User`s guide

FIR Interpolation

5-203

input matrix) appears in the output as sample M

+1, followed by L-1

interpolated values, the second filtered input sample, and so on. See the

example below for an illustration of this case.

See “Excess Algorithmic Delay (Tasking Latency)” on page 3-91 and “The

Simulation Parameters Dialog Box” in the Simulink documentation for more

information about block rates and Simulink’s tasking modes.

Example Example 1

Construct the frame-based model shown below.

Adjust the block parameters as follows.

•Configure the Signal From Workspace block to generate a two-channel

signal with frame size of 4 and sample period of 0.25. This represents an

output frame period of 1 (0.25

∗4). The first channel should contain the

positive ramp signal 1, 2, ..., 100, and the second channel should contain the

negative ramp signal -1, -2, ..., -100.

Signal = [(1:100)' (-1:-1:-100)']

- Sample time = 0.25

- Samples per frame = 4

•Configure the FIR Interpolation block to interpolate the two-channel input

by increasing the output frame rate by a factor of 2 relative to the input

frame rate. Use a third-order filter (m=3) with normalized cutoff

frequency, f

, of 0.25. (Note that f

and m satisfy f

≤ 1/L and m >L.)

FIR filter coefficients = fir1(3,0.25)

- Interpolation factor = 2

- Framing = Maintain input frame size