合同中的数量条款为“1000 m/t with 5％ more or less at seller’s option” ，则卖方交货数量可以是（ ）
受虐妇女综合征反映出受虐妇女在极端情况下可能以暴制暴。（）
下列属于线路纵断面要素的是()
电阻元件的伏安特性曲线是过原点的直线时，称为线性电阻。
哪些系统构成受虐儿童支持系统（）
轨道交通线路之间为完成列车跨线运营而设置的线路是()
下列各项中，不属于集体土地所有权客体的是（ ）。
the signal s(t) shown in figure is tranitted through an awgn channel with noise psd n0/2. suppose a matched filter with impulse response h(t) is used at the receiver, the matched filter output should be:
in amplitude modulation (am), if the carrier wave is over-modulated, envelop detection cannot be used to recover the message signal.
if a =2， what type of modulation does this correspond to ? if a =0， what type of modulation does this correspond to ?
specify the nyquist rate and the nyquist interval for each of the following signals: (1) g(t) = sinc(200t) (2) g(t) = (200t) (3) g(t) = sinc(200t) (200t)
the envelop of a pm or wideband fm signal is constant,whereas the envelop of an am or narrowband fm signal is depent on the message signal.
奄列蛋又称煎蛋卷或煎蛋角,最早起源于西班牙。
the signal s(t) shown in figure is tranitted through an awgn channel with noise psd n0/2. suppose a filter with impulse response h(t) is used at the receiver, the filter output should be:
for m-ary psk signal, as m increased, the bandwidth efficiency will be ____________.
“四大徽班”是指
considering the properties of the autocorrelation function rx(τ) of a random process x(t).
for a digital communication system which can tranit 4800 bits per second with 16-psk modulation, the symbol rate is ________ symbols per second.