sinc [-a att|-b beta] [-p phase|-M|-I|-L] [-t tbw|-n taps] [freqHP]
[-freqLP [-t tbw|-n taps]]
freqHP and freqLP parameters
give the frequencies of the 6dB points of a high-pass and
low-pass filter that may be invoked individually, or together.
If both are given, then freqHP less than freqLP creates a bandpass
filter, freqHP greater than freqLP creates a band-reject filter.
For example, the invocations
sinc 3k sinc -4k sinc 3k-4k sinc 4k-3k |
create a high-pass, low-pass, band-pass, and band-reject filter respectively.
The default stop-band attenuation of 120dB can be overridden
with -a; alternatively, the kaiser-window "beta" parameter can
be given directly with -b.
The default transition band-width of 5% of the total band can be
overridden with -t (and tbw in Hertz); alternatively, the number
of filter taps can be given directly with -n.
If both freqHP and freqLP are given, then a -t or -n option
given to the left of the frequencies applies to both frequencies;
one of these options given to the right of the frequencies
applies only to freqLP.
The -p, -M, -I, and -L options control the filter's phase
response; see the rate effect for details.