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Re: Dynamic range

From: Eduardo Murphy
Remote Name: 152.163.100.197

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Hi Gevenag: Following are the definitions from the Vibration Institute regarding vertical and horizontal resolution: Vertical resolution is defined as 20 log(2^number of bits/2) So if you have an analog to digital converter with 16 bits, dynamic range equals 90.3 dB. If the converter handles +5 to -5 volts, the smallest voltage change that it can see is 10 / 2^16 = 0.153 mV. Horizontal resolution is defined as 2*Fmax*WindowFactor/Number of lines. So even for a rectangular window with a factor of 1 the resolution is half of simply dividing fmax/number of lines. For a Hanning window, the factor is 1.5. For example, if fmax = 1000 Hz and 800 lines with a Hanning window, your resolution will be 3.75 Hz and not 1.25 Hz as most vendors state. Regards Eduardo Murphy

Last changed: October 16, 2007