Fir_dbl_col - david-macmahon/wiki_convert_test GitHub Wiki
Block: FIR Double Column (fir_dbl_col)
Block Author: Aaron Parsons
Document Author: Ben Blackman
Summary
Takes in real and imaginary numbers to be multiplied by the coefficients and then the filter sums the real and imaginary parts separately. Then both sums are output as well as a delayed version of the unchanged inputs.
Mask Parameters
| Parameter | Variable | Description |
|---|---|---|
| Inputs | n_inputs | The number of real inputs and the number of imaginary inputs. |
| Coefficients | coeff | A vector of coefficients of this FIR. Should be the same number of coefficients as inputs. |
| Add Latency | add_latency | The latency of the internal adders. |
| Mult Latency | mult_latency | The latency of the internal multipliers. |
Ports
| Port | Dir | Data Type | Description |
|---|---|---|---|
| real | IN | Inherited | This real input is to be multiplied by one of the coefficients. |
| imag | IN | Inherited | This imaginary input is to be multiplied by one of the coefficients. |
| real_back | IN | Inherited | These real inputs correspond to the second half of the input stream. They get added to one of the real inputs before being multiplied by the coefficient. |
| imag_back | IN | Inherited | These imaginary inputs correspond to the second half of the input stream. They get added to one of the imag inputs before being multiplied by the coefficient. |
| real_out | OUT | Inherited | This output is real delayed by 1 cycle. |
| imag_out | OUT | Inherited | This output is imag delayed by 1 cycle. |
| real_back_out | OUT | Inherited | This output is real_back delayed by 1 cycle. |
| imag_back_out | OUT | Inherited | This output is imag_back delayed by 1 cycle. |
| real_sum | OUT | Inherited | This is the sum of all the multiplications between real and real_back and their corresponding coefficients. |
| imag_sum | OUT | Inherited | This is the sum of all the multiplications between imag and imag_back and their corresponding coefficients. |
Description
Usage
This block takes in a number of inputs in parallel and outputs a delayed
version of them and also multiplies the inputs by the coefficients. Then
real_sum and imag_sum are computed and are delayed due to the
latency in the adders which depends both on the add_latency and the
number of inputs. For example, if you choose the number of inputs to be
2, then there will be 2 real and 2 real_back input ports along with
2 imag and 2 imag_back input ports. The FIR Double Column blocks
takes advantage of the symmetric filter tap coefficients by adding the
first and last inputs together before multiplying by the coefficient.
This results in a more efficient FIR filter column.