Linear Resolution In The Hp 3562A; The Linear Resolution Preset Measurement; 3: Analysis Via Display Selections; High Resolution Zoom Measurement - HP 3562A Operating Manual

Chapter 2:
Frequency Response Measurements with linear Resolution
Linear Resolution in the HP

The Linear Resolution Preset Measurement

High Resolution Zoom Measurement

Analysis via Display Selections

Internal Storage of Results

I ntroduction
Linear resolution is the measurement technique common to all fast-Fourier transform
(F FD based analyzers. Time data is sampled until a data buffer called the "time
record" is filled with a fixed number of time samples. Once the time record is filled,
the fast-Fourier transform of the record is computed and the frequency spectrum is
displayed. For those unfamiliar with the operation of F FT-based analyzers, a good
tutorial explanation is presented in Hewlett-Packard Application Note 243, "Funda­
mentals of Dynamic Signal Analysis"
Common applications of dual-channel F F T analyzers such as the HP 3562A include
frequency response measurements of electronic networks and mechanical struc­
tures. Both of these applications can benefit from the measurement speed, resolution
and versatility found in high-performance Dynamic Signal Analyzers.

Linear Resolution in the HP 3562A

The Linear Resolution mode in the HP 3562A provides 801 lines of frequency resolu­
tion per channel in single- or dual-channel operation. Resolution ranging from 125 Hz
(100 kHz span) to 12.8 11Hz (10.24 mHz span) can be obtained in baseband (O-start)
mode. In zoom mode, resolution as narrow as 25.6 11 Hz (20.48 mHz span) can be
o btained anywhere in the dc-to-100 kHz measurement range of the HP 3562A.
Given two high performance input channels and a built-in signal source, frequency
response measurements are easy to implement with the HP 3562A. The remainder of
this chapter is an introduction to frequency response measurements with the HP
3562A Linear Resolution mode. Baseband and zoom measurements on a low fre­
measurement sequence outlined at the end of Chapter 1, (2) quick configuration of a
quency electronic crystal resonator will be shown to demonstrate: (1) the general
zoom measurement using the X-axis marker and the MARKER VALUE key and (3) a
variety of informative display configurations.
The Linear Resolution Preset Measurement
Given an unknown network, a good starting pOint is a full span base band frequency
response measurement. This can be done very quickly with the general measure­
ment procedure and the Linear Resolution preset
1.
Select Mode At turn-on the HP 3562A is set for Linear Resolution operation. If
the analyzer is on, press the M EAS MODE key and select the
LINEAR RES soft key
2 . Preset Press the green PRESET key The Linear Resolution setup sta te
can be displayed. as shown in Figure
STATEITRACE key
The Entry group arrow keys, knob and keypad will be active.
3 . Set Source Level Press the SOURCE key. then select the SOURCE LEVEL softkey
select the desired output level for the signal source. The random
noise source
4.
Averaging Press the AVG key The Entry group is active; select the number
of averages to be taken. Since random noise will be used for this
measuremen t
3562A
2-1.
by pressing the
IS
the default selection.
select STABLE (MEAN) averaging.
,
Frequency Response Measurements with Linear Resolution
Figure 2·1
9