- Download
- Welcome to SOFiA
- Who is behind SOFiA
- Feature overview
- System overview
- Function reference
- readVSAdata
- mergeArrayData
- F/D/T
- gauss
- lebedev
- S/W/G
- S/T/C
- W/G/C
- S/F/E
- M/F
- R/F/I
- P/D/C
- I/T/C
- makeMTX
- makeIR
- visual3D
- Coordinate System
- Application Examples
- Example 1
- Example 2
- Example 3
- Example 4
- Example 5
- Example 6
- Example 7
- Example 8
- Array Datasets
- VariSphear system
- Groups and Mailinglists
- Contact and Support
- How to Reference
|
SOFiA application example 2
In the second example we generate a full audio spectrum unity plane wave of order N=5 impinging from Azimuth = 0 and Elevation = pi/2 to an open sphere array sampling on a 110 points Lebedev grid using S/W/G. We observe the array responses in different fft-bins using makeMTX and visual3D. Spatial aliasing artifacts arise at higher frequencies that destroy the plane wave response and produce very high output levels.
File(s)
Run `sofiaAE2.m`.
Output
Code
/*
% SOFiA example 2: Sampled unity plane wave simulation for different kr
% SOFiA Version : R11-1220
clear all;
clc;
% Generate a full audio spectrum plane wave using S/W/G
|
r = 0.1; % Array radius
ac = 0; % Rigid Sphere
FS = 48000; % Sampling Frequency
NFFT = 128; % FFT-Bin
AZ = 0*(pi/180); % Azimuth angle
EL = 90*(pi/180); % Elevation angle |
|
quadrature_grid = sofia_lebedev(110, 0); % EXAMPLE GRID LEB110; No Plo
[fftData, kr] = sofia_swg(r, quadrature_grid, ac, FS, NFFT, AZ, EL);
|
% Spatial Fourier Transform
Nsft = 5; % Transform order
Pnm = sofia_stc(Nsft, fftData, quadrature_grid);
% Make radial filters
Nrf = Nsft; % Radial filter order
dn = sofia_mf(Nrf, kr, ac);
% Make visualization MTX
Nmtx = 5;
krIndex = 15; % Choose the kr-bin (Frequency) to display.
mtxDataLOW = sofia_makeMTX(Nmtx, Pnm, dn, krIndex);
krIndex = 24; % Choose the kr-bin (Frequency) to display.
mtxDataMID = sofia_makeMTX(Nmtx, Pnm, dn, krIndex);
krIndex = 30; % Choose the kr-bin (Frequency) to display.
mtxDataHIGH = sofia_makeMTX(Nmtx, Pnm, dn, krIndex);
krIndex = 40; % Choose the kr-bin (Frequency) to display.
mtxDataVERYHIGH = sofia_makeMTX(Nmtx, Pnm, dn, krIndex);
% Plot Responses for different kr (Example values)
figure(1)
clf();
subplot(2, 2, 1)
sofia_visual3D(mtxDataLOW, 0) % Low Alias
subplot(2, 2, 2)
sofia_visual3D(mtxDataMID, 0); % Some Alias
subplot(2, 2, 3)
sofia_visual3D(mtxDataHIGH, 0); % Strong Alias
subplot(2,2,4)
sofia_visual3D(mtxDataVERYHIGH, 0); % Extreme Alias
|
*/ |
|
|
