Measure Menu; Auto Tune; Receiver-Mode; Fig. 6.14: Calibration Menu Of The Vswr Wizard - Hameg HMS-X Benutzerhandbuch

Instrument functions

6 . 1 1 Measure Menu

The key MEAS opens the measure menu with different op-
tions. The softkey CF>RX opens the receiver mode tuned
to the actual center frequency. The softkey M1>RX opens
the receiver mode tuned to the actual frequency of marker
1. The softkey Reflection Cal starts the calibration wizard
of the reflection measurement.
To use the wizard the HAMEG VSWR bridge HZ547 is re-
commended. The VSWR bridge HZ547 allows the mea-
surement of the voltage standing wave ratio (VSWR) and
the reflection coefficient of 50 Ω devices. The frequency
range of the HZ547 is 100 kHz to 3 GHz.

Fig. 6.14: Calibration menu of the VSWR wizard

The HMS-X with activated TG option (HMS-TG / HV211)
guides the user through all steps of the reflection mea-
surement sequentially. Concerning the reflection mea-
surement you have to connect the VSWR measuring
bridge to the spectrum analyzer. The tracking generator
(TG) will be switched on automatically, if you don't have
activated it already.
The wizard for the reflection measurement is only available with
the TG option HMS-TG resp. HV211.
The signal source (tracking generator / OUTPUT) needs
to be connected to the IN connector of the VSWR bridge.
Dispaly of measurement time (MT)
Display of reference level
(Ref) and attenuator(Att)
Display of frequency
and amplitude
Fig. 6.15:
Display layout in receiver mode
62
The OUT terminal of the bridge needs to be connected to
the input (INPUT) of the spectrum analyzer. At first, you
have to let the DUT terminal open which equals total mis-
match. Afterwards, a short calibration measurement will
perform. A review of these two signals with the trace math
will illustrate that both measurements are phase shifted by
180°. The white waveform describes the open calibration
measurement, the yellow waveform describes the short
calibration measurement. Based on the trace math (Trace -
Mem) a total compensation of the measurement deviation
is archieved and the deviation of the device under test to a
zero measurement will be shown.
Before starting the wizard you have to select a trace detec-
tor. The selected detector will be used during the measurement
automatically.
The measured reflected energy by the spectrum analyzer
which will now indicate the algebraic difference between
both measurements in dB which is the desired return loss.
Once the return loss has been determined use the table on
the VSWR measuring bridge to read the Reflection Coef-
ficient and the VSWR. More detailed information about the
VSWR measuring bridge HZ547 you can find in the appro-
priate manual which can be downloaded from our home-
page www.hameg.com.

6 . 1 2 Auto Tune

By pushing the AUTO TUNE key the instrument performs a
scan at full span, locate the maximum peak value and cen-
ter it in combination with applicable RBW and span set-
tings on the display. This is a comfort function to assist the
user. The closer the signal level is located to the general
noise floor, the harder the peak is detectable for the AUTO
TUNE algorithm. Therefore, it is possible that the settings
must be slightly adjusted by the user. This process can
hold up few seconds.

6 . 1 3 Receiver-Mode

By pushing the MODE key a setting menu will be opened
which allows to switch between sweep mode (analyzer
Display of bandwidth
Softkey inscription in
receiver mode