几个dsp的问题(期末考试题) - 未名空间MITBBS历史存档

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几个dsp的问题(期末考试题)

几个dsp的问题(期末考试题)# EE - 电子工程

e*a2007-12-14 08:12

1 楼

我们的final exam里的.很多概念都不懂(找不到老师答疑,他也经常不来上课,从没有
solution).
可能很多人觉得题目简单,但是老师从来没说过,我们的参考书上也找不到,请大家帮忙.
明天考试.谢谢!
A comosite audio signal is sample at 100KHz. In addition to the audio
confined to the frequency band 0Hz through 20KHz, it contains a digital sub-
carrier centered at 50KHz with a double sideband supperessed carrier, second
audio signal with two-sided bandwidth 20KHz.
1. Estimate the DC gain of the filter if its largest coeffieient has been
normalized to unity.

z*n2007-12-14 08:12

2 楼

Question1:
the sampler works at 100kHz. Then for the double sideband
signal with compressed carrier at 50kHz, the lower sideband
will pass through, the higer sideband will be regarded as
alias of lower one. So the effect is that the lower sideband
is doubled in amplitude. And this is the largest coefficient,
so the coefficents for the signal below 20kHz will be 1/2=0.5
this includes the DC gain.

忙.
sub-
second

【在 e**a 的大作中提到】

: 我们的final exam里的.很多概念都不懂(找不到老师答疑,他也经常不来上课,从没有
: solution).
: 可能很多人觉得题目简单,但是老师从来没说过,我们的参考书上也找不到,请大家帮忙.
: 明天考试.谢谢!
: A comosite audio signal is sample at 100KHz. In addition to the audio
: confined to the frequency band 0Hz through 20KHz, it contains a digital sub-
: carrier centered at 50KHz with a double sideband supperessed carrier, second
: audio signal with two-sided bandwidth 20KHz.
: 1. Estimate the DC gain of the filter if its largest coeffieient has been
: normalized to unity.

z*n2007-12-14 08:12

3 楼

The spectrum contains a set of 16KHz narrowband signals separated by 20KHz
center frequencies. We want to design a FIR filter centered on the band
located at 100KHz and reject the remaining signals by 88dB.
1. We are considering using using an FFT to separate the spectal bands; what
minimun length (un-windowed) FFT is required to resolve the bands?

e*a2007-12-14 08:12

4 楼

Thanks!!!