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Table:
Minimum zeropadding factors
for keeping peakfrequency bias
below approximately
percent of the samplingrate divided by
the window length [1]. This table is overly
conservative for peakfrequencies below 1 kHz. Here,
denotes the minimum FFT length, and
denotes the
window length. The zeropadding therefore consists of
zeros.
is calculated using the formulas
in [1] and rounded to two significant digits.
Window Type 
(%) 

Rectangular 

2.1 
Gen. Hamming 

1.2 
Blackman 


Rectangular 

4.1 
Gen. Hamming 

2.4 
Blackman 



Table 5.3 gives zeropadding factors sufficient for keeping
the bias below
Hz, where
denotes the sampling
rate in Hz, and
is the window length in samples. For fundamental
frequency estimation,
can be interpreted as the
relative frequency error ``
'' when the window
length is one period. In this case,
is the fundamental
frequency in Hz. More generally,
is the bandwidth of each
sidelobe in the DTFT of a length
rectangular, generalized
Hamming, or Blackman window (any member of the BlackmanHarris window
family, as elaborated in Chapter 3).
Note from Table 5.3 that the Blackman window requires no
zeropadding at all when only
% accuracy is required in
peakfrequency measurement. It should also be understood that a
frequency error of
% is inaudible in most audio
applications.^{6.10}
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