Subject to change without notice
19
O p e r a t i o n o f t h e H M 8 0 3 7
Operation of the HM8037
Frequency adjustment
The coarse adjustment is performed with the range
switch FREQUENCE
divided into four decades.
The desired frequency is selected by turning the
VARIABLE control
. The selected frequ ency
appears on the 3-digit display
. Compared to knob
sca les, this display has a much higher resolution.
The Hz and kHz range indicators are integrated into
the dis play panel.
Output amplitude and
signal connection
The adaptation in decade steps to the desired
amplitude range is performed by useing the two
attenuators
with –20 dB each, which are ac-
tivated by pushbuttons. Including the con tinuously
adjustable AMPL. control
, the maximum
attenu ation amounts to 60 dB. With the maximum
amplitude of 1.75 V, the minimum signal voltage to
be supplied is about 1.75 mV.
These values are obtained when the generator
output is terminated with 600 Ω. In the open-
circuit condition, the available signal amplitude
is about twice as high. Therefore the maximum
output voltage at the output socket is specifi ed with
10 V
pp
. For inter connecting with other equipment,
only high quality coaxial cables should be used,
e.g. HZ34. It should be noted that the terminating
resistor used must dissipate the corresponding
effective power.
Synchronous output
The SYNC. OUTPUT
of the HM8037 module
delivers a sinewave signal with a constant am-
plitude of about 2 V
pp
, which is in-phase with the
output signal at OUTPUT 600 Ω
. Any change of
the amplitude control or output signal attenuator
settings will not infl uence the synchronous output
voltage. The output is short-circuit-proof. It has an
impedance of approx. 1 kΩ and the same ground
reference as OUTPUT 600 Ω
. The synchronous
output signal is excellently suited for triggering
oscilloscopes or driving further measuring equip-
ment. This is especially favourable, if signals with
particularly low amplitude supplied by OUTPUT
600 Ω
are used.
Floating Operation
The HM8037 module output is isolated against the
chassis (protective earth) if pushbutton
is
pressed; i.e. the signal return line (low potential)
is not connected to the chassis ground. Hum and
noise voltages introduced via the chassis are
suppressed due to this confi guration. If
is
released the mainframe ser ves to con nect the
module to protective earth.
Warning! The maximum voltage (com-
mon mode sig nal) between the isolated
low potential line and the chassis
(protective earth) should not exceed
42 V. Any higher voltage will destroy the
output amplifi er and be hazar dous to
the operator.
External offset
Attention! Do not apply any DC voltage
to the out put sockets of the HM8037
Module!
If the output of the HM8037 module comes into
contact with components of the circuit under
test, which are carrying DC voltage (i.e. if the
load resistor is superposed with a DC voltage),
an isolating capacitor of appropriate dielectric
strength should be connected in series with the
output line of the generator. The capacitance of
this isolating capacitor should be selected in such
Distortion factor as a function of frequency
f[Hz]
