[填空题]
A cassette player isnbj nf 8g3dk:/x*-ffg sgq+f)kj+s* sy aid to have a signal-to-noise ratio of 58 dB, whereas for a CD player it is 95 dB.kq+ fsyj)s+ g* What is the ratio of intensities of the signal and the background noise for each device? 58 dB = $ \times10^{ 5}$ dB = $ \times10^{9 }$
