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AM
Using The Instrument 3-38
7. Select the Sweep State option
8. Rotate the dial clockwise to turn the Sweep function ON
9. Select and press the Sweep Time parameter
10. Move the cursor below the digit you want to change and rotate
the dial to adjust the Sweep Time parameter to 10ms.
11. Select and press the Stop parameter
12. Move the cursor below the digit you want to change and rotate
the dial to adjust the Sweep Stop parameter to 2.5MS/s
If you did not make any programming errors, the front panel outputs
will generate linearly swept waveforms from 100 Hz to 25 KHz in 10
ms.
We'll now check the results at the rear-panel sine output connector
and compare what we get there to what we see on the front panel.
Remove the cable from the main output connector and connect to
the rear-panel SINE OUT connector. Here is what you should
expect to see when you check this output:
1.
Waveform is sinewave having fixed amplitude level of 1V
into 50Ω.
2.
Sine waveform sweeps from 10 KHz to 2.5 MHz in 10
ms. Sweep step is linear.
Amplitude modulation, unlike frequency modulation is not digital.
Modulating waveform must be applied to a rear-panel connector to
modulate the LW120 outputs. Amplitude modulation control is
separate for each channel, so you can amplitude modulate one
channel without affecting the other.
Before using the AM function, you should get yourself familiar with
some of the terms:
Carrier – This term define the signal and its properties as are
available at the output connectors and without external intervention.
The carrier signal could be any type and shape that the LW120 can
generate.
Carrier Frequency – This term defines the frequency of the carrier
waveform. In standard waveforms mode, the frequency of the
waveform is displayed after you press the FREQUENCY button. In
arbitrary waveforms mode, the frequency of the output waveform is
derived from the sample clock frequency and the number of points
used to generate the active waveform segment.
Envelope Waveform – The carrier signal is modulated with an
external signal. This signal is referred to as the envelope waveform.
This waveform is applied to the AM IN connector and must have
specific amplitude to modulate the LW120 correctly
Envelope Frequency – This term defines the frequency of the
User Manual LW120
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