Uniformly modulated polyphase DFT filter bank: analysis
Uniformly modulated polyphase DFT filter bank: synthesis
Proxy of C++ gr::filter::firdes class
Uniformly modulated polyphase DFT filter bank: synthesis
Uniformly modulated polyphase DFT filter bank: analysis
Builds a low pass filter.
Parameters: 


Builds a band pass filter.
Parameters: 


Builds a band pass filter with complex taps by making an LPF and spinning it up to the right center frequency
Parameters: 


Builds a band reject filter spinning it up to the right center frequency
Parameters: 


Convert a stopband attenuation in dB to an absolute value
Convert passband ripple spec expressed in dB to an absolute value
FIR order estimator (lowpass, highpass, bandpass, mulitiband).
(n, fo, ao, w) = remezord (f, a, dev) (n, fo, ao, w) = remezord (f, a, dev, fs)
(n, fo, ao, w) = remezord (f, a, dev) finds the approximate order, normalized frequency band edges, frequency band amplitudes, and weights that meet input specifications f, a, and dev, to use with the remez command.
Use remez with the resulting order n, frequency sequence fo, amplitude response sequence ao, and weights w to design the filter b which approximately meets the specifications given by remezord input parameters f, a, and dev:
b = remez (n, fo, ao, w)
(n, fo, ao, w) = remezord (f, a, dev, Fs) specifies a sampling frequency Fs.
Fs defaults to 2 Hz, implying a Nyquist frequency of 1 Hz. You can therefore specify band edges scaled to a particular applications sampling frequency.
In some cases remezord underestimates the order n. If the filter does not meet the specifications, try a higher order such as n+1 or n+2.
FIR lowpass filter length estimator. freq1 and freq2 are normalized to the sampling frequency. delta_p is the passband deviation (ripple), delta_s is the stopband deviation (ripple).
Note, this works for high pass filters too (freq1 > freq2), but doesnt work well if the transition is near f == 0 or f == fs/2
From Herrmann et al (1973), Practical design rules for optimum finite impulse response filters. Bell System Technical J., 52, 76999
FIR bandpass filter length estimator. freq1 and freq2 are normalized to the sampling frequency. delta_p is the passband deviation (ripple), delta_s is the stopband deviation (ripple).
From Mintzer and Liu (1979)
Make a Polyphase Filter channelizer (complex in, complex out, floatingpoint taps)
This simplifies the interface by allowing a single input stream to connect to this block. It will then output a stream for each channel.
Make a Polyphase Filter interpolator (complex in, complex out, floatingpoint taps)
The block takes a single complex stream in and outputs a single complex stream out. As such, it requires no extra glue to handle the input/output streams. This block is provided to be consistent with the interface to the other PFB block.
Make a Polyphase Filter decimator (complex in, complex out, floatingpoint taps)
This simplifies the interface by allowing a single input stream to connect to this block. It will then output a stream that is the decimated output stream.
Convenience wrapper for the polyphase filterbank arbitrary resampler.
The block takes a single complex stream in and outputs a single complex stream out. As such, it requires no extra glue to handle the input/output streams. This block is provided to be consistent with the interface to the other PFB block.
Convenience wrapper for the polyphase filterbank arbitrary resampler.
The block takes a single float stream in and outputs a single float stream out. As such, it requires no extra glue to handle the input/output streams. This block is provided to be consistent with the interface to the other PFB block.
Convenience wrapper for the polyphase filterbank arbitrary resampler.
The block takes a single complex stream in and outputs a single complex stream out. As such, it requires no extra glue to handle the input/output streams. This block is provided to be consistent with the interface to the other PFB block.
Make a Polyphase Filter channelizer (complex in, complex out, floatingpoint taps)