209
Spectral Controls: Frequency
Access this control window from the Math menu Spectral Controls command or the Controls button on
the Spectral Setup control window.
Overview
Use the Frequency controls to operate the instrument like a spectral analyzer.
To Use
Click the individual controls and use the multipurpose knobs to select
Center Freq, Freq Span, Res BW, and Ref Level (Reference Level).
Behavior
The maximum frequency span is equal to half of the sample rate. If
you need a higher frequency span, set the sample rate to a larger
value.
The Ref Level (reference level) control is a position control for the
spectral waveform. The position appears at the top of the control
window. The Ref Level control does not change the position with
respect to the reference marker.
Note
The Frequency domain controls interact with the Gating and
Acquisition controls; changing one set of controls may change the
other control settings.
Selecting a Spectral Window
A spectral window determines what the filter shape of the spectral analyzer will be in the
frequency domain. It may be described by a mathematical function that is multiplied point-by-
point times the input data to the spectral analyzer.
The following spectral windows are available with the instrument:
Rectangular
Hamming
Hanning
Kaiser-Bessel
Blackman Harris
Gaussian
Tek Exponential
Flattop2
The windows are listed in the order of their ability to resolve frequencies (resolution bandwidth).
You can easily observe the shape of a window in the frequency domain by feeding a sine wave
into the instrument and setting the center frequency of the spectral analyzer to the same frequency.
Summary of Contents for TDS5000B Series
Page 36: ...36 AFTDS Differential Signal Adapter...
Page 280: ...280 Blackman Harris window...
