题目内容
（请给出正确答案）
[单选题]
对信号进行FM调制，当考虑到频率的稳定性时，一般采用
A.直接调频，非相干解调
B.间接调频，非相干解调
C.直接调频，相干解调
D.间接调频，相干解调
提问人：网友cocktail
发布时间：2022-01-07
如搜索结果不匹配，请 
A、输出信噪比
B、输入信噪比
C、信道信噪比
D、信道带宽
题目内容
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更多“对信号进行FM调制，当考虑到频率的稳定性时，一般采用”相关的问题
第5题
The resolution of full high definition television (Full HD) is 1920×1080 and the frame rate is 60 Hz. For each pixel, the quantization levels of different color samplings (R, G, B) are all set to 4096. Then, the number of bits per second and the minimum bandwidth required to transmit this video signals are about T and W (Hz), respectively, where the channel SNR=30(dB). Hint: C=W*log2(1+SNR).
A、T=300M, W=30M
B、T=3000M, W=1000M
C、T=3000M, W=300M
D、T=1000M, W=300M
第6题
In a digital communication system, the Nyquist interval of signal 
should be millisecond (ms).
should be millisecond (ms).
A、1.25
B、2.5
C、5
D、10
第7题
An analog signal m(t) with zero mean is a stationary process. Its frequency range is 0(Hz) ~ 8000(Hz) and its amplitude is uniformly distributed between -5(V) ~ +5(V). Then, the minimum Nyquist sampling frequency for this signal m(t) is f (Hz) , the average power is P (W). Assuming a uniform quantizer for this signal and the step size is D=0.04(V), the minimum number of quantization bits is R .
A、f=8000, P=25, R=8
B、f=16000, P=25/2, R=7
C、f=8000, P=25/3, R=9
D、f=16000, P=25/3, R=8
第8题
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 (
).
).
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
第9题
A compact disk (CD) is used to store music. Suppose that both the two independent channels of the true stereo music with the highest frequency 22.05 kHz are sampled at the Nyquist sampling rate, then the sampling rate for each channel is f (kHz). The encoded PCM is to have an average SNR of at least 96 dB. Then, the minimum number of the uniform quantization of the sampled data should be R bits. If the Beethoven's Symphony No. 9 with 74 minutes in PCM data can be stored in CD, the minimum storage capacity of the CD should be T (MB, Megabyte). (Hint:
).
A、f=44.1, R=16, T=783
B、f=22.05, R=16, T=392
C、f=44.1, R=15, T=700
D、f=44.1, R=16, T=392
第10题
A 1G bytes flash memory is used to store PCM data. Suppose that a VF (voice-frequency) signal is sampled at 8kHz and the PCM data with R bits quantization is to have an average SNR of at least 30dB. Then, about T hours of VF signal in PCM data can be stored in this flash memory. (Hint: 
).
).
A、T=111.11
B、T=55.56
C、T=27.78
D、T=13.89
