Amplitude; Adjustment Of The Offset Voltage; Signal Output; Selection Of Phase-Angle - Hameg Instruments Hm8131-2 Handbuch

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Amplitude

By selecting "AMPL" [8] the signal amplitude is
adjustable via the key pad or the rotary control. The
selection is made as discussed in the section on "Para-
meter-Input".
The amplitude read from the display is the open-circuit
value. By loading the output with 50Ω, the output voltage
decreases to one-half of the displayed value.
The voltage units can be selected as peak-to-peak (Vpp)
or RMS values by pressing the pp/rms key. RMS values
are not applicable for the arbitrary function. The indicated
voltage does not consider any offset values.
The output voltage can be adjusted in three ranges
Open Circuit
Range 1 20.0 mVpp to 200 mVpp
Range 2 0.2Vpp to 2Vpp
Range 3 2Vpp to 20Vpp
If an offset voltage is applied the obtained output voltage
is limited to the saturation of the output stage. The
maximum obtainable output voltage will be 10Vp, 1Vp
or 0.1Vp according to the range selected.
If amplitude modulation is selected, the maximum
voltage in every range is limited to 50% of the standard
value. The maximum output voltage is limited to 10V.

Adjustment of the Offset Voltage

The offset voltage is a positive or negative DC voltage
that is superimposed on the signal voltage. The
adjustment is made in the same way as adjusting the
output voltage. By pressing the OFFS [8] key, the offset
voltage is adjusted via the key pad or the rotary control.
The maximum offset voltage is + 5V o.c. for amplitude
range 3.
Offset voltages ranges:
Range 1:
Range 2:
Range 3:
The maximum offset voltage is limited according to the
3 ranges. An offset voltage of 5V cannot be set, when
the lowest signal voltage range is selected. Within each
range the offset voltage is continuously variable between
32
50Ω Load
10mVpp to 100mVpp
0.1Vpp to 1Vpp
1Vpp to 10Vpp
±50mV
±0.5V
±5V
positive and negative values. Offset voltages lower than
10mV cannot be set.
An offset voltage cannot be superimposed to an AM
signal. If the offset function is not activated and an offset
voltage is selected which is larger than the signal
amplitude range, the offset is ignored. For the use of
offset during sweep the same is applicable. The
presence of offset voltage is indicated with an LED [7].

Signal Output

The signal output [12] of the HM8131-2 has an impedance
of 50Ω. It can be switched ON or OFF by use of the
Output [13] key. The same holds for the offset voltage.
The activated output is indicated by an LED. If the output
is Off, the circuit is open.
The attenuation of the output signal is up to -60dB
at 1MHz. Due to stray capacitance the attenuation
decreases slightly with higher frequencies.
The output circuit is short-circuit protected. The
maximum externally applied signal voltage shall
not exceed ±15V AC or DC for max. 30 sec..

Selection of Phase-Angle

The reference for the phase angle is the "Trig. Out"
connector located on the rear of the HM8131-2. The
output signal can be varied in phase with reference to
that signal from 0 to 359.9 degrees.
The phase-angle adjustment is made via the menu
"OPTIONS MENU 2" and by subsequent use of the key
pad or rotary control similar to the frequency and
amplitude adjustment. Acknowledgment of the
adjustment is made via the key "Deg".

Operation modes

The HM8131-2 has several different modes of operation.
Besides the standard free-running mode "Cnt" it provides
the single triggered "Trg" or gated "Gat" operation
possibilities. Selection of operation modes is made via
the menu. The initial mode on delivery is free-running.
The operation mode "Sync" enables the user to
synchronize several HM8131-2.
The operational modes are indicated in the LC-display to
the left of the frequency reading.
Subjest to change without notice