Hi, I have created a packet header that subclasses gr::digital::packet_header_default and so far so good.
In trying to understand the base class behaviour, I created a simple header packet generation GRC project that multiplexes a header with a payload. The header_formatter is defined as digital.packet_header_default(32,legnth_tag_key) where length_tag_key is set to “packet_len”; this is the same as many examples, obviously. The header packet generator works fine with this, generating a 32 byte header with 1 bit of header data per byte. This makes sense since I left the default bits_per_byte in the header_formatter, which implies a BPSK modulator is used for the header. However, if I change the header_formatter to digital.packet_header_default(32,legnth_tag_key,num_tag_key,header_mod.bits_per_symbol()) where num_tag_key is “packet_num” and header_mod is defined as digital.constellation_qpsk(), which means now 2 header bits per byte are encoded, the header generator still outputs 32 bytes and a packet_len = 32. Shouldn’t 16 bytes be output and packet_len = 16? Accounting for the bits per symbol would make sense a) because that is consistent with the packet_header_default constructor bits_per_byte argument and b) it would be consistent with the behaviour of other blocks, such as Repack Bits, that are commonly used with packet blocks. Anyone have an explanation? Perhaps I am not following GNU Radio philosophy in this approach? BTW, in my packet header class I simply override the packet_header_default::header_len() to return the right number of bytes. That seems right to me :-) Thanks! steven Steven Knudsen, Ph.D., P.Eng. www. techconficio.ca <http://techconficio.ca/> www.linkedin.com/in/knudstevenknudsen <http://www.linkedin.com/in/knudstevenknudsen> All the wires are cut, my friends Live beyond the severed ends. Louis MacNeice
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
