Operation Of The Hm8123; First Time Operation; Switch-On; Display - Hameg HM8123 Benutzerhandbuch

Operation of the HM8123

3 Operation of the
HM8123
3.1

First time operation

Please note the following hints 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.
3.2

Switch-on

After pressing the red POWER pushbutton
will show „3 GHz counter Hameg HM8123" and the cur-
rent software version installed, e.g. 1.03. During initializa-
tion the HM8123 will automatically load the configuration
stored in memory 0.
3.3

Display

The display will show the actual measurement function,
the result and the reference source (internal or external).
FREQUENCY A:
10.000000 MHz
Pressing the HOLD button will activate the Hold func-
27
tion, the pushbutton will light up. The present result will FREQUENCY A:
FREQUENCY A:
be frozen. The Hold function will be deactivated by pres-
10.000000 MHz
10.000000 MHz
sing the button again or by selecting another function. The
HOLD
pushbutton light will be off.
FREQUENCY A: FREQUENCY A:
10.000000 MHz –10.000 kHz
HOLD REF: 100.000000 MHz
By pressing the pushbutton OFFSET
FREQUENCY A:
tion will be activated, the pushbutton OFFSET
FREQUENCY A:
10.000000 MHz
light up. In this mode the present result will be taken as
–10.000 kHz
the reference value and indicated in the display (e.g. REF:
REF: 100.000000 MHz
100.000000 MHz). For all subsequent measurements this
value will subtracted from the result, the difference will be
FREQUENCY A:
displayed.
10.000000 MHz
The following picture shows the display for a reference fre-
HOLD
quency of 100 MHz.
FREQUENCY A:
–10.000 kHz
REF: 100.000000 MHz
22
the display
1
Ref: INT
Ref: INT
Ref: INT
Ref: INT Ref: INT
the Offset func-
29
will
29
Ref: INT
Ref: INT
Ref: INT
Ref: INT
3.4

Measurement functions

All measurement function are called by the function keys
to . The selected function key will light up. The func-
A M
tion selected will also be shown in the first line of the
display.
A B C
G H
Fig. 3.1: The function keys and their meaning
FREQ A, FREQ B,
A B
Frequency measurement of the signal connected to the
channel selected. The frequency range of channels A
and B is DC to 200 MHz and of channel C is 100 MHz to
22
3 GHz.
A high input sensitivity is not always desirable for fre-
quency measurements, as the counter will become incre-
asingly sensitive to noise on the signal. Hence frequency
measurements should be made using as much attenua-
tion as possible and
13 16
should be blocked by turning the DC pushbutton
off. DC coupling, however, is necessary at frequencies be-
low approx. 10 Hz (DC Pushbutton lighted). In 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.
D
Measurement of the pulse width of the
E WIDTH A :
channel A signal. Accuracy: 0.4% at squarewave (1 MHz)
A : B : Measurement of the frequency ratio of signals
F
connected to channels A
ment is useful, for instance, for calibration of oscillators
with odd frequency. The higher frequency should be ap-
plied to INPUT A to achieve the highest resolution
20
possible.
Measurement of the duty cycle of the chan-
DUTY A :
G
nel A signal. Accuracy: 0.4% at squarewave (1 MHz)
I In this mode Time Interval the time difference
TI A B :
H
between a signal on channel A
on channel B 22 (stop pulse) will be measured.
A B Measurement of the average of the time
I TI avg :
interval A B.
D E F
I K L M
FREQ C
C
. Any dc content of a signal
.
18
20 and B 22 . A ratio measure-
(start pulse) and a signal
20
20
14 light