From: baobrien <baobrien@01035d8c-6547-0410-b346-abe4f91aad63>
Date: Wed, 11 Mar 2015 22:06:01 +0000 (+0000)
Subject: reverting changes to iir_duc.m
X-Git-Url: http://git.whiteaudio.com/gitweb/?a=commitdiff_plain;h=cd5106706cbe4bc3298c73088e05bef417f58a38;p=freetel-svn-tracking.git

reverting changes to iir_duc.m


git-svn-id: https://svn.code.sf.net/p/freetel/code@2068 01035d8c-6547-0410-b346-abe4f91aad63
---

diff --git a/codec2-dev/octave/dacres.m b/codec2-dev/octave/dacres.m
index 34f7ee9d..a57ea309 100644
--- a/codec2-dev/octave/dacres.m
+++ b/codec2-dev/octave/dacres.m
@@ -19,17 +19,15 @@ pcicfb = fir1(20,.5); %Interpolation LPF Fir
 s1fir = filter(ciccb,1,pcicfb); %Combine compensation and LPF
 
 t = (1:fs/2);
-scpin = .1*sin(t*pi*2*(3000/8000))*i;       % initial complex input
+scpin = e.^(i*(t*pi*2*(3000/8000)));       % initial complex input
 scpin(1) = 1+i;
 
 intstage1 = zeros(1,2*length(scpin));   %First stage of interpolation, 2x
 intstage1(1:2:2*length(scpin))=scpin;
-%scpin = filter(s1fir,1,scpin);
 
 scireal = int32(filter(s1fir,1,real(intstage1))*csf);       %separate input into real and imiginary and apply pre-distortion
 sciimag = int32(filter(s1fir,1,imag(intstage1))*csf);       % also convert to integer. CIC integrator needs integer to work properly
 
-
 %Apply 3 stage comb to real
 fdin = scireal;
 combout1=0;
@@ -74,6 +72,7 @@ end
 scoreal=single(fdnext/(2**20));
 
 fdin=sciimag;
+
 %Apply 3 stage comb to imag
 combout1=0;
 combout2=0;
@@ -134,6 +133,10 @@ sducinterp = zeros(1,length(sduceq)*M);    %interpolate by zero-stuffing
 sducinterp(1:M:length(sduceq)*M) = sduceq;
 sdac = filter(1,[1 b1x beta1],sducinterp); %select wanted signal
 
+sdac = sdac + median(sdac);  %Center above zero
+sdac = sdac / max(sdac);     %normalize
+sdac = int32(sdac*2000);     %integerize
+
 figure(1)
 subplot(211)
 plot(20*log10(abs(fft(sducin)/fi)))
diff --git a/codec2-dev/stm32/src/iir_duc.c b/codec2-dev/stm32/src/iir_duc.c
index 4c69d0dc..25f3944a 100644
--- a/codec2-dev/stm32/src/iir_duc.c
+++ b/codec2-dev/stm32/src/iir_duc.c
@@ -47,7 +47,7 @@
 
 //IIR and FIR filter states. Global for go fast.
 float f_1,f_2,f;
-int   n1_1,n1_2,n1,n2_1,n2_2,n2;
+int   n_1,n_2,n;
 
 /*
    Upconvert and bandpass filter a chunk of spectrum from Fs/M to Fs. We're going for 700khz here.
@@ -64,23 +64,17 @@ void iir_upconv(float modin[], unsigned short dac_out[]){
         f_2 = f_1;
         f_1 = modin[i];                                             //Scale fir output and convert to fixed.
         m = (int)((f/(IN_SCALE))*DAC_SCALE_2);                      //Scale fir output and convert to fixed
-        n1 = m + ((B1SMUL*n1_1)>>B1SHFT) - ((B1MUL*n1_2)>>B1SHFT);   //Apply one cycle of IIR. This feeds the fir-ed sample into the output filter
-        n1_2 = n1_1;
-        n1_1 = n1;
-	n2 = n1 + ((B1SMUL*n2_1)>>B1SHFT) - ((B1MUL*n2_2)>>B1SHFT);
-	n2_2 = n2_1;
-	n2_1 = n2;
-        dac_out[k]=(unsigned short)(n2+DAC_SCALE_2);
+        n = m + ((B1SMUL*n_1)>>B1SHFT) - ((B1MUL*n_2)>>B1SHFT);   //Apply one cycle of IIR. This feeds the fir-ed sample into the output filter
+        n_2 = n_1;
+        n_1 = n;
+        dac_out[k]=(unsigned short)(n+DAC_SCALE_2);
         k++;
         //now do the rest of the filtering. Because we're zero-stuffing we can neglect the sample from the fir filter.
         for(j=1;j<DUC_M;j++,k++){
             n = ((B1SMUL*n_1)>>B1SHFT) - ((B1MUL*n_2)>>B1SHFT);
             n_2 = n_1;
             n_1 = n;
-	    n2 = n1 + ((B1SMUL*n2_1)>>B1SHFT) - ((B1MUL*n2_2)>>B1SHFT);
-	    n2_2 = n2_1;
-	    n2_1 = n2;
-            dac_out[k]=(unsigned short)((n2)+DAC_SCALE_2);
+            dac_out[k]=(unsigned short)((n)+DAC_SCALE_2);
         }
     }
 }