Manual

PC Oscilloscope PCSU100015

View / Markers (FFT) f & Spectral Density dBV/sqrt(Hz)

This image shows the spectrum of the band limited noise signal.

The analysis of noise in the frequency domain shows the distribution of the noise amplitude as a

function of frequency.

Using the

Spectral Density

marker and the Frequency marker, the voltage spectral density (V

SdBV

)

and the noise bandwidth (B

) can be read from the spectrum analyzer display.

First convert the voltage spectral density to

This can be accomplished using the following calculation:

This is the magnitude of the spectrum normalized to a 1 Hz bandwidth.

You may calculate the noise voltage over any bandwidth by multiplying this value by the square root of

the bandwidth.

Assuming a 6 kHz bandwidth, the total output noise voltage is:

(See the V

rms

value of the oscilloscope waveform image of this noise signal.)