Ceyear 4051 Series, User Manual

Page: 72 / 751

4. Operating Instruction
4.1 Function operation guide
58
4.1.2.2 Settings of frequency and span/X Axis
The 【 Frequency 】 key and 【 Span/X Axis 】 key can be used to set the range displayed by X Axis in the
current active window of Series Signal Analyzer. Under non-zero span (greater than zero), the active window
of spectrum analysis mode usually displays the signal spectrum trace with X Axis as frequency axis; the
frequency measurement range can be set through the
【 Frequency 】 key and 【 Span/X Axis 】 on the front
panel; under zero span (equals to zero), it displays the trace of signal frequency changing over time with X
Axis as time axis. Only the span can be changed should corresponding soft menu of
【
Span/X Axis
】
be
operated.
1) Parameter description of 【 Frequency 】 key
Frequency range (frequency measurement range) refers to the display range of frequency axis of Series Signal
Analyzer. The frequency range is displayed in the information display area under screen with two ways
including center frequency value and span value or start frequency value and stop frequency value. The
parameters corresponding to
【
Frequency
】
key include[Center Freq], [Start Freq],[Stop Freq],[CF
Step],[Freq Offset], [Auto Tune] and [Signal Track].
 [Center Freq] is used to set and indicate the frequency value in the center of measurement display
window of Series Signal Analyzer;
 [Freq Freq] is used to set and indicate the frequency value in the leftmost position of measurement
display window of Series Signal Analyzer;
 [Stop Freq] is used to set and indicate the frequency value in the rightmost position of measurement
display window of Series Signal Analyzer;
 [CF Step] is used to set and indicate the frequency step size when the center frequency, start frequency
and stop frequency are changed through Up/Down key on the front panel;
 [Freq Offset] is used to set and indicate the correction value of frequency range of information display
area;
 After the [Auto Tune] is pressed, the Series Signal Analyzer will automatically optimize and set the
frequency measurement range and display range of Y Axis based on the signal characteristics. For the
specific setting methods and operation guidance of auto optimization, please refer to chapter ―4.1.2.7
Parameter setting of coupling and auto‖ herein;
 [Signal Track] is used to track and measure the drift signal, by which the center frequency of Series
Signal Analyzer can be automatically tuned for the maximum peak frequency of input port signal. For
measurement methods of drift signal, please refer to chapter ―4.2.8 Drift signal measurement‖ herein.
2) Parameter description of
【
Span/X Axis
】
key
Span refers to difference between start frequency and stop frequency measured by Series Signal Analyzer.
Under spectrum analysis mode, the parameters corresponding to
【
Span/X Axis
】
key on the front panel
include [Span], [Full Span], [Zero Span] and [Last Span], which are used to set the frequency range measured
by Series Signal Analyzer, provided that the center frequency remains unchanged. Differences may exist in
other modes, please refer to relevant manual for specific operations.
[Full Span] is used to set the frequency measurement range as maximum frequency range. It should be noted
that the center frequency will automatically change to 1/2 of nominal maximum upper limit frequency of
analyzer. This setting is of great use for observing the signals in the entire frequency measurement range.
[Zero Span] is used to set the span as 0 Hz, then the X Axis will change to time axis and the length of time
will automatically become the sweep time of current Series Signal Analyzer.
[Last Span] is used to set the span as the value set last time. This function can help the user quickly switch the
detail measurement under full span measurement and narrower span.
3) How to set frequency measurement range