Ceyear 4051 Series, User Manual

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4. Operating Instruction
4.2 Advanced operation guide
120
 Press 【 Span/X Axis 】 , [Span] and enter 500kHz.
 Press
【
BW
】
, [Res BW Auto
Man
] and enter 30kHz;
 Press
【
Sweep
】
, [Sweep Time Auto
Man
] and enter 20 ms.
Step 3. set Y axis scale unit as volt:
 Press 【 Amplitude/Y Axis 】 , [MORE 1/2 ▶ ], [Y Axis Unit ▶ ] and [V].
Step 4. place the signal peak near the reference level:
 Press
【
Amplitude/Y Axis
】
, [RefLevel] and turn the knob to adjust the reference level.
Step 5. change Y axis display scale to linear scale:
 Press 【 Amplitude/Y Axis 】 and [Scale Type Log Line].
Step 6. set the analyzer as zero frequency span for time domain measurement:

Press Span/X Axis] and [Zero Span].
 Press 【 Sweep 】 , [Sweep Time] and enter 5 ms.
Step 7. use video trigger function to stabilize display trace:
 Press
【
Trig
】
and [Video
▶
].
Since the modulation is stable, sweep operation can be triggered on the waveform via video trigger to stabilize
trace, which process is similar to the oscilloscope, as shown in Fig. 4.35. If the video trigger level is set too
high or too low in video trigger mode, the sweep will stop. In this case, the knob on the front panel can be
used to adjust the video trigger level until the sweep resumes.
Step 8. measure amplitude modulation speed with delta maker:
 Press 【 Peak Search 】 and [Delta Marker].
 Press 【 Peak Search 】 , [Next Pk Left] or [Next Pk Right], place the marker at the peak and then use the
delta marker to measure the time difference between peaks.
During measurement, it should be ensured that the delta marker is on the nearby peak as shown in Fig. 4.35.
The modulation speed of the FM or AM signal can be derived by dividing 1 with the time difference between
adjacent peaks.
In this example, AM signal speed is obtained by calculating the time difference between AM signal time
domain peaks. In order to measure more accurately, the center frequency can be placed on the steep point at
the edge of the AM signal and set the analyzer as zero frequency span and sweep time two times of the
modulation speed so as to increase sweep points for the purpose of improving measurement accuracy.