add PW distortion for AVR-E, AVIR, AVL. 0% at max amplitude, 100% below set valueINSTRUMENT_6_2_11b

3 files changed, 29 insertions, 7 deletions

diff --git a/device-functions.c b/device-functions.c
index d27cf76..e5fbeea 100644
--- a/device-functions.c
+++ b/device-functions.c
@@ -2721,6 +2721,12 @@ int Set_VI_Control(int parameter,int channel,float new_ampl,int *point_found,int
 
 		(*atten_range)--;
 
+		float max1 = fabs(globals.Flash.min_ampl[channel]);
+		float max2 = fabs(globals.Flash.max_ampl[channel]);
+		if (max2 > max1) {
+			max1 = max2;
+		}
+
 		if (*atten_range == -1) {
 			// no valid attenuators
 			use_atten = 1.0;
@@ -2738,11 +2744,6 @@ int Set_VI_Control(int parameter,int channel,float new_ampl,int *point_found,int
 
 			// Limit max voltage in attenuator mode to 93% of full maximum,
 			// to avoid the region in AVPs where PW shifts at high amplitudes
-			float max1 = fabs(globals.Flash.min_ampl[channel]);
-			float max2 = fabs(globals.Flash.max_ampl[channel]);
-			if (max2 > max1) {
-				max1 = max2;
-			}
 			if ((use_ampl * use_atten) >
 			                (globals.Flash.atten_percent_max_ampl[channel] * max1)) {
 				continue;
@@ -2753,7 +2754,25 @@ int Set_VI_Control(int parameter,int channel,float new_ampl,int *point_found,int
 			/* apply pw ampl/pol tweaks */
 			if (parameter == pwl_pw_values) {
 				// tweak pw shifts
-				tweaked_use_ampl = use_ampl + globals.Flash.pw_range_pol_tweaks[channel][range_i][pw_polarity];
+				float dist_frac = 1.0; // use same tweaking for all amplitudes by default
+
+				if (fabs(globals.Flash.distort_fully_below_ampl[channel]) > 0.0) {
+					// if distort_fully_below_ampl is specified (typically for AVR-E, AVIR, etc),
+					// distort zero at max ampl, and fully below specified ampl
+					dist_frac = 	(max1 - fabs(globals.ChannelState[channel].amplitude)) /
+							(max1 - fabs(globals.Flash.distort_fully_below_ampl[channel]));
+					if (dist_frac > 1.0) {
+						dist_frac = 1.0;
+					}
+
+					if (dist_frac < 0.0) {
+						dist_frac = 0.0;
+					}
+				}
+
+				float correction = dist_frac * globals.Flash.pw_range_pol_tweaks[channel][range_i][pw_polarity];
+				tweaked_use_ampl = use_ampl + correction;
+
 			} else if (parameter == pwl_ampl_values) {
 				// compensate for attenuators
 				tweaked_use_ampl = use_ampl * use_atten;
diff --git a/flash.c b/flash.c
index 431a7db..8a0926e 100644
--- a/flash.c
+++ b/flash.c
@@ -723,6 +723,8 @@ static void initFlashValues(FlashStruct *mem)
 		mem->max_duty_mid2[i]=0.0;
 		mem->duty_ampl_mid2[i]=0.0;
 
+		mem->distort_fully_below_ampl[i]=0.0;
+
 		mem->min_slew[i]=90e6;
 		mem->max_slew[i]=210e6;
 		mem->max_high_rl_duty[i]=80.0;
diff --git a/globals.h b/globals.h
index 58b6fb7..234b505 100644
--- a/globals.h
+++ b/globals.h
@@ -614,7 +614,8 @@ typedef struct {
 	float max_duty_mid2[max_channels];		/* addr 8094 */
 	float duty_ampl_mid2[max_channels];          	/* addr 8102 */
 
-	char spare_char[288]; 				/* 8110 */
+	float distort_fully_below_ampl[max_channels];	/* addr 8110 - used with pulse_width_pol_tweak, see S/N 13453 */
+	char spare_char[280]; 				/* 8118 */
 
 	float current_limit_pulse_mode[max_channels];	/* 8398 */
 	float current_limit_dc_mode[max_channels];	/* 8406 */