29
Subject to change without notice
O p e r a t i n g t h e i n s t r u m e n t
Indroduction of the HM8135
First time operation
Before starting the instrument the fi rst time, please check the
following:
– The line voltage indicated on the rear panel corresponds
to the available line voltage, also, the correct fuses for this
line voltage are installed. The fuses are contained in the line
voltage connector housing.
– The connection to the mains is either by plugging into a
socket with safety ground terminal or via an isolation trans-
former of protection class II.
– No visible damage to the instrument.
– No visible damage to the line cord.
– No loose parts fl oating around in the instrument.
Switch-on
After depressing the red power key
, the display of the HM8135
will successively show the following messages:
– the type (SYNTHESIZER) and the version of the instrument
(HM8135)
-
the self-test messages ”RAM checking“ and ”DDS loading“
(RAM = Random Acess Memory; DDS = Direct Digital Syn-
thesis)
– Optional interface:
SECOND COM INTERFACE: NONE, RS-232 (HO890),
IEEE488 (HO880), USB (HO870)
– Optional OCXO:
FREQUENCY
REFERENCE
OCXO
OPTION
>
NO (YES)
– the reference soure in progress (internal or external):
FREQUENCY
REFERENCE
Internal
(External)
After switch-on the HM8135 has the confi guration stored in
the confi guration memory 0. The output signal is disabled after
switch-on by default.
Factory confi guration
At delivery the instrument is adjusted for a basic set-up:
– Frequency:
3000
MHz
– Level:
+7
dBm
– No
modulation
– Reference
source:
internal
– Fmod: 1 kHz, Shape: sine (for all modulations)
– Dev: 20 kHz (FM), Dev: 1 rad (PM) , Depth: 50% (AM)
– Contrast:
maximum
– Sound
indicator:
none
– Interface parameters: 4800 baud / 1 stopbit / 8 data bits
This basic adjustment can be recalled at any time as follows:
– Switch off the unit.
– Switch on the unit and hold the ESC key until you hear se-
veral beeps. This procedure is especially suited in case of
doubt.
STOP
Caution:
The 10 memories storing confi gurations are erased
and replaced by the previous basic adjustments.
Operating the instrument
Main display
This display shows the frequency and the level of the RF output
signal and the reference in use (INTernal or EXTernal). If no
modulation (AM, FM, PM) is turned on, the display shows:
Moreover, it contains some modulation parameters (for example
in case of AM modulation, shape SQR and Fmod = 1 kHz).
This state is left by pressing one of the function keys
or the
MENU key
.
ESC key
The ESC key
allows the user to return to the main display,
to unselect the current function
or to cancel the numeric
keypad input.
Setting parameters
Once a parameter is selected (for example FREQ.) with a func-
tion key
, a new value for this parameter can be entered from
the data keypad
or modifi ed by the digital rotary
or by
one of the four context sensitive keys
below the displayed
marks – and + .
The operation of the data keypad is conventional. Depress suc-
cessively the numeric keys representing the parameter value
and at the end the unit key (for example MHz or dBm). Note that
it is not necessary to enter any leading zeros. The instrument
always displays at least one digit on the left of the comma.
Before the unit selection, it is possible to cancel the value by
pressing the ESC key
. In this case the previous value is
restored.
The encoder
modifi es the value of the digit underlined by the
cursor (if the cursor underlines a blank position, it is considered
as 0). The cursor is shifted to another position by pressing the
keys below
the 2 arrows
and the value can be increased or
decreased by operating – or +. An unproper value is announ-
ced by a warning message and the sound indicator if activated
(except for out of range of encoder
and steps).
Selecting frequency
After pressing the FREQ. key
, the display shows:
A new value can be entered from the data keypad
or mo-
difi ed by the digital rotary
or by one of the four context
sensitive keys
. For more details, refer to the paragraph
”Setting parameters“. The frequency range is 1 Hz to 1200 MHz.
