Doh!!! I can´t beleive i made this question without read the manual of my DSO oscilloscope (TEK TBS 1072B-EDU) that shows the trigger can be sourced by CH1,CH2, EXT, EXT/5 AC LINE.
Now i remebering about this from oscilloscopes classes at engeneering school. (19yr´sa ago).
Same thing with the
RiGOL DS1054Z manual on section
5-2:pag 76Trigger SourcePress MENU Source in the trigger control area (TRIGGER) at the front panel to
select the desired trigger source. Analog channels CH1-CH4, digital channels D0-D15
or the AC Line can all be used as trigger source.
Analog channel input:Signals input from analog channels CH1-CH4 can all be used as trigger source. No
matter whether the channel selected is enabled, the channel can work normally.
Note: When any channel among D7-D0 is enabled, CH4 cannot be used as trigger
source; when any channel among D15-D8 is enabled, CH3 cannot be used as trigger
source.
Digital channel input:Only the digital channels turned on can be used as trigger source. Please refer to the
introduction of "To Turn on/off the Digital Channel" to turn on the desired
digital channel.
AC line:The trigger signal is obtained from the AC power input of the oscilloscope. AC trigger
is usually used to measure signals relevant to the AC power frequency. For example,
stably trigger the waveform output from the transformer of a transformer substation;
it is mainly used in related measurements of the power industry
Just to make shure if i understood this..., if i just need from channel 1-3 to show signal, i still have the channel 4 as a tigger source (in this case, turned into a external trigger)?
As i´m returning to electronics world, planning to buy a RIGOL, need study more, instead of make silly questions again.
Anyway, Thanks for the answers and for your time...
Att