diff --git a/local.c b/local.c
index dbda744..b967bcd 100644
--- a/local.c
+++ b/local.c
@@ -403,7 +403,7 @@ LCL_SetAbsoluteFrequency(double afreq_ppm)
 
   /* Dispatch to all handlers */
   for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
-    (ptr->handler)(&raw, &cooked, dfreq, afreq_ppm, 0.0, 0, ptr->anything);
+    (ptr->handler)(&raw, &cooked, dfreq, 0.0, 0, ptr->anything);
   }
 
   current_freq_ppm = afreq_ppm;
@@ -432,7 +432,7 @@ LCL_AccumulateDeltaFrequency(double dfreq)
 
   /* Dispatch to all handlers */
   for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
-    (ptr->handler)(&raw, &cooked, dfreq, current_freq_ppm, 0.0, 0, ptr->anything);
+    (ptr->handler)(&raw, &cooked, dfreq, 0.0, 0, ptr->anything);
   }
 
 }
@@ -455,7 +455,7 @@ LCL_AccumulateOffset(double offset)
 
   /* Dispatch to all handlers */
   for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
-    (ptr->handler)(&raw, &cooked, 0.0, current_freq_ppm, offset, 0, ptr->anything);
+    (ptr->handler)(&raw, &cooked, 0.0, offset, 0, ptr->anything);
   }
 
 }
@@ -478,7 +478,7 @@ LCL_ApplyStepOffset(double offset)
 
   /* Dispatch to all handlers */
   for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
-    (ptr->handler)(&raw, &cooked, 0.0, current_freq_ppm, offset, 1, ptr->anything);
+    (ptr->handler)(&raw, &cooked, 0.0, offset, 1, ptr->anything);
   }
 
 }
@@ -515,7 +515,7 @@ LCL_AccumulateFrequencyAndOffset(double dfreq, double doffset)
 
   /* Dispatch to all handlers */
   for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
-    (ptr->handler)(&raw, &cooked, dfreq, current_freq_ppm, doffset, 0, ptr->anything);
+    (ptr->handler)(&raw, &cooked, dfreq, doffset, 0, ptr->anything);
   }
 
 
diff --git a/local.h b/local.h
index 2b9ea82..373d246 100644
--- a/local.h
+++ b/local.h
@@ -68,10 +68,6 @@ extern void LCL_GetOffsetCorrection(struct timeval *raw, double *correction, dou
    dfreq : delta frequency relative to previous value (in terms of
    seconds gained by system clock per unit system clock time)
 
-   afreq : absolute frequency relative to uncompensated system (in
-   terms of ppm seconds gained by system clock per unit of the
-   uncalibrated system clock)
-
    doffset : delta offset applied (positive => make local system fast
    by that amount, negative => make it slow by that amount)
 
@@ -83,7 +79,7 @@ extern void LCL_GetOffsetCorrection(struct timeval *raw, double *correction, dou
 
 typedef void (*LCL_ParameterChangeHandler)
      (struct timeval *raw, struct timeval *cooked,
-      double dfreq, double afreq_ppm,
+      double dfreq,
       double doffset, int is_step_change,
       void *anything
       );
diff --git a/manual.c b/manual.c
index f3e98e1..a157632 100644
--- a/manual.c
+++ b/manual.c
@@ -74,7 +74,6 @@ static void
 slew_samples(struct timeval *raw,
              struct timeval *cooked, 
              double dfreq,
-             double afreq,
              double doffset,
              int is_step_change,
              void *not_used);
@@ -229,7 +228,6 @@ static void
 slew_samples(struct timeval *raw,
              struct timeval *cooked, 
              double dfreq,
-             double afreq,
              double doffset,
              int is_step_change,
              void *not_used)
diff --git a/ntp_sources.c b/ntp_sources.c
index eeca7ce..97453ab 100644
--- a/ntp_sources.c
+++ b/ntp_sources.c
@@ -66,7 +66,6 @@ static void
 slew_sources(struct timeval *raw,
              struct timeval *cooked,
              double dfreq,
-             double afreq,
              double doffset,
              int is_step_change,
              void *anything);
@@ -308,7 +307,6 @@ static void
 slew_sources(struct timeval *raw,
              struct timeval *cooked,
              double dfreq,
-             double afreq,
              double doffset,
              int is_step_change,
              void *anything)
diff --git a/refclock.c b/refclock.c
index f8f9d62..f4f6c0c 100644
--- a/refclock.c
+++ b/refclock.c
@@ -92,7 +92,7 @@ static LOG_FileID logfileid;
 static int valid_sample_time(RCL_Instance instance, struct timeval *tv);
 static int pps_stratum(RCL_Instance instance, struct timeval *tv);
 static void poll_timeout(void *arg);
-static void slew_samples(struct timeval *raw, struct timeval *cooked, double dfreq, double afreq,
+static void slew_samples(struct timeval *raw, struct timeval *cooked, double dfreq,
              double doffset, int is_step_change, void *anything);
 static void add_dispersion(double dispersion, void *anything);
 static void log_sample(RCL_Instance instance, struct timeval *sample_time, int filtered, int pulse, double raw_offset, double cooked_offset, double dispersion);
@@ -540,7 +540,7 @@ poll_timeout(void *arg)
 }
 
 static void
-slew_samples(struct timeval *raw, struct timeval *cooked, double dfreq, double afreq,
+slew_samples(struct timeval *raw, struct timeval *cooked, double dfreq,
              double doffset, int is_step_change, void *anything)
 {
   int i;
diff --git a/rtc_linux.c b/rtc_linux.c
index 5814111..463d8b4 100644
--- a/rtc_linux.c
+++ b/rtc_linux.c
@@ -302,20 +302,15 @@ run_regression(int new_sample,
 static void
 slew_samples
 (struct timeval *raw, struct timeval *cooked,
- double dfreq, double afreq_ppm,
+ double dfreq,
  double doffset, int is_step_change,
  void *anything)
 {
   int i;
   double elapsed;
-  double new_freq;
-  double old_freq;
   double delta_time;
   double old_seconds_fast, old_gain_rate;
 
-  new_freq = 1.0e-6 * afreq_ppm;
-  old_freq = (new_freq - dfreq) / (1.0 + dfreq);
-
   for (i=0; i<n_samples; i++) {
     UTI_DiffTimevalsToDouble(&elapsed, cooked, system_times + i);
 
@@ -330,12 +325,12 @@ slew_samples
 
   if (coefs_valid) {
     coef_seconds_fast += doffset;
-    coef_gain_rate = 1.0 - ((1.0 + new_freq) / (1.0 + old_freq)) * (1.0 - coef_gain_rate);
+    coef_gain_rate = 1.0 - (1.0 + dfreq) * (1.0 - coef_gain_rate);
   }
 
 #if 0
-  LOG(LOGS_INFO, LOGF_RtcLinux, "dfreq=%.8f doffset=%.6f new_freq=%.3f old_freq=%.3f old_fast=%.6f old_rate=%.3f new_fast=%.6f new_rate=%.3f",
-      dfreq, doffset, 1.0e6*new_freq, 1.0e6*old_freq,
+  LOG(LOGS_INFO, LOGF_RtcLinux, "dfreq=%.8f doffset=%.6f old_fast=%.6f old_rate=%.3f new_fast=%.6f new_rate=%.3f",
+      dfreq, doffset,
       old_seconds_fast, 1.0e6 * old_gain_rate,
       coef_seconds_fast, 1.0e6 * coef_gain_rate);
 #endif
diff --git a/sched.c b/sched.c
index c2d44b9..908f50b 100644
--- a/sched.c
+++ b/sched.c
@@ -120,7 +120,6 @@ static void
 handle_slew(struct timeval *raw,
             struct timeval *cooked,
             double dfreq,
-            double afreq,
             double doffset,
             int is_step_change,
             void *anything);
@@ -498,7 +497,6 @@ static void
 handle_slew(struct timeval *raw,
             struct timeval *cooked,
             double dfreq,
-            double afreq,
             double doffset,
             int is_step_change,
             void *anything)
diff --git a/sources.c b/sources.c
index f1674f2..f86f198 100644
--- a/sources.c
+++ b/sources.c
@@ -128,7 +128,7 @@ static int selected_source_index; /* Which source index is currently
 /* Forward prototype */
 
 static void
-slew_sources(struct timeval *raw, struct timeval *cooked, double dfreq, double afreq,
+slew_sources(struct timeval *raw, struct timeval *cooked, double dfreq,
              double doffset, int is_step_change, void *anything);
 static void
 add_dispersion(double dispersion, void *anything);
@@ -798,7 +798,6 @@ static void
 slew_sources(struct timeval *raw,
              struct timeval *cooked,
              double dfreq,
-             double afreq,
              double doffset,
              int is_step_change,
              void *anything)