diff --git a/src/ofdm.c b/src/ofdm.c
index ba22f3f9..8d7a6dfc 100644
--- a/src/ofdm.c
+++ b/src/ofdm.c
@@ -192,6 +192,8 @@ struct OFDM *ofdm_create(const struct OFDM_CONFIG *config) {
     ofdm->codename = "HRA_112_112";
     ofdm->amp_est_mode = 0;
     ofdm->tx_bpf_en = true;
+    ofdm->tx_bpf_proto = filtP650S900;
+    ofdm->tx_bpf_proto_n = sizeof(filtP650S900) / sizeof(float);
     ofdm->rx_bpf_en = false;
     ofdm->amp_scale = 245E3;
     ofdm->clip_gain1 = 2.0;
@@ -226,6 +228,8 @@ struct OFDM *ofdm_create(const struct OFDM_CONFIG *config) {
     ofdm->codename = config->codename;
     ofdm->amp_est_mode = config->amp_est_mode;
     ofdm->tx_bpf_en = config->tx_bpf_en;
+    ofdm->tx_bpf_proto = config->tx_bpf_proto;
+    ofdm->tx_bpf_proto_n = config->tx_bpf_proto_n;
     ofdm->rx_bpf_en = config->rx_bpf_en;
     ofdm->foff_limiter = config->foff_limiter;
     ofdm->amp_scale = config->amp_scale;
@@ -275,6 +279,8 @@ struct OFDM *ofdm_create(const struct OFDM_CONFIG *config) {
   ofdm->config.codename = ofdm->codename;
   ofdm->config.amp_est_mode = ofdm->amp_est_mode;
   ofdm->config.tx_bpf_en = ofdm->tx_bpf_en;
+  ofdm->config.tx_bpf_proto = ofdm->tx_bpf_proto;
+  ofdm->config.tx_bpf_proto_n = ofdm->tx_bpf_proto_n;
   ofdm->config.rx_bpf_en = ofdm->rx_bpf_en;
   ofdm->config.foff_limiter = ofdm->foff_limiter;
   ofdm->config.amp_scale = ofdm->amp_scale;
@@ -539,36 +545,19 @@ struct OFDM *ofdm_create(const struct OFDM_CONFIG *config) {
 static void allocate_tx_bpf(struct OFDM *ofdm) {
   ofdm->tx_bpf = MALLOC(sizeof(struct quisk_cfFilter));
   assert(ofdm->tx_bpf != NULL);
+  assert(ofdm->tx_bpf_proto != NULL);
+  assert(ofdm->tx_bpf_proto_n != 0);
 
-  /* Transmit bandpass filter; complex coefficients, center frequency */
-
-  if (!strcmp(ofdm->mode, "700D")) {
-    quisk_filt_cfInit(ofdm->tx_bpf, filtP650S900,
-                      sizeof(filtP650S900) / sizeof(float));
-    quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs);
-  } else if (!strcmp(ofdm->mode, "700E") || !strcmp(ofdm->mode, "2020") ||
-             !strcmp(ofdm->mode, "datac1")) {
-    quisk_filt_cfInit(ofdm->tx_bpf, filtP900S1100,
-                      sizeof(filtP900S1100) / sizeof(float));
-    quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs);
-  } else if (!strcmp(ofdm->mode, "2020B")) {
-    quisk_filt_cfInit(ofdm->tx_bpf, filtP1100S1300,
-                      sizeof(filtP1100S1300) / sizeof(float));
-    quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs);
-  } else if (!strcmp(ofdm->mode, "datac0") || !strcmp(ofdm->mode, "datac3")) {
-    quisk_filt_cfInit(ofdm->tx_bpf, filtP400S600,
-                      sizeof(filtP400S600) / sizeof(float));
-    quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs);
-  } else if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13") ||
-             !strcmp(ofdm->mode, "datac14")) {
-    quisk_filt_cfInit(ofdm->tx_bpf, filtP200S400,
-                      sizeof(filtP200S400) / sizeof(float));
-    // centre the filter on the mean carrier freq, allows a narrower filter to
-    // be used
-    float tx_centre = find_carrier_centre(ofdm);
-    quisk_cfTune(ofdm->tx_bpf, tx_centre / ofdm->fs);
-  } else
-    assert(0);
+  quisk_filt_cfInit(ofdm->tx_bpf, ofdm->tx_bpf_proto, ofdm->tx_bpf_proto_n);
+  float tx_centre = ofdm->tx_centre;
+  if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13") ||
+      !strcmp(ofdm->mode, "datac14")) {
+    // Centre the filter on the mean carrier freq, allows a narrower
+    // filter to be used. Only really useful for very narrow, Nc odd
+    // waveforms. TODO: make this feature config controlled
+    tx_centre = find_carrier_centre(ofdm);
+  }
+  quisk_cfTune(ofdm->tx_bpf, tx_centre / ofdm->fs);
 }
 
 static void deallocate_tx_bpf(struct OFDM *ofdm) {
@@ -589,7 +578,9 @@ static void allocate_rx_bpf(struct OFDM *ofdm) {
   ofdm->rx_bpf = MALLOC(sizeof(struct quisk_cfFilter));
   assert(ofdm->rx_bpf != NULL);
 
-  /* Receive bandpass filter; complex coefficients, center frequency */
+  /* Receive bandpass filter; complex coefficients, center frequency, only
+     really needed for very low SNR waveforms. TODO: make this config
+     controlled. */
 
   if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13") ||
       !strcmp(ofdm->mode, "datac14")) {
diff --git a/src/ofdm_internal.h b/src/ofdm_internal.h
index 8007934f..3cb91308 100644
--- a/src/ofdm_internal.h
+++ b/src/ofdm_internal.h
@@ -94,15 +94,17 @@ struct OFDM_CONFIG {
   char *codename;      /* name of LDPC code used with this mode */
   uint8_t tx_uw[MAX_UW_BITS]; /* user defined unique word */
   int amp_est_mode;
-  bool tx_bpf_en;    /* default tx (mod) hilbert clipper BPF enable */
-  bool rx_bpf_en;    /* default rx (demod) input BPF enable */
-  bool foff_limiter; /* tames freq offset updates in low SNR */
-  float amp_scale;   /* used to scale Tx waveform to approx FREEDV_PEAK with
-                        clipper off */
-  float clip_gain1;  /* gain we apply to Tx signal before clipping to control
-                        PAPR*/
-  float clip_gain2;  /* gain we apply to Tx signal after clipping and BBF to
-                        control peak level */
+  bool tx_bpf_en;      /* default tx (mod) hilbert clipper BPF enable */
+  bool rx_bpf_en;      /* default rx (demod) input BPF enable */
+  float *tx_bpf_proto; /* low pass prototype for complex BPF */
+  int tx_bpf_proto_n;  /* number of taps in low pass prototype */
+  bool foff_limiter;   /* tames freq offset updates in low SNR */
+  float amp_scale;     /* used to scale Tx waveform to approx FREEDV_PEAK with
+                          clipper off */
+  float clip_gain1;    /* gain we apply to Tx signal before clipping to control
+                          PAPR*/
+  float clip_gain2;    /* gain we apply to Tx signal after clipping and BBF to
+                          control peak level */
   bool clip_en;
   char mode[16]; /* OFDM mode in string form */
   char *data_mode;
@@ -156,6 +158,7 @@ struct OFDM {
   int packetsperburst; /* for OFDM data modes, how many packets before we reset
                           state machine */
   int amp_est_mode;    /* amplitude estimtor algorithm */
+  int tx_bpf_proto_n;  /* number of taps in low pass prototype */
   float amp_scale;
   float clip_gain1;
   float clip_gain2;
@@ -220,6 +223,7 @@ struct OFDM {
   float coarse_foff_est_hz;
   float timing_norm;
   float mean_amp;
+  float *tx_bpf_proto;
 
   // Integer
   int clock_offset_counter;
diff --git a/src/ofdm_mode.c b/src/ofdm_mode.c
index df0b4f5e..b6c8c369 100644
--- a/src/ofdm_mode.c
+++ b/src/ofdm_mode.c
@@ -46,6 +46,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
   config->clip_gain2 = 0.8;
   config->clip_en = true;
   config->tx_bpf_en = true;
+  config->tx_bpf_proto = filtP650S900;
+  config->tx_bpf_proto_n = sizeof(filtP650S900) / sizeof(float);
   config->rx_bpf_en = false;
   config->amp_scale = 245E3;
   config->foff_limiter = false;
@@ -69,6 +71,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->amp_scale = 155E3;
     config->clip_gain1 = 3;
     config->clip_gain2 = 0.8;
+    config->tx_bpf_proto = filtP900S1100;
+    config->tx_bpf_proto_n = sizeof(filtP900S1100) / sizeof(float);
   } else if ((strcmp(mode, "2020") == 0)) {
     config->ts = 0.0205;
     config->nc = 31;
@@ -76,6 +80,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->amp_scale = 167E3;
     config->clip_gain1 = 2.5;
     config->clip_gain2 = 0.8;
+    config->tx_bpf_proto = filtP900S1100;
+    config->tx_bpf_proto_n = sizeof(filtP900S1100) / sizeof(float);
   } else if (strcmp(mode, "2020B") == 0) {
     config->ts = 0.014;
     config->tcp = 0.004;
@@ -92,6 +98,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->state_machine = "voice2";
     config->ftwindowwidth = 64;
     config->foff_limiter = true;
+    config->tx_bpf_proto = filtP1100S1300;
+    config->tx_bpf_proto_n = sizeof(filtP1100S1300) / sizeof(float);
   } else if (strcmp(mode, "qam16") == 0) {
     /* not in use yet */
     config->ns = 5;
@@ -109,6 +117,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->tx_bpf_en = false;
     config->clip_en = false;
     config->data_mode = "streaming";
+    config->tx_bpf_proto = NULL;
+    config->tx_bpf_proto_n = 0;
   } else if (strcmp(mode, "datac0") == 0) {
     config->ns = 5;
     config->np = 4;
@@ -130,6 +140,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->amp_scale = 300E3;
     config->clip_gain1 = 2.2;
     config->clip_gain2 = 0.85;
+    config->tx_bpf_proto = filtP400S600;
+    config->tx_bpf_proto_n = sizeof(filtP400S600) / sizeof(float);
   } else if (strcmp(mode, "datac1") == 0) {
     config->ns = 5;
     config->np = 38;
@@ -152,6 +164,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->amp_scale = 145E3;
     config->clip_gain1 = 2.7;
     config->clip_gain2 = 0.8;
+    config->tx_bpf_proto = filtP900S1100;
+    config->tx_bpf_proto_n = sizeof(filtP900S1100) / sizeof(float);
   } else if (strcmp(mode, "datac3") == 0) {
     config->ns = 5;
     config->np = 29;
@@ -176,6 +190,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->amp_scale = 300E3;
     config->clip_gain1 = 2.2;
     config->clip_gain2 = 0.8;
+    config->tx_bpf_proto = filtP400S600;
+    config->tx_bpf_proto_n = sizeof(filtP400S600) / sizeof(float);
   } else if (strcmp(mode, "datac4") == 0) {
     config->ns = 5;
     config->np = 47;
@@ -201,6 +217,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->clip_gain1 = 1.2;
     config->clip_gain2 = 1.0;
     config->rx_bpf_en = true;
+    config->tx_bpf_proto = filtP200S400;
+    config->tx_bpf_proto_n = sizeof(filtP200S400) / sizeof(float);
   } else if (strcmp(mode, "datac13") == 0) {
     config->ns = 5;
     config->np = 18;
@@ -226,6 +244,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->clip_gain1 = 1.2;
     config->clip_gain2 = 1.0;
     config->rx_bpf_en = true;
+    config->tx_bpf_proto = filtP200S400;
+    config->tx_bpf_proto_n = sizeof(filtP200S400) / sizeof(float);
   } else if (strcmp(mode, "datac14") == 0) {
     config->ns = 5;
     config->np = 4;
@@ -251,6 +271,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     config->clip_gain1 = 2.0;
     config->clip_gain2 = 1.0;
     config->rx_bpf_en = true;
+    config->tx_bpf_proto = filtP200S400;
+    config->tx_bpf_proto_n = sizeof(filtP200S400) / sizeof(float);
   } else {
     assert(0);
   }