.. index:: pair: class; xf::dsp::aie::fir::decimate_hb::fir_decimate_hb_graph
.. _doxidclassxf_1_1dsp_1_1aie_1_1fir_1_1decimate__hb_1_1fir__decimate__hb__graph:
.. _cidxf::dsp::aie::fir::decimate_hb::fir_decimate_hb_graph:
template class xf::dsp::aie::fir::decimate_hb::fir_decimate_hb_graph
====================================================================
.. toctree::
:hidden:
.. codeblock:: cpp
:class: overviewcodeblock
#include "fir_decimate_hb_graph.hpp"
Overview
~~~~~~~~
fir_decimate_hb is a Halfband Decimation FIR filter
These are the templates to configure the halfband decimator FIR class.
.. rubric:: Parameters:
.. listtable::
:widths: 20 80
*
 TT_DATA
 describes the type of individual data samples input to and output from the filter function. This is a typename and must be one of the following: int16, cint16, int32, cint32, float, cfloat.
*
 TT_COEFF

describes the type of individual coefficients of the filter taps. It must be one of the same set of types listed for TT_DATA and must also satisfy the following rules:
* Complex types are only supported when TT_DATA is also complex.
* 32 bit types are only supported when TT_DATA is also a 32 bit type,
* TT_COEFF must be an integer type if TT_DATA is an integer type
* TT_COEFF must be a float type if TT_DATA is a float type.
*
 TP_FIR_LEN
 is an unsigned integer which describes the number of taps in the filter. TP_FIR_LEN must be in the range 4 to 240 inclusive and must satisfy (TP_FIR_LEN +1)/4 = N where N is a positive integer.
*
 TP_SHIFT
 is describes power of 2 shift down applied to the accumulation of FIR terms before output. TP_SHIFT must be in the range 0 to 61.
*
 TP_RND
 describes the selection of rounding to be applied during the shift down stage of processing. TP_RND must be in the range 0 to 7 where 0 = floor (truncate) eg. 3.8 Would become 3. 1 = ceiling e.g. 3.2 would become 4. 2 = round to positive infinity. 3 = round to negative infinity. 4 = round symmetrical to infinity. 5 = round symmetrical to zero. 6 = round convergent to even. 7 = round convergent to odd. Modes 2 to 7 round to the nearest integer. They differ only in how they round for values of 0.5.
*
 TP_INPUT_WINDOW_VSIZE
 describes the number of samples in the window API used for input to the filter function. The number of values in the output window will be TP_INPUT_WINDOW_VSIZE divided by 2 by virtue the halfband decimation factor. Note: Margin size should not be included in TP_INPUT_WINDOW_VSIZE.
*
 TP_CASC_LEN
 describes the number of AIE processors to split the operation over. This allows resource to be traded for higher performance. TP_CASC_LEN must be in the range 1 (default) to 9.
*
 TP_DUAL_IP
 is an implementation tradeoff between performance and data bank resource. When set to 0, the FIR performance may be limited by load contention. When set to 1, two ram banks are used for input.
*
 TP_USE_COEFF_RELOAD

allows the user to select if runtime coefficient reloading should be used. This currently is only available for single kernel filters. When defining the parameter:
* 0 = static coefficients, defined in filter constructor
* 1 = reloadable coefficients, passed as argument to runtime function
.. refcodeblock:: cpp
:class: overviewcodeblock
template <
typename TT_DATA,
typename TT_COEFF,
unsigned int TP_FIR_LEN,
unsigned int TP_SHIFT,
unsigned int TP_RND,
unsigned int TP_INPUT_WINDOW_VSIZE,
unsigned int TP_CASC_LEN = 1,
unsigned int TP_DUAL_IP = 0,
unsigned int TP_USE_COEFF_RELOAD = 0,
unsigned int TP_NUM_OUTPUTS = 1
>
class fir_decimate_hb_graph: public graph
// fields
port :ref:`in`
port