Altera CIC MegaCore Function Manuale Utente Scaricare il pdf (Pagina 23)

Generally, only equalize the response in the passband, but you can sample further than the passband to

fine tune the cascaded response of the filter chain.

The CIC IP core generates a MATLAB script <variation_name>_fir_comp_coeff.m in the project directory.

You can run this script in MATLAB to generate FIR coefficients that provide appropriate passband

equalization. The generated coefficients are saved in a text file, for use by the Altera FIR Compiler

MegaCore function.

The MATLAB script requires the following parameters for the compensation FIR filter:

• L: FIR filter length, which is same as the number of taps or the number of coefficients

• F

FIR filter sample rate in Hz before decimation/interpolation

• F

: FIR filter cutoff frequency in Hz

• B: Coefficient bit width if coefficients are written in fixed-point numbers

Figure 3-6: CIC and Compensation Filter Responses

Related Information

AN455: Understanding CIC Compensation Filters

CIC IP Core Parameters

Table 3-2: CIC IP Core Parameters

Parameter Value Description

Filter Specification

Filter type Decimator,

Interpolator

Selects a decimator or interpolator.

UG-CIC

2014.12.15

CIC IP Core Parameters

3-7

CIC IP Core Functional Description

Altera Corporation

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Altera CIC MegaCore Function Manuale Utente Pagina 23