Hameg HM1008 Manual Download Page 40

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Subject to change without notice

32.1

CH1

If CH1 is selected only CH1 will be turned on, the mode is Yt. Also
the readout will only display the parameters of CH1. (sensitivity,
inverted/not inverted, coupling.)
Although CH2 will not appear in the readout it may be used e.g.
as a trigger input. Its controls are active but are not shown.

32.2

CH2

If CH2 is selected only CH2 will be active, it is Yt mode, and only
its parameters will be shown in the readout.
Although CH1 will not appear in the readout it may be used e.g.
as a trigger input. Its controls are active but are not shown.

32.3.1

DUAL trace alt./ chop

In dual trace mode both channels are turned on and the parame-
ters of both are shown in the readout. Between the sensitivity indi-
cations there is an indication whether alternate ”alt.“ or chopped
”chp“ mode is active. Normally, the mode will be automatically set
by the time base speed selection, but it may be directly set using
the function pushbutton. For time base speeds of 500 ms/cm to
500 μs/cm chopped will be used, from 200 μs/cm to 50 ns/cm
alternate. This refers to unmagniﬁ ed time bases.
Alternate is the preferred mode, at any time one channel is dis-
played for a full sweep, after each sweep the other channel has
its turn. At slow sweep speeds this will cause annoying ﬂ icker,
at still slower ones the channel switching becomes visible. Here,
the chopped mode steps in, both channels are switched at some
high frequency so they are both visible at any sweep speed.
This is, however, not appropriate for fast sweep speeds as the
switching may become visible and may interfere with the proper
signal display.

32.3.2

DUAL (DSO mode).

In DSO mode there is an a/d converter for each channel so both
are measured simultaneously. Hence no channel switching is
necessary and no information pertaining to it is shown.

32.4 ADD

In ADD mode the signals of both channels are algebraically
added and displayed as one sum signal. The Y position can be
changed with both position controls. If one channel is inverted
the difference will be displayed. Only one ”0 V“ symbol will
be shown in the readout. The ADD mode will be indicated by
placing a ”+“ symbol between the sensitivity indications of both
channels. In DSO mode ”1+2“ will be displayed at the end of
the trace.
Please note that the results of cursor measurements in this
mode will only be correct if the sensitivities of both channels are
identical, otherwise the readout will show ”CH1

CH2“.

C o n t r o l s a n d R e a d o u t

Automatic voltage measurements can not be performed in ADD
mode. The readout will show ”n/a“ = not available.

As the trigger signals are taken off the inputs and not from the
added signal there is no true reference for the trigger point
symbol, the symbol will thus be switched off in analog mode.
However, the LEVEL A/B control

is active.

In DSO mode a trigger time symbol is displayed one line above
the lowest graticule line to indicate the trigger time position
along the signal and thus can only be moved horizontally.

32.5 XY

In this mode CH1 will move the trace in X direction, hence the
readout will show ”CHX..“, CH2 will move the trace in Y direction,
hence ”CHY...“ will be shown rather than ”CH2...“.

As the time bases are not involved in XY no time base related
information will be shown. Also the trigger circuits are disabled
so no trigger information is shown, either.

The magniﬁ er MAG x10

is disabled. The ”0-Volt“ symbols

will be shown as triangles at the right hand graticule and above
the sensitivities.

Both the HORIZONTAL

or the POSITION 1

knobs will

move the trace horizontally. The Y position is controlled by the
POSITION 2 knob.

32.5.1

Analog mode

The CH1 signal can not be inverted, there is hence no menu item
in the CH1 menu (CH1 pushbutton

). The TIME/DIV-SCALE-

VAR

knob is disabled.

Please note that the bandwidths and phase differences in XY
analog and DSO modes differ considerably so there may be
changes in the signal display when switching the mode.

32.5.2

DSO mode

The readout will indicate the sampling rate with which the a/d
converters digitise the input signals. The appropriate sampling
rate must be set depending on the signals and can be selected
with the TIME/DIV-SCALE-VAR knob, although the time bases
are disabled. With high sampling rates there may be gaps in
Lissajous representations. With too low sampling rates the
display may not allow any more to determine the frequency
relationship of the signals.
It is recommended to ﬁ rst look at the signals in DUAL mode
and to set the sampling rate such that at least one signal period

VOLTS / DIV

SCALE

VAR

VOLTS / DIV

SCALE

VAR

TIME / DIV

SCALE

VAR

AUTO/

CURSOR

MEASURE