Tus neeg siv phau ntawv

Tel: [phone] Email: [e-mail]
www.salukitec.com
58
Total signal harmonic distortion percentage is also subject to frequent test. In order to test such parameter,
amplitude of each harmonic should be tested with linear unit (such as volt) rather than relative unit dBc. Press
[Amplitude], [Units] and [Volt] to set the amplitude unit as volt. The measured signal amplitude can be applied in the
following equation to calculate the total harmonic distortion:
     
%
100
distortion harmonic Total
1
22
3
2
2
A
AAA
n


Where:
A
1
- refers to fundamental wave amplitude (V)
A
2
- refers to second harmonic amplitude (V)
A
3
- refers to third harmonic amplitude (V)
A
n
refers to n
th
harmonic amplitude (V)
If the signal amplitude is carefully measured as shown in the above example, the obtained harmonic distortion
percentage is accurate.
8 Pulse RF signal measurement
1) Definition of pulse RF signal
The pulse RF signal refers to a RF pulse string of the same repetition frequency and constant pulse width, shape
and amplitude. This section introduces several methods of measuring pulse RF signal parameters, including how to
measure the center frequency, pulse width and pulse repetition frequency. In addition, the measurement of peak
pulse power is also discussed.
The resolution bandwidth has great influence on pulse RF signal measurement. You must understand the
relationship between the resolution bandwidth and pulse repetition frequency. If the resolution bandwidth is
narrower than the pulse repetition frequency, only individual frequency components of the pulse RF signal will
appear on the screen. This is known as the narrow band mode. The mode in which the resolution bandwidth is
broader than the pulse repetition frequency is known as the broad band mode. In this case, you can see the
spectrum envelope formed by pulse segments that are equalized by the tested pulse repetition frequency.
2) Center frequency, side lobe ratio and pulse width measurement of pulse RF signal
a) Set the output signal of the signal generator: