Overview
Converts sample rate of input wire and outputs data at new sample rate.
Discussion
Sample rate converter.\n The output sample rate is computed by L/D*SampleRateIn = SampleRateOut. If the ratio of the input sample rate to the desired output sample rate is irrational, the desired output sample rate will not equal the actual output sample rate. The input block size must be an interger multiple of D. The length of the filter must be > than L. L, D, and the optimal value for N can be calculated using the inspector.
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