Ceyear 4051 Series, User Manual

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Appendix
Appendix A Terminology
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Detection mode
It is a way of processing before analog information is digitalized and saved in the memory and serves mainly
as a method of display detection for signal energy. It includes normal, Peak, negative peak, sample, and
average modes.
Speed factor
It refers to the numeric unit represented by each grid on vertical axis scale of the screen.
Zero Span
The sweep LO of the signal/spectrum analyzer is kept fixed to certain frequency, which means there is no LO
sweep operation (span = 0). When the span is set as zero, the signal/spectrum analyzer becomes a fixed-tuned
receiver whose bandwidth is the resolution bandwidth.
Drift
The LO frequency changes when the sweep voltage changes, resulting in the signal position changing slowly
on the screen. In case of drift, readjustment may be required, but the frequency resolution will not be
compromised.
Frequency response
The frequency response refers to the change of the amplitude along with that of the frequency within the
specified frequency range, namely the dependency between the amplitude and the frequency. The frequency
response is divided into absolute and relative frequency response. The absolute frequency response refers to
the amplitude offset of other frequency points when the signal amplitude of certain frequency point has been
taken as the reference within a given frequency range. Also known as the frequency response flatness, the
relative frequency response indicates the difference between the maximum signal amplitude and the minimum
amplitude or ±1/2 of such difference within certain band or the entire frequency range.
Marker
It refers to the visible indicating cursor placed at any point of the screen trace and can use numbers to display
absolute values of frequency and amplitude on traces on markers. Active markers refer to those on the traces
that are capable of being directly moved via control keys or remote control commands on the front panel.
Span
The difference between the start frequency and the stop frequency of the signal/spectrum analyzer. The
frequency span setting defines the scale of the horizontal axis of the screen of the signal/spectrum analyzer.
Frequency range
When the specified performance conditions are met, the signal/spectrum analyzer can measure the range
between the lowest frequency and the highest frequency. The frequency range and relevant band division
should be specified in the product specifications.
frequency accuracy
The degree of closeness between the measured frequency display value and the actual value. It is divided into
absolute and relative accuracy, in which the absolute accuracy refers to the actual size of read-out frequency
error and the relative accuracy refers to the ratio of the read-out frequency error against the ideal frequency
value.
Frequency stability
It refers to the extent of the signal frequency remaining unchanged in short term or long term. The short-term
frequency stability can be expressed with residual frequency modulation or phase noise. The long-term
frequency stability can be expressed with aging rate.