bpsk_tx_func.m

function txdata = bpsk_tx_func(msgStr)
%% train sequence
seq_sync=tx_gen_m_seq([1 0 0 0 0 0 1]); 
% Set up constellation diagram with pi/3 = 0
% and -pi/3 = 1 as modulation values
sync_symbols=tx_modulate(seq_sync, 'BPSK');

%% Zeropadding message if number of char < 60
% Since the message is broken into packets of 60 characters (3 for control
% and 578 usable characters) we need to zero pad the end of a message with
% meaningless characters so the packet can be sent.
for k = length(msgStr)+1 :60
    msgStr = [msgStr, char(0)];
end

%% string to bits
mst_bits=str_to_bits(msgStr);

%% crc32
ret=crc32(mst_bits);
inf_bits=[mst_bits ret.'];

%% scramble
scramble_int=[1,1,0,1,1,0,0];
sym_bits=scramble(scramble_int, inf_bits);

%% modulate
mod_symbols=tx_modulate(sym_bits, 'BPSK');

%% insert pilot
data_symbols=insert_pilot(mod_symbols);
trans_symbols=[sync_symbols data_symbols];

%% srrc
fir=rcosdesign(1,128,4);
tx_frame=upfirdn(trans_symbols,fir,4);
tx_frame=[tx_frame, zeros(1,2e3)];
txdata = tx_frame.';

%% display
% plot(real(tx_frame));
% hold on
% plot(imag(tx_frame));

end