User`s manual

134
4.8.2: Spectrum Analyzer Window
Application:
To properly utilize the processing tools, it is often necessary to measure the frequency
characteristics of the input signal. This assists in determining the type of filtering needed.
Also, after processing the signal, it may be desirable to compare the frequency characteristics
of each digital filter output to those of the input signal, thus determining the effectiveness of
each digital filter. A dual-channel FFT spectrum analyzer with selectable inputs is ideal for
accomplishing these tasks.
The dual-channel FFT spectrum analyzer is used to view the frequency spectrum of the signal
at any stage of the enhancement process. Two traces, Trace 1 and Trace 2, can be displayed
either simultaneously or separately. Either trace can be configured to the signal spectrum at
any point in the processing chain. The Averager feature combines successive spectra to
achieve a slower, smoother display. Each trace consists of 460 spectral lines with a useable
dynamic range of 70dB. Adjustable Gain controls allow up to 40dB of digital gain to be
applied to each trace to boost low level signals to better fit within the this dynamic range. An
overall dynamic range of 110 dB is thus available.
A moveable Marker allows frequency and magnitude readout at any point in the two spectra.
The Find Peak feature allows the marker to be moved instantly to the largest magnitude
displayed.
Finally, the Spectrum Analyzer window is fully sizeable, and can utilize all the available
display area for viewing if desired. Controls can be hidden using the Hide Controls checkbox,
and printouts can be generated using the Print button.