# FIR Narrowband Filtering (G Dataflow)

Filters an input sequence using a specific interpolated FIR (IFIR) filter.

##### Programming Patterns

You can use the FIR Narrowband Filter Design node to generate the IFIR Filter for this node.

## signal

The input signal.

This input can be a 1D array of double-precision, floating-point numbers or a 1D array of complex double-precision, floating-point numbers.

## IFIR filter

The IFIR filter.

### filter type

Passband of the filter.

Name Description
Lowpass

Uses a lowpass filter.

Highpass

Uses a highpass filter.

Bandpass

Uses a bandpass filter.

Bandstop

Uses a bandstop filter.

Default: Lowpass

### interpolation

The interpolation factor M.

The model filter is stretched by interpolation times.

### Model Filter

The coefficients of the model filter.

### Image Suppressor

The coefficients of the filter image suppressor.

## error in

Error conditions that occur before this node runs. The node responds to this input according to standard error behavior.

Default: No error

Filtered signal.

## error out

Error information. The node produces this output according to standard error behavior.

## Algorithm for Calculating the Delay for the Filter

The overall filter is a linear-phase FIR filter. This node calculates the delay for the filter using the following equation:

$\mathrm{delay}=\frac{\left[\left({N}_{G}-1\right)M+{N}_{I}\right]}{2}$

where

• NG is the number of elements in Model Filter
• NI is the number of elements in Image Suppressor
• M is the value of interpolation

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported