A.如果x(t)是奇函數(shù),則傅里葉展開系數(shù)an=0,bn=0,n=1,2,3,4,5,6B.如果x(t)是偶函數(shù),則傅里葉展開系數(shù)an=0,n=1,2,3,4,5,6C.如果x(t)是偶函數(shù),則傅里葉展開系數(shù)an=0,bn=0,n=1,2,3,4,5,6D.如果x(t)是偶函數(shù),則傅里葉展開系數(shù)bn=0,n=1,2,3,4,5,6
A.信號的功率譜是幅值譜的平方B.信號的功率譜是虛頻譜的平方C.信號的功率譜是相頻譜的平方D.信號的功率譜是實(shí)頻譜的平方
按傅里葉變換理論,周期信號可以展開為一組正交的正弦信號和余弦信號,對下圖所示的50Hz的方波信號,請問哪個展開式是對的?()
A.0.5*(12/π)*{sin(2π50t)+sin(2π150t)/3+sin(2π250t)/5+sin(2π350t)/7+......}+0.5*(12/π)*{cos(2π50t)+cos(2π150t)/3+cos(2π250t)/5+cos(2π350t)/7+......}B.(12/π)*{sin(2π50t)+sin(2π150t)/3+sin(2π250t)/5+sin(2π350t)/7+......}C.(12/π)*{sin(2π50t)+sin(2π150t)/3+sin(2π250t)/5+sin(2π350t)/7+......}+(12/π)*{cos(2π50t)+cos(2π150t)/3+cos(2π250t)/5+cos(2π350t)/7+......}D.(12/π)*{cos(2π50t)+cos(2π150t)/3+cos(2π250t)/5+cos(2π350t)/7+......}