Introduction In The Operation Of The Hm8123; Operation Of The Hm8123; Display; Measurement Functions - Rohde & Schwarz Hameg HM8123 Handbuch

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
Introduction to the HM8123 operation
First time operation
Please observe the following hints especially during fi rst 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 fl oating 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 confi guration stored in memory 0.

Operation of the HM8123

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 function, the
pushbutton will light up. The present result will be frozen.
The Hold function will be deactivated by pressing the button
again or by selecting another function. The pushbutton light
will be off.
FREQUENCY A:
10.000000 MHz
HOLD
By pressing the pushbutton OFFSET
be activated, the pushbutton OFFSET
mode the present result will be taken as the reference value
and indicated in the display (e.g. REF: 100.000000 MHz). For all
subsequent measurements this value will subtracted from the
result, the difference will be displayed.
The following picture shows the display for a reference frequen-
cy 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
the Offset function will
will light up. In this
Ref: INT

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 fi rst line of the display.
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 fi lter 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 A B
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 A B
Measurement of the average of the time interval A B.
Phase A B.
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).
to
and B is DC
and
lighted). In
.
to achieve the
(stop