With 5MHz to 3.3GHz tracking generator Applications Frequency characteristics measurement of electronic component/circuit and return loss measurement
Three measurement modes shown below are available.
The troublesome setting for EMI test is unnecessary because
the parameters corresponding to measurement mode are
automatically preset
| Measurement Mode | Function Key | Preset |
|---|---|---|
| Normal Measurement | NORM (F1) | Presets initial parameters of normal mode |
| EMI-C | F2 | Presets initial parameters of conducted emission mode |
| EMI-R | F3 | Presets initial parameters of radiated emission mode |
MSA438E has three detection modes of PK (peak), QP (quasi-peak) and AV
(average). As for the datection level, the relational expression of PK≧ QP≧
AV is valid as shown in the figure below. Additionally, PK=QP=AV is correct
in case of a narrowband signal like CW wave
VSWR bridge MVS300 (option) connected to TG OUT and RF IN of
MSA438TG enables the return loss measurement. The measured frequency
range is from 5MHz to 3GHz.
Additionally, the calibration of the return loss 0dB is done by using the
NORMALIZING function.
The PK detection is achieved by setting the measurement mode to normal
measurement, the detection mode to positive peak and the calculation function
to MaxHold. By the way, a signal of time width 200ns or more is detected by
positive peak detector because the sampling speed of A/D converter is 5MS/s.
When observing a disturbance noise, the PK detection enables the fast sweep
because its time constant is much smaller than QP or AV.
Therefore, it is convenient to use the PK detection when narrowing the
disturbance noise spectrums out of specification down to small number
Although the spectrum is displayed by 501 points on the horizontal axis of the
screen of MSA438E, it is captured by 1001 points per sweep in the
instrument. All of these 1001 points are transferred to a personal computer and
displayed on the PC screen after processed by PC software MAS430. The
image, therefore, becomes clearer.
CISPR provides that the radiated and conducted emissions should be
measured with RBW filters of 9kHz and 120kHz respectively. The bandwidth
is defined as 6dB width. MSA438E also has five RBW filters besides these
two filters, whose bandwidths at 3dB are 3kHz, 30kHz, 300kHz, 1MHz and
3MHz.
94, Electronic Complex, Pardesipura, Indore-452010, Madhya Pradesh, India.
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