UpFIRDnConverter

Overview

Converts sample rate of input wire and outputs data at new sample rate.

Discussion

Sample rate converter. The output sample rate SampleRateOut = L/D*SampleRateIn , where L is the Interpolation factor and D is the Decimation factor. The input block size must be an integer multiple of D. The length of the filter must be greater than L. L, D, and the optimal value for N can be calculated using the inspector.

Module Pack

Advanced

ClassID

classID = 1427

Type Definition

typedef struct _ModuleUpFIRDnConverter
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
FLOAT32 gd;                                   // Group Delay or latency, calculated result
INT32 KAISER;                                 // Filter type constant
INT32 PARKS_MCCLELLAN;                        // Filter type constant
INT32 CUSTOM;                                 // Filter type constant
FLOAT32 fin;                                  // Input Sample Rate
INT32 L;                                      // Interpolation factor
INT32 D;                                      // Decimation factor
INT32 filterType;                             // filter type of FIR
INT32 ND;                                     // Integer multiplication factor
INT32 N;                                      // length of FIR filter
INT32 NQ;                                     // Size of QBUF, >= 2*Q, where Q = N/L (integer divide)
INT32 IQ;                                     // QBUF index
INT32 JQ;                                     // QBUF index, moving address index.
INT32 NC;                                     // Size of array COFS
INT32 NCOEF;                                  // Size of COEF array
FLOAT32* QBUF;                                // Internal buffer for storage of state variables of FIR filter
INT32* ICTR;                                  // Buffer for storing control data
FLOAT32* COEF;                                // FIR symmetric filter coeffs
FLOAT32* COFS;                                // scrambled coeffs for FIR filter
} ModuleUpFIRDnConverterClass;

Variables

Properties

Name	Type	Usage	isHidden	Default Value	Range	Units
gd	float	const	0	0.1319	Unrestricted	msec
KAISER	int	const	1	1	Unrestricted
PARKS_MCCLELLAN	int	const	1	2	Unrestricted
CUSTOM	int	const	1	3	Unrestricted
fin	float	parameter	1	48000	Unrestricted
L	int	const	1	3	Unrestricted
D	int	const	1	4	Unrestricted
filterType	int	const	1	1	Unrestricted
ND	int	derived	1	8	Unrestricted
N	int	const	1	39	Unrestricted
NQ	int	const	1	26	Unrestricted
IQ	int	const	1	13	Unrestricted
JQ	int	derived	1	13	Unrestricted
NC	int	const	1	39	Unrestricted
NCOEF	int	const	1	20	Unrestricted
QBUF	float*	derived	1	[1 x 26]	Unrestricted
ICTR	int*	derived	1	[6 x 1]	Unrestricted
COEF	float*	derived	0	[20 x 1]	Unrestricted
COFS	float*	derived	1	[39 x 1]	Unrestricted

Pins

Input Pins


Name	in
Description	Input signal
Data type	float
Channel range	Unrestricted
Block size range	Unrestricted
Sample rate range	Unrestricted
Complex support	Real

Output Pins


Name	out
Description	Output signal
Data Type	float

Matlab Usage

File Name: up_fir_dn_converter_module.m 
 M=up_fir_dn_converter_module(NAME, L, D, N, filterType) 
 Performs rational sample rate conversion 

 Arguments: 
     NAME - Name of the module 
     L - Interpolation factor 
     D - Decimation factor 
     N - length of FIR filter used in the conversion process 
     filterType - Type of filter 

 Author: Darrel Judd