A. 該信號(hào)是有始有終信號(hào) B. 該信號(hào)是按指數(shù)規(guī)律增長(zhǎng)的信號(hào) C. 該信號(hào)是按指數(shù)規(guī)律衰減的信號(hào) D. 該信號(hào)的幅度既不增長(zhǎng)也不衰減而等于穩(wěn)定值,或隨時(shí)間t,tn成比例增長(zhǎng)的信號(hào)
已知某因果連續(xù)時(shí)間LTI系統(tǒng),其頻率響應(yīng)為,對(duì)于某一輸入信號(hào)x(t)所得輸出信號(hào)的傅里葉變換為,則該系統(tǒng)的輸入x(t)=()
A. B. C. D.
已知連續(xù)信號(hào)x(t)的波形如圖所示,則其傅里葉變換為()
A.Sa(ω)+Sa(2ω) B.2Sa(ω)+4Sa(2ω) C.Sa(ω)+2Sa(2ω) D.4Sa(ω)+2Sa(2ω)