I n t r o d u c t i o n t o t h e H M 8 1 2 3 o p e r a t i o n
3 Introduction to the HM8123 operation
First time operation
Please observe the following hints especially during first time
operation:
–
This instrument has a wide-range power supply designed
for 115 to 230 V, 50/60 Hz ±10 %, i.e. it will operate from 105
to 254 V.
–
This instrument may only be connected to a wall outlet with
a three-conductor safety ground terminal or to an isolation
transformer of safety class 2.
–
There are two fuses inside of the instrument which are not
serviceable by the customer.
–
There are no visible damages to the instrument.
– There are no loose parts floating around inside.
Switch-on
After pressing the red POWER pushbutton
show „3 GHz counter Hameg HM8123" and the current software
version installed, e.g. 1.03. During initialization the HM8123 will
automatically load the configuration stored in memory 0.
4 Operation of the HM8123
4.1
Display
The display will show the actual measurement function, the
result and the reference source (internal or external).
FREQUENCY A:
10.000000 MHz
FREQUENCY A:
Pressing the HOLD
button will activate the Hold function, the
10.000000 MHz
FREQUENCY A:
pushbutton
will light up. The present result will be frozen. The
Hold function will be deactivated by pressing the button again or
10.000000 MHz
by selecting another function. The pushbutton light will be off.
HOLD
FREQUENCY A:
10.000000 MHz
FREQUENCY A:
HOLD
–10.000 kHz
FREQUENCY A:
REF: 100.000000 MHz
10.000000 MHz
By pressing the pushbutton OFFSET
FREQUENCY A:
be activated, the pushbutton OFFSET
mode the present result will be taken as the reference value
–10.000 kHz
and indicated in the display (e.g. REF: 100.000000 MHz). For all
REF: 100.000000 MHz
subsequent measurements this value will subtracted from the
FREQUENCY A:
result, the difference will be displayed.
10.000000 MHz
The following picture shows the display for a reference fre-
HOLD
quency of 100 MHz and a measured frequency of 99.99 MHz.
FREQUENCY A:
–10.000 kHz
REF: 100.000000 MHz
24
Subject to change without notice
the display will
Ref: INT
Ref: INT
Ref: INT
Ref: INT
Ref: INT
the Offset function will
will light up. In this
Ref: INT
Ref: INT
Ref: INT
Ref: INT
4.2
Measurement functions
All measurement function are called by the function keys
. The selected function key will light up. The function selected
will also be shown in the first line of the display.
A
B
C
D
G
H
I
FREQ A,
FREQ B,
FREQ C
Frequency measurement of the signal connected to the channel
selected. The frequency range of channels A
to 200 MHz and of channel it is 100 MHz to 3 GHz.
A high input sensitivity is not always desirable for frequency
measurements , as the counter will become increasingly sen-
sitive to noise on the signal. Hence frequency measurements
should be made using as much attenuation as possible
. Any dc content of a signal should be blocked by turning the
DC pushbutton
light off. DC coupling, however, is necessary
at frequencies below appr. 10 Hz (Pushbutton DC
case a low frequency signal is superimposed by high frequency
noise select the low pass filter LP 50 kHz .
PER A
Period measurement of the channel A signal.
WIDTH A
Measurement of the pulse width of the channel A signal.
Accuracy: 0.4% at squarewave (1 MHz)
A : B
Measurement of the frequency ratio of signals connected to
channels A
and B
. A ratio measurement is useful, for
instance, for calibration of oscillators with odd frequency. The
higher frequency should be applied to input A
highest resolution possible.
DUTY A
Measurement of the duty cycle of the channel A signal.
Accuracy: 0.4% at squarewave (1 MHz)
TI AB
In this mode Time Interval the time difference between a signal
on channel A
(start pulse) and a signal on channel B
pulse) will be measured.
TI avg AB
Measurement of the average of the time interval AB.
Phase AB.
Measurement of the phase difference between signals A and B.
RPM A
Measurement of the rpm (revolutions per minute) of a signal on
channel A
(e.g.rpm measurement using an optical sensor.)
The number of pulses per revolution has to be selected in the
menu (1 to 256 available).
E
F
K
L
M
and B
is DC
and
lighted). In
to achieve the
(stop
to