5.R-L-C串联电路谐振的条件是（ ） A: ωL=ωC B: L= C C: ωL=1/ωC D: C=1/L

A signal s(t)=3cos(20pt) (V) is quantized by a uniform quantizer, the step size of the quantizer is 0.1(V), then the minimal number of quantization level is L , the number of bits per sample is at least R , and the variance of the quantization error is T ([img=22x22]1803a28ec2869ac.png[/img]). A: L=60, R=5, T=0.000833 B: L=30, R=5, T=0.000833 C: L=60, R=5, T=0.001667 D: L=60, R=6, T=0.000833

‏A signal s(t)=3cos(20pt) (V) is quantized by a uniform quantizer, the step size of the quantizer is 0.1(V), then the minimal number of quantization level is L , the number of bits per sample is at least R , and the variance of the quantization error is T ([img=22x22]1802e166a76be1c.png[/img]).‎ A: L=60, R=5, T=0.000833 B: L=30, R=5, T=0.000833 C: L=60, R=5, T=0.001667 D: L=60, R=6, T=0.000833

设码符号数为 r，码字长度集合为 l，则下列码符号数和码字长度集合能构成即时码的是（ ）。 A: r=2, l={1,3,3,3,4,4} B: r=3, l={1,1,2,2,3,3,3} C: r=5, l={1,1,1,1,1,8,9} D: r=2, l={1,2,3,3,4} E: r=4, l={1,2,3,3,4}

铁磁性物质的磁导率（） A: μr＞l B: μr=l C: μr＜l D: μr＞＞l

RC、RL 电路的时间常数 τ分别等于( )。 A: RC、 L /R B: RC、 R/ L C: R /C 、 R/ L D: R/ C 、 L/ R

RC、RL电路的时间常数 τ 分别等于（ ). A: RC、R/L B: RC、L/R C: C/R、L/R D: C/R、R/L

RL串联电路的时间常数τ=( )。 A: R×L B: R/L C: L/R D: 1/(R×L)

4 Complete the words. ► l u n g c a n c e r lung cancer 1 m _ m _ r _ l _ _ s s ____ 2 a r _ r _ t i c ____ 3 b r _ _ n ____ 4 b l _ _ _ ____ 5 s t r _ _ e ____ 6 h _ _ r t d _ s _ _ s e ____ 7 d _ s _ b _ l _ t y ____

RL电路的时间常数τ和RC电路的时间常数τ分别为( )。 A: RC,R/L B: L/R,RC C: L/R,C/R D: C/R,R/L