From e484814c0ab0f9765a208ce6c1e3ba9cfe51ab72 Mon Sep 17 00:00:00 2001
From: Andreas Eversberg <jolly@eversberg.eu>
Date: Wed, 3 Aug 2016 12:02:15 +0200
Subject: [PATCH] C-Netz: Add hack to increase voice deviation for some newer
 phone

---
 src/cnetz/dsp.c  | 17 ++++++++++++++++-
 src/cnetz/main.c | 11 ++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/cnetz/dsp.c b/src/cnetz/dsp.c
index cab2030..e2be69c 100644
--- a/src/cnetz/dsp.c
+++ b/src/cnetz/dsp.c
@@ -33,6 +33,8 @@
 #include "telegramm.h"
 #include "dsp.h"
 
+extern int voice_deviation;
+
 /* test function to mirror received audio from ratio back to radio */
 //#define TEST_SCRAMBLE
 /* test the audio quality after cascading two scramblers (TEST_SCRAMBLE must be defined) */
@@ -721,6 +723,18 @@ again:
 			/* pre-emphasis is only used when scrambler is off, see FTZ 171 TR 60 Clause 4 */
 			if (cnetz->pre_emphasis && !cnetz->scrambler)
 				pre_emphasis(&cnetz->estate, speech_buffer, speech_length);
+			/* change level */
+			if (voice_deviation != 1) {
+				int sample, j;
+				for (j = 0; j < speech_length; j++) {
+					sample = speech_buffer[j] * voice_deviation;
+					if (sample > 32767)
+						sample = 32767;
+					if (sample < -32768)
+						sample = -32768;
+					speech_buffer[j] = sample;
+				}
+			}
 			speech_pos = 0;
 		}
 		/* copy speech as long as we have something left in buffer */
@@ -791,7 +805,8 @@ void unshrink_speech(cnetz_t *cnetz, int16_t *speech_buffer, int count)
 	y_last = cnetz->offset_y_last;
 	factor = cnetz->offset_factor;
 	for (i = 0; i < count; i++) {
-		x = (double)speech_buffer[i];
+		/* change level */
+		x = (double)speech_buffer[i] / voice_deviation;
 		/* high-pass to remove low level frequencies, caused by level jump between audio chunks */
 		y = factor * (y_last + x - x_last);
 		x_last = x;
diff --git a/src/cnetz/main.c b/src/cnetz/main.c
index d6fed8e..fa64476 100644
--- a/src/cnetz/main.c
+++ b/src/cnetz/main.c
@@ -49,6 +49,7 @@ const char *flip_polarity = "auto";
 double noise = 0.0;
 int ms_power = 0; /* 0..3 */
 int auth = 0;
+int voice_deviation = 1;
 
 void print_help(const char *arg0)
 {
@@ -79,6 +80,9 @@ void print_help(const char *arg0)
 	printf("        Enable authentication on the base station. Since we cannot\n");
 	printf("	authenticate, because we don't know the secret key and the algorithm,\n");
 	printf("	we just accept any card. With this we get the vendor IDs of the phone.\n");
+	printf(" -V --voice-deviation\n");
+	printf("	For some unknown reason, Siemens C5 use double deviation for voice.\n");
+	printf("	This option raises audio level on TX and lowers on RX.\n");
 	printf("\nstation-id: Give 7 digit station-id, you don't need to enter it for every\n");
 	printf("        start of this program.\n");
 	printf("\nPress 'i' key for dumping currently attached subscribers.\n");
@@ -98,10 +102,11 @@ static int handle_options(int argc, char **argv)
 		{"noise", 1, 0, 'N'},
 		{"ms-power", 1, 0, 'P'},
 		{"authentication", 0, 0, 'A'},
+		{"voice-deviation", 0, 0, 'V'},
 		{0, 0, 0, 0}
 	};
 
-	set_options_common("t:MS:F:N:P:A", long_options_special);
+	set_options_common("t:MS:F:N:P:AV", long_options_special);
 
 	while (1) {
 		int option_index = 0, c;
@@ -169,6 +174,10 @@ static int handle_options(int argc, char **argv)
 			auth = 1;
 			skip_args += 1;
 			break;
+		case 'V':
+			voice_deviation = 2;
+			skip_args += 1;
+			break;
 		default:
 			opt_switch_common(c, argv[0], &skip_args);
 		}