Merge branch 'master' into L2SDP-1035

applications/lofar2/model/pfb_os/dsp_study_erko.txt

@@ -48,12 +48,18 @@
 #   . Applied DSP No. 9: The z-Domain and Parametric Filter Design
 #     https://www.youtube.com/watch?v=xIN5Mnj_MAk
 # * [NOISESHAPING]
-#   . "Digital Signal Processing Oversampled Analog to Digital Conversion with
-#      Noise Shaping", D.R. Brown --> ADC
-#   . "Noise shaping", Markus Nentwig, December 9, 2012 --> DAC
-#      https://www.dsprelated.com/showarticle/184.php
-#   . "Realisering van Digitale Signaalbewerkende Systemen, Toepassingen",
-#      5N290, TUE, P.C.M. Sommen, --> DAC slide 19, 20,
+#   - ADC:
+#     . "Digital Signal Processing Oversampled Analog to Digital Conversion
+#        with Noise Shaping, D.R. Brown
+#        https://spinlab.wpi.edu/courses/ece503_2014/5-5oversampled_adc_shaped.pdf
+#   - DAC:
+#     . "Digital Signal Processing Oversampled Digital to Analog Conversion
+#        with Noise Shaping", D.R. Brown
+#        https://spinlab.wpi.edu/courses/ece503_2014/5-6oversampled_dac_shaped.pdf
+#     . "Noise shaping", Markus Nentwig, December 9, 2012
+#        https://www.dsprelated.com/showarticle/184.php
+#     . "Realisering van Digitale Signaalbewerkende Systemen, Toepassingen",
+#        5N290, TUE, P.C.M. Sommen, --> DAC slide 19, 20,
 # * [PM-REMEZ] https://pm-remez.readthedocs.io/en/latest/
 #
 # https://ocw.mit.edu/courses/6-341-discrete-time-signal-processing-fall-2005/
@@ -1087,6 +1093,8 @@ c) s-plane and z-plane
     frequencies. An LPF filters the higher frequencies and thus increases the
     effective number of bits of the low pass output, by about 1 bit for first
     order feedback.
+  . Noise shaping implies oversampling, because the noise is pushed outside
+    the application bandwidth.
   . ADC: [NOISESHAPING]
     For an ADC noise shaping requires feedback in the analogue domain, because
     after quantization the error information is only available when comparing
@@ -1101,11 +1109,12 @@ c) s-plane and z-plane
     more detailed accuracy on the analogue input signal level that leads to the
     extra bits for oversampling.
   . DAC: [NOISESHAPING]
-    For a DAC noise shaping uses feedback in the digital domain. The round
-    off LSbits of the LPF output are fed back to the input, so that the noise
-    power is shaped towards higher frequencies. This noise power at higher
-    frequences will be filtered by the analoge LPF that filters the DAC
-    output.
+    For a DAC noise shaping uses feedback in the digital domain. A digital
+    LPF filters the low pass band of the oversampled data and has more bits
+    than the DAC. The round off LSbits of the LPF output are fed back to the
+    input, so that the noise power is shaped towards higher frequencies. This
+    noise power at higher frequences will be filtered by the analoge LPF that
+    filters the DAC output.
 
 
 13) Quadrature Mirror Filter (QMF) [CROCHIERE 7.7, PROAKIS 10.9.6]