of how these classes operate. | |||
The default header created in this base class consists of an access code and the packet length. The length is encoded as a 16-bit value repeated twice: | |||
| access code | hdr | payload | | |||
Where the access code is <= 64 bits and hdr is: | |||
| 0 -- 15 | 16 -- 31 | | |||
| pkt len | pkt len | | |||
The access code and header are formatted for network byte order. | |||
This header generator does not calculate or append a CRC to the packet. Use the CRC32 Async block for that before adding the header. The header's length will then measure the payload plus the CRC length (4 bytes for a CRC32). | |||
The default header parser produces a PMT dictionary that contains the following keys. All formatter blocks MUST produce these two values in any dictionary. | |||
See [https://www.gnuradio.org/doc/doxygen/classgr_1_1digital_1_1header__format__default.html] for more info. | |||
== Parameters == | == Parameters == | ||
; Access Code | |||
: An access code that is used to find and synchronize the start of a packet. Used in the parser and in other blocks like a corr_est block that helps trigger the receiver. Can be up to 64-bits long. | |||
; | ; Threshold | ||
: | : How many bits can be wrong in the access code and still count as correct. | ||
; | ; Payload Bits per Symbol | ||
: | : The number of bits per symbol used in the payload's modulator. | ||
== Example Flowgraph == | == Example Flowgraph == | ||
[[File:Pkt_3_fg.png|800px]] | |||
== Source Files == | == Source Files == | ||
Latest revision as of 13:53, 12 November 2021
Default header formatter for PDU formatting. Used to handle the default packet header.
See the parent class header_format_base for details of how these classes operate.
The default header created in this base class consists of an access code and the packet length. The length is encoded as a 16-bit value repeated twice:
| access code | hdr | payload |
Where the access code is <= 64 bits and hdr is:
| 0 -- 15 | 16 -- 31 | | pkt len | pkt len |
The access code and header are formatted for network byte order.
This header generator does not calculate or append a CRC to the packet. Use the CRC32 Async block for that before adding the header. The header's length will then measure the payload plus the CRC length (4 bytes for a CRC32).
The default header parser produces a PMT dictionary that contains the following keys. All formatter blocks MUST produce these two values in any dictionary.
See [1] for more info.
Parameters
- Access Code
- An access code that is used to find and synchronize the start of a packet. Used in the parser and in other blocks like a corr_est block that helps trigger the receiver. Can be up to 64-bits long.
- Threshold
- How many bits can be wrong in the access code and still count as correct.
- Payload Bits per Symbol
- The number of bits per symbol used in the payload's modulator.
Example Flowgraph
Source Files
- C++ files
- TODO
- Header files
- TODO
- Public header files
- TODO
- Block definition
- TODO