diff --git a/src/ps/aps.rs b/src/ps/aps.rs
index c32af7f..e409260 100644
--- a/src/ps/aps.rs
+++ b/src/ps/aps.rs
@@ -136,7 +136,9 @@ impl AvPowerSpectra {
                 // });
 
                 // Option 2: broadcasting with an unwrap.
-                azip!((c in &mut Cpsnew, f in fw_pwr.broadcast(dim).unwrap()) {
+                let dview_fw = fw_pwr.slice(s![..,NewAxis, NewAxis]);
+                azip!((c in &mut Cpsnew, f in dview_fw.broadcast(dim).expect("BUG: Cannot broadcast")) {
+                    // Scale with frequency weighting
                     *c = Cflt::new(c.re * f, c.im * f);
                 });
             }
@@ -300,7 +302,8 @@ impl AvPowerSpectra {
             let res = res.clone();
             return res.to_pyarray_bound(py);
         }
-        panic!("No data!");
+        let res: Bound<'py, PyArray3<Cflt>> = PyArray3::zeros_bound(py, [0, 0, 0], true);
+        res
     }
 }
 #[cfg(test)]
@@ -333,7 +336,7 @@ mod test {
                 .fs(1.)
                 .overlap(overlap.clone())
                 .build()
-                .unwrap();
+                .expect("BUG: Settings cannot be build.");
 
             assert_eq!(settings.get_overlap_keep(), *expected);
         }
@@ -352,12 +355,12 @@ mod test {
             .overlap(Overlap::NoOverlap {})
             .mode(ApsMode::ExponentialWeighting { tau })
             .build()
-            .unwrap();
+            .expect("Settings cannot be empty");
         let overlap_keep = settings.get_overlap_keep();
         let mut aps = AvPowerSpectra::new(settings);
         assert_eq!(aps.overlap_keep, 0);
 
-        let distr = Normal::new(1.0, 1.0).unwrap();
+        let distr = Normal::new(1.0, 1.0).expect("Distribution cannot be built");
         let timedata_some = Dmat::random((nfft, 1), distr);
         let timedata_zeros = Dmat::zeros((nfft, 1));
 
diff --git a/src/ps/fft.rs b/src/ps/fft.rs
index 4433095..863afc6 100644
--- a/src/ps/fft.rs
+++ b/src/ps/fft.rs
@@ -1,7 +1,7 @@
 //! Compute forward single sided amplitude spectra
 use crate::config::*;
 use realfft::{RealFftPlanner, RealToComplex};
-use std::sync::Arc;
+use std::{fmt::Debug, sync::Arc};
 
 #[derive(Clone)]
 pub struct FFT {
diff --git a/src/ps/freqweighting.rs b/src/ps/freqweighting.rs
index 1d32cc0..5882604 100644
--- a/src/ps/freqweighting.rs
+++ b/src/ps/freqweighting.rs
@@ -28,6 +28,9 @@ impl FreqWeighting {
     fn __str__(&self) -> String {
         format!("{self}-weighting")
     }
+    fn letter(&self) -> String {
+        format!("{self}")
+    }
     #[staticmethod]
     #[pyo3(name = "default")]
     fn default_py() -> Self {
diff --git a/src/ps/ps.rs b/src/ps/ps.rs
index 8ae54ab..6b0847d 100644
--- a/src/ps/ps.rs
+++ b/src/ps/ps.rs
@@ -141,13 +141,15 @@ impl PowerSpectra {
     /// Compute FFTs of input channel data. Stores the scaled FFT data in
     /// self.freqdata.
     fn compute_ffts(&mut self, timedata: ArrayView2<Flt>) -> ArrayView2<Cflt> {
+        assert!(timedata.nrows() > 0);
         let (n, nch) = timedata.dim();
         let nfft = self.nfft();
         assert!(n == nfft);
 
         // Make sure enough fft engines are available
         while nch > self.ffts.len() {
-            self.ffts.push(self.ffts.last().unwrap().clone());
+            self.ffts
+                .push(self.ffts.last().expect("FFT's should not be empty").clone());
             self.freqdata
                 .push_column(Ccol::from_vec(vec![Cflt::new(0., 0.); nfft / 2 + 1]).view())
                 .unwrap();