Operation - First Steps; Settings; Attn; Frequency Setting - Hameg Instruments Hm5012-2 Handbuch

Controls and readout
ZERO SPAN A B A AVERAGE
SAVE B M a x
SET
SPAN RECALL A - B LOCAL/PRINT
R M
SET
24 22 19
20 17
21 18
23
(24) ZERO SPAN - Pushbutton
Briefly depressing this pushbutton switches this mode
on or off. In the latter case the previously present SPAN is
restored.
In ZERO SPAN mode the readout shows „ZERO-SP"
instead of the SPAN setting. This mode enables
measurement on a discrete frequency that is determined
by the center frequency setting.
ZERO SPAN can also be switched of by depressing one of
the SPAN (22) pushbuttons.
(25) INPUT 50Ω Ω Ω Ω Ω - N socket
This is the 50Ω spectrum analyzer input. Without input
attenuation (0dB), applied input signals of ±25V DC or
+10dBm must not be exceeded. In combination with
40dB (maximum) input attenuation, the maximum allowed
input is 20dBm.
The outer contact is galvanically connected with the
protective earth connector via the chassis.
TRACKING GENERATOR
TEST SIGNAL
ON
Ω
OUTPUT 50 OUTPUT 50
28
(26) PHONE – Socket and VOL.-Control.
The phone jack is provided for the connection of
earphones with >8 Ohm impedance and a 3.5mm jack
plug. The volume can be varied with a screwdriver using
the VOL. control.
The signal at this socket originates from the AM
demodulator and eases the identification of signals. E.g.
If an antenna is connected to the spectrum analyzer input
in Zero Span mode, the instrument can be tuned to a
discrete transmitter frequency. Please consider that use
of this function must be within the limits of the law.
(27) TEST SIGNAL – BNC socket with pushbutton and
associated LED.
Even if the LED is not lit, the BNC socket serves always as
a broadband signal source with many spectra even though
the 48MHz signal is absent. It can be connected to the
spectrum analyzer input via a 50 Ohm cable and used for
function check of the input.
If the output is switched on (LED lit) a 48MHz signal with
a level of approx. –30dBm is additionally connected to
the test signal output. Please note „Test Signal Display"!
38
5dB/DIV
VBW
kHz
4
. H L D
dB
kHz
0
1000 10

RBW

20 AT TE N
120
9 30
40
14 12 13
16
15
INPUT 50
Push Long
+
ON
25
-
.
PHONE VOL
VDC
48MHz
max.
Ω
-30 dBm +10dBm
25
27
26
(28) TRACKING GENERATOR – N socket and OUTPUT
.
pushbutton with ON LED (HM5014-2 only).
0 dB
For protection of devices connected to the tracking
.
generator it is always in off condition after switching the
instrument on. This state is indicated by the letter „t"
displayed by the readout and the LED is not lit. Depressing
10
the pushbutton switches the tracking generator on, the
11
LED lights, and the readout now displays the capital letter
„T" in front of the tracking generator level. Depressing
the pushbutton once again switches the tracking
generator off.
A sine wave output signal is provided at the N socket with
a source impedance of 50 Ohm. The sine wave signal
frequency is always identical to the spectrum analyzer
receiving frequency.
PROBE POWER
(29) PROBE POWER
The jack has a diameter of 2.5mm and may be used only
for supply of HZ530 near field probes. The inner connector
(+6V) and outer connector (galvanically connected with
Protective Earth) can supply a maximum current of 100mA.
Operation – first steps

Settings:

Before an unknown signal is applied to the input of the
Ω
instrument, it should be verified that the DC component is
smaller than +/-25V and the signal level below +10 dBm.

ATTN:

ΙΙ ΙΙ
CAT CAT
As a protective measure the attenuation should initially be
set to 40 dB.

Frequency setting:

Set CENTER FREQ. to 500 MHz (C500MHz) and choose a span
of 1000 MHz (S1000MHz).

Vertical scaling:

For maximum display range choose 10dB/div scaling.
RBW (resolution bandwidth):
At the start of a measurement it is recommended to select
1000kHz (IF) bandwidth and to switch the video filter (VBW)
off.
If under these conditions only the noise band (frequency
base line) is visible the input attenuation can be reduced to
enable the measurement and display of lower signal levels.
Bear in mind that at full span, very narrow, high level signals
may low intensity and thus difficult to see, and should be
carefully sought before reducing attenuation. If the
frequency base line shifts to the top, this may be caused by
a high level spectra outside the measuring range. In any
case the attenuator setting must correspond to the biggest
input signal (not Zero-peak). The correct signal level is
achieved if the biggest signal („0 Hz" - 1000 MHz) just
touches the reference line. If the signal surpasses the
reference line, the attenuation must be increased, or an
external attenuator (of suitable power rating and
attenuation) must be used.
Operation – first steps
I n s t r u m e n t s
29
Subject to change without notice