用python生成正玄波信号源码解析

一 前记

项目需要生成不同频点的正玄波信号，没找到现成的软件，只能自己写一个了。顺便温习一下python。

二 源码解析：

#!/usr/bin/python
import numpy as np
from scipy import signal
import wave
import struct
import sys

num_samples = 48000
sampling_rate = 48000.0
amplitude = 16000
comptype = 'NONE'
compname = 'not compressed'
nchannels = 1
sampwidth = 2
FILE_NAME = ''

def createSine(frequency,frequency1,play_time):
    # generate the sine wave
    new_wave = [np.sin(2 * np.pi * frequency * x/sampling_rate) + np.sin(2 * np.pi * frequency1 * x/sampling_rate) for x in range(num_samples * play_time)]
    writeWave(new_wave)

def createWave(frequency, frequency1, wave_type, play_time):
    if wave_type == 'sine':
        createSine(frequency,frequency1,play_time)
    else:
        print('Please type in only waveforms from this list! (sine, saw, triangle, square)')

def writeWave(created_wave):
    file = FILE_NAME
    nframes = num_samples
    wav_file = wave.open(file, 'w')
    wav_file.setparams((nchannels, sampwidth, int(sampling_rate), nframes, comptype, compname))
    for s in created_wave:
        # struct.pack with the parameter 'h' means that we're
        # writing the data as binaries, not just the numbers.
        # 'h' stands for hexadecimal.
        # This allows for music players to read the data.
        wav_file.writeframes(struct.pack('h', int(s*amplitude)))

def printSuccessful(wave_type, frequency,frequency1, play_time):
    print('File \'' + FILE_NAME + '\' created!\n' +
      'Wave Type: ' + wave_type + '\n' +
      'Frequency_one: ' + frequency + "hz\n"+
      'Frequency_two: ' + frequency1 + "hz\n"+
      'Play Time: ' + play_time + ' seconds')

def main(wave_type, frequency, frequency1,play_time, file_name):
    frequency_Float = float(frequency)
    frequency_Float1 = float(frequency1)
    wave_type_Str = str(wave_type)
    play_time_Int = int(play_time)
    file_name = str(file_name)
    global FILE_NAME
    if len(file_name) < 4:
        print('your specified filename: \'' + file_name + '\' is too short. The file name must end in \'.wav\'.\n Do you want me to change your file name to end in \'.wav\'? (y/n)')
        answer = input()
        if answer == 'y':
            FILE_NAME = file_name + '.wav'
            createWave(frequency_Float,frequency_Float1,wave_type_Str, play_time_Int)
            printSuccessful(wave_type, frequency, frequency1,play_time)
        elif answer == 'n':
            print('Please press a key to exit.')
            input()
    else:
        FILE_NAME = file_name
        createWave(frequency_Float, frequency_Float1, wave_type_Str, play_time_Int)
        printSuccessful(wave_type, frequency, frequency1,play_time)

if __name__ == '__main__':
    main(sys.argv[1], sys.argv[2], sys.argv[3], sys.argv[4],sys.argv[5])

运行结果：

➜  wave-generator git:(master) ✗ py tone_wave_generator.py sine 900 1800 10 out26.wav
File 'out26.wav' created!
Wave Type: sine
Frequency_one: 900hz
Frequency_two: 1800hz
Play Time: 10 seconds

三 结果分析

生成的wav文件波形图：

对应的频谱图