matlab-基于DTMF的语音信号包络提取matlab仿真-源码

clc; clear; close all; warning off; addpath(genpath(pwd)); %**************************************************************************** %更多关于matlab和fpga的搜索“fpga和matlab”的CSDN博客: %matlab/FPGA项目开发合作 %https://blog.csdn.net/ccsss22?type=blog %**************************************************************************** envelope_insensitivity = 100; silent_amplitude_threshold = 0.01; % filename = 'Test_DTMF.wav'; info = audioinfo(filename); [y, Fs] = audioread(filename); row_freq = [697; 770; 852; 941]; column_freq = [1209, 1336, 1477, 1633]; freqs = row_freq + column_freq; chars = {{'1', '2', '3', 'A'}; {'4', '5', '6', 'B'}; ... {'7', '8', '9', 'C'}; {'*', '0', '#', 'D'}}; num_strokes = 0; prev_size = 0; while (~(prev_size == length(y))) prev_size = length(y); envelope = imdilate(abs(y), true(envelope_insensitivity, 1)); if (num_strokes == 0) figure; plot(y); xlabel('Samples'); ylabel('Amplitude'); title('Signal'); hold on; plot(envelope, 'r-', 'LineWidth', 2); plot(-envelope, 'r-', 'LineWidth', 2); legend('Data', 'Envelope'); end quiet_parts = envelope < silent_amplitude_threshold; stroke_num_samples = find(quiet_parts == 1, 1, 'first') - 1; quiet_parts_cut = quiet_parts; quiet_parts_cut(1:stroke_num_samples) = []; quiet_num_samples = find(quiet_parts_cut == 0, 1, 'first') - 1; stroke = y(1:stroke_num_samples, :); % the two frequencies that produce maximum power spectral density (PSD) % are almost equal to the dual frequencies [Pxx, F] = periodogram(stroke, rectwin(length(stroke)), length(stroke), Fs); [~, index] = max(Pxx); freq1 = F(index); Pxx(index) = []; [~, index] = max(Pxx); freq2 = F(index); y(1:stroke_num_samples + quiet_num_samples, :) = []; num_strokes = num_strokes + 1; freq_estimated = round(freq1 + freq2); %estimated dual tone frequency distance_squared = (freqs - freq_estimated) .^ 2; %distance of estimated frequency from actual dual tone frequencies [row, column] = find(distance_squared == min(min(distance_squared))); %nearest frequency to the estimation is selected fprintf('%c ', chars{row}{column}); end fprintf('\nNumber of key strokes: %d\n', num_strokes);