Frequency; Pulse Width; Amplitude; Offset - Hameg HM8130 Handbuch

Figure 4: Arbitrary signal controlled by trigger signal

Frequency

The frequency of the output signal is set by using the digital
rotary dial or the decade range switches
dial has an acceleration-dependent resolution. Turning it
slowly will increment or decrement the value of the smallest
digit, but turning it faster advances through the frequency
range in larger steps. Before the frequency can be set, the
FREQ. button must be pressed to activate this parameter.

Pulse width

The pulse width for the pulse function is changed using the
rotary dial or the decade range switches
the PULSE button to enable this parameter. After the pulse
function has been selected, the current pulse duration is shown
in the display. The displayed value refers to the positive pulse
duration. Only pulse durations within the permissible range
for the selected frequency are displayed. Attempts to set a
time value outside of this range will cause a beep and the entry
will not be accepted. The maximum pulse width is defined by
the following formula: pulse width = 0.8 / frequency. If the
INVERT button pressed, negative pulses are generated. In
this case, the time for the negative pulse width is shown in the
display. If the sweep function is enabled, the pulse width is
determined by the start or stop frequency whichever is higher.

Amplitude

The output amplitude is basically changed in the same way as
the two parameters just described. The value shown in the
display is the peak-to-peak voltage for the output without
load. Pulses start at the zero crossing and are either positive
or negative, depending on whether the INVERT function is
activated (the INVERT-LED
signal amplitude – in reference to the baseline – is then shown
in the display.
The ranges for setting the output amplitude are as follows:
Without load
Range1 2.1 V to 20 V
Range2 0.21 V to 2.0 V
Range3 20 mV to 200 mV
The decade range switches ÷10/ * and x10/
to manually switch among these ranges. The rotary dial
used to vary the amplitude within each range, with the next-
. The rotary
. First press
lights). The positive or negative
into 50 Ω
1.05 V to 10 V
0.105 V to 1 V
10 mV to 100 mV
can be used
O p e r a t i o n o f t h e H M 8 1 3 0
highest or next-lowest range being automatically switched to
when the limits of the current range are exceeded. When the
output is terminated with 50 the values shown in the display
must be divided by 2 to get the correct value. If an offset voltage
is added, then it may not be in a higher range than the
amplitude setting.

Offset

The output signal can be superimposed with a negative or
positive DC offset.This function is enabled by pressing the
OFFSET button and the corresponding LED lights up to
indicate that the offset is active. The rotary dial
conjunction with the INVERT button
buttons in the same way as already explained to set the value
for the offset voltage.
The maximum possible offset voltages are as follows:
Range1 ± 7.5 V
Range2 ± 0.75 V
Range3 ± 75 mV
The offset voltage must be in the same range as the value
selected for the amplitude of the output signal. An offset of 5
V cannot be used for a signal voltage of 20 mV. Within a given
range, the offset voltage can be varied continuously from
negative to positive values. The same conditions apply for the
use of the offset with the sweep function.

Signal output

The signal output of the HM8130 has an
impedance of 50 and can be switched
on and off using the OUTPUT ON button
. If an offset voltage is being used, it
is switched on and off by the OFFSET ON
button . A LED lights up to indicate
that the output is active. The INVERT
button is used to reverse the polarity
of the output signal. The output is short
– circuit – proof and protected against
reverse voltages (AC and DC) for a short
time (approx. 15 sec.).

Sweep mode

Sweep mode can be additionally enabled to supplement the
operating modes continuous, gated and triggered. It is
activated by pressing the SWEEP ON button
state is indicated by the corresponding LED. The parameters
sweep time, start frequency and stop frequency can be set
independently of each other. This is done in the same way as
the setting of the "normal" frequency. The parameters can
also be changed while sweep mode is active (online) and the
changes become visible immediately. In this case the sweep
is
is used in
and the decade range
and the active
23
Subject to change without notice