diff --git a/nemo/collections/tts/torch/data.py b/nemo/collections/tts/torch/data.py
index 248fd355fbbb..a929c0b5a8e2 100644
--- a/nemo/collections/tts/torch/data.py
+++ b/nemo/collections/tts/torch/data.py
@@ -52,6 +52,16 @@
 from nemo.utils import logging
 
 
+EPSILON = 1e-9
+WINDOW_FN_SUPPORTED = {
+    'hann': torch.hann_window,
+    'hamming': torch.hamming_window,
+    'blackman': torch.blackman_window,
+    'bartlett': torch.bartlett_window,
+    'none': None,
+}
+
+
 class TTSDataset(Dataset):
     def __init__(
         self,
@@ -230,13 +240,13 @@ def __init__(
             dtype=torch.float,
         ).unsqueeze(0)
 
-        window_fn = {
-            'hann': torch.hann_window,
-            'hamming': torch.hamming_window,
-            'blackman': torch.blackman_window,
-            'bartlett': torch.bartlett_window,
-            'none': None,
-        }.get(self.window, None)
+        try:
+            window_fn = WINDOW_FN_SUPPORTED[self.window]
+        except KeyError:
+            raise NotImplementedError(
+                f"Current implementation doesn't support {self.window} window. "
+                f"Please choose one from {list(WINDOW_FN_SUPPORTED.keys())}."
+            )
 
         self.stft = lambda x: torch.stft(
             input=x,
@@ -380,7 +390,7 @@ def get_spec(self, audio):
             spec = self.stft(audio)
             if spec.dtype in [torch.cfloat, torch.cdouble]:
                 spec = torch.view_as_real(spec)
-            spec = torch.sqrt(spec.pow(2).sum(-1) + 1e-9)
+            spec = torch.sqrt(spec.pow(2).sum(-1) + EPSILON)
         return spec
 
     def get_log_mel(self, audio):
@@ -436,7 +446,6 @@ def __getitem__(self, index):
         # Load alignment prior matrix if needed
         align_prior_matrix = None
         if AlignPriorMatrix in self.sup_data_types_set:
-            align_prior_matrix = None
             if self.use_beta_binomial_interpolator:
                 mel_len = self.get_log_mel(audio).shape[2]
                 align_prior_matrix = torch.from_numpy(self.beta_binomial_interpolator(mel_len, text_length.item()))
@@ -472,7 +481,7 @@ def __getitem__(self, index):
 
             if self.pitch_mean is not None and self.pitch_std is not None and self.pitch_norm:
                 pitch -= self.pitch_mean
-                pitch[pitch == -self.pitch_mean] = 0.0  # Zero out values that were perviously zero
+                pitch[pitch == -self.pitch_mean] = 0.0  # Zero out values that were previously zero
                 pitch /= self.pitch_std
 
             pitch_length = torch.tensor(len(pitch)).long()
diff --git a/tests/collections/tts/test_torch_tts.py b/tests/collections/tts/test_torch_tts.py
index e4e3270eadce..62876f1d4d59 100644
--- a/tests/collections/tts/test_torch_tts.py
+++ b/tests/collections/tts/test_torch_tts.py
@@ -71,3 +71,27 @@ def test_raise_exception_on_not_supported_sup_data_types(self, test_data_dir):
                     g2p=EnglishG2p(),
                 ),
             )
+
+    @pytest.mark.run_only_on('CPU')
+    @pytest.mark.unit
+    @pytest.mark.torch_tts
+    def test_raise_exception_on_not_supported_window(self, test_data_dir):
+        manifest_path = os.path.join(test_data_dir, 'tts/mini_ljspeech/manifest.json')
+        sup_path = os.path.join(test_data_dir, 'tts/mini_ljspeech/sup')
+        with pytest.raises(NotImplementedError):
+            dataset = TTSDataset(
+                manifest_filepath=manifest_path,
+                sample_rate=22050,
+                sup_data_types=["pitch"],
+                sup_data_path=sup_path,
+                window="not_supported_window",
+                text_tokenizer=EnglishPhonemesTokenizer(
+                    punct=True,
+                    stresses=True,
+                    chars=True,
+                    space=' ',
+                    apostrophe=True,
+                    pad_with_space=True,
+                    g2p=EnglishG2p(),
+                ),
+            )