GASK
所属分类：雷达系统
开发工具：matlab
文件大小：1194KB
下载次数：2
上传日期：2020-02-24 07:21:24
上 传 者：
sh-1993
说明： 基于高斯ASK调制的超声室内定位
(Gaussian ASK modulation-based Ultrasonic indoor localization)
文件列表:
GASK_gen_signal.wav (2092, 2020-02-24)
GASK_test_signal.wav (1950764, 2020-02-24)
GASKmodemodulation.m (3417, 2020-02-24)
image (0, 2020-02-24)
image\GASK_demodulation.PNG (13638, 2020-02-24)
image\GASK_modulation.PNG (15057, 2020-02-24)
# GASK (Gaussian Amplitude Shift Keying)
## Introduction
GASK provides an optimized modulation scheme for Ultrasonic indoor localization on mobile devices.
We have written the example code in matlab R2018b and provide an audio file and an .m file.
## Modualtion Process
Input return to zero(RZ) bits are convolved with a Gaussian filter to create a smooth bit stream.
```
// Gaussian parameter
samples_per_bit = ***;
n = [-samples_per_bit/2:samples_per_bit/2];
B = 0.5;
k1 = sqrt(2*pi/reallog(2));
h = k1*B*exp(-2*k1*k1*pi.*B.*B*(1/samples_per_bit.*n).^2);
...
// Gaussian Filtering
s = filter(h,1,bit_raw);
```
## Demodualtion Process
In the demodulation process, the carrier signal is processed by a band pass filter, and then a low pass filter is used to remove noise.
```
// 2.1 Read the modulated signal
[z,Fs] = audioread('GASK_test_signal.wav');
// 2.2 Band Pass Filter
Wn = [15000 19000];
[b,a] = butter(5,Wn/(SampleRate/2),'bandpass');
de_x0 = filter(b,a,z);
// 2.2 Low Pass Filter
[b,a] = butter(4,500/(SampleRate/2),'low');
de_x0 = filter(b,a,abs(de_x0));
// 2.3 normalization
de_x0 = de_x0./max(de_x0);
```
At the end of the GASK demodulation process, the received bits are extracted through the slicer for decion.
## Demonstration
Additional supplementary videos are available for further understanding.
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