ramp interpolation error fix.

diff --git a/transmitter.c b/transmitter.c
index 2dc809ef8baf92ad9ff0672b4b908f045dffe50a..aba47e4d4d704f0edf7ad2f273f65fd73d933a80 100644 (file)
--- a/transmitter.c
+++ b/transmitter.c
@@ -956,6 +956,7 @@ void add_mic_sample(TRANSMITTER *tx,short mic_sample) {
   double sample;
   double mic_sample_double, ramp;
   int i,s;
+  int updown;
 
 //
 // silence TX audio if tuning, or when doing CW.
@@ -992,13 +993,13 @@ void add_mic_sample(TRANSMITTER *tx,short mic_sample) {
        if (cw_key_down > 0 ) {
          if (cw_shape < 200) cw_shape++;       // walk up the ramp
          cw_key_down--;                        // decrement key-up counter
+         updown=1;
        } else {
-         if (cw_key_up >= 0) {
-               // dig into this even if cw_key_up is already zero, to ensure
-               // that we reach the bottom of the ramp for very small pauses
-               if (cw_shape > 0) cw_shape--;   // walk down the ramp
-               if (cw_key_up > 0) cw_key_up--; // decrement key-down counter
-         }
+         // dig into this even if cw_key_up is already zero, to ensure
+         // that we reach the bottom of the ramp for very small pauses
+         if (cw_shape > 0) cw_shape--; // walk down the ramp
+         if (cw_key_up > 0) cw_key_up--; // decrement key-down counter
+         updown=0;
        }
        //
        // store the ramp value in cw_shape_buffer, but also use it for shaping the "local"
@@ -1022,10 +1023,23 @@ void add_mic_sample(TRANSMITTER *tx,short mic_sample) {
            s=0;
            if (!cw_keyer_internal || CAT_cw_is_active) s=(int) (sample * 32767.0);
            new_protocol_cw_audio_samples(s, s);
-           cw_shape_buffer192[4*tx->samples+0]=cwramp192[4*cw_shape+0];
-           cw_shape_buffer192[4*tx->samples+1]=cwramp192[4*cw_shape+1];
-           cw_shape_buffer192[4*tx->samples+2]=cwramp192[4*cw_shape+2];
-           cw_shape_buffer192[4*tx->samples+3]=cwramp192[4*cw_shape+3];
+           s=4*cw_shape;
+           i=4*tx->samples;
+           // The 192kHz-ramp is constructed such that for cw_shape==0 or cw_shape==200,
+           // the two following cases create the same shape.
+           if (updown) {
+             // climbing up...
+             cw_shape_buffer192[i+0]=cwramp192[s+0];
+             cw_shape_buffer192[i+1]=cwramp192[s+1];
+             cw_shape_buffer192[i+2]=cwramp192[s+2];
+             cw_shape_buffer192[i+3]=cwramp192[s+3];
+          } else {
+             // descending...
+             cw_shape_buffer192[i+0]=cwramp192[s+3];
+             cw_shape_buffer192[i+1]=cwramp192[s+2];
+             cw_shape_buffer192[i+2]=cwramp192[s+1];
+             cw_shape_buffer192[i+3]=cwramp192[s+0];
+          }
        }
   } else {
 //