add dl814_dj_48m, with resampling

2023-03-21 17:01:12 +08:00
parent 655bd60c2f
commit 3e93af9e9a
1645 changed files with 3417313 additions and 16 deletions
@@ -0,0 +1,30 @@
+clc; clear; close all;
+
+% parameters
+fs1 = 48e6; % sample rate 1
+fs2 = 122.88e6; % sample rate 2
+ratio_up = fs2/gcd(fs1,fs2); % upsample ratio
+ratio_dn = fs1/gcd(fs1,fs2); % downsample ratio
+interp = 8; % interpolation factor
+sumbol_num = 16;
+
+% standard pn sequence
+pn_seq = comm.PNSequence('Polynomial','x^7+x^6+1', ...
+  'InitialConditions',[zeros(1,6),1],'SamplesPerFrame',2^7-1);
+PRBS7 = pn_seq();
+PRBS7_polar = 1-2*[PRBS7;0];
+
+% square shaping 
+data_fs1 = kron(repmat(PRBS7_polar,sumbol_num,1),ones(interp,1)); 
+
+% upsample
+data_fs1_up = upsample(data_fs1,ratio_up);
+
+% anti-aliasing filter
+fir = fir1(1024,6e6/48e6/max(ratio_up,ratio_dn)*2*pi,'low');
+
+% filtering & downsample
+data_fs2 = downsample(conv(data_fs1_up,fir,'same'),ratio_dn);
+
+% quantize & export fir coefficients
+coe_gen(round(fir/max(abs(fir))*(2^15-1)),'lpf_125k.coe','filter');