Basic Functions; Main Generator Operation - Metrix GX1010 Notice De Fonctionnement

4.2.

Basic functions

4.2.1. Main Generator Operation

When first switched on, and at all subsequent power-ups unless specified otherwise on the
SYStem menu, the generator will be set to the factory defaults, with the output off. The
basic parameters can be set from the Main menu as described below.
4.2.1.1. Frequency
With the flashing edit cursor anywhere on the first line of the Main menu the frequency can
be changed directly from the keyboard by entering the number and appropriate units only,
e.g. 1kHz can be set by entering 1,kHz or ·, 0, 0, 1, MHz or 1, 0, 0, 0, Hz, etc. However, the
display will always show the entry in the most appropriate engineering units, in this case
1.000000 kHz. If this cursor is not already in a top line field it is first necessary to press the
FREQ/PER key before making the number and unit entry. Note that this always returns the
cursor to the parameter name field which can then be alternated between FREQ and
PERiod with successive presses of either DIGIT key, or by turning the rotary control.
When PER= shows in the display instead of FREQ=, the frequency can be set in terms of a
period; enter the number and units (ns, µs, ms or s) in the same way as for frequency.
Note that the precision of a period entry is restricted to 6 digits; 7 digits are displayed but
the last significant one is always zero. The hardware is always programmed in terms of
frequency; when a period entry is made the synthesised frequency is the nearest
equivalent value that the frequency resolution and a 6-digit conversion calculation gives. If
the frequency is displayed after a period entry the value may differ by a digit from the
expected value because of these considerations. Further, once the setting has been
displayed as a frequency, converting back again to display period will give an exact 6-digit
equivalent of the 7-digit frequency, but this may differ, by a digit, from the period value
originally entered. If the edit cursor is moved to the numeric field, turning the rotary control
will increment or decrement the numeric value in steps determined by the edit position
within the field. The FIELD keys move the cursor to the field and the DIGIT keys move it
within the field; this is more fully explained in the Principles of Editing section. Lastly, with
the edit cursor in the units field, pressing the DIGIT keys or turning the rotary control will
change the value in decade increments; the decimal point will move and/or the units will
change as appropriate. Full 7-digit precision is maintained as the value is decremented
until the 0·1mHz resolution limit of the instrument is reached; values which would have had
least significant bits <0·1mHz are truncated with further decrements and the precision is
consequently lost when the number is incremented again.
4.2.1.2. Output Level
The second line of the Main menu permits the output level to be set in terms of EMF (open
circuit voltage) or PD (potential difference into a matched load) or dBm (referenced to the
specified source impedance). Both EMF and PD can be set in terms of peak-peak volts
(Vpp) or r.m.s. volts (Vrms). Note that in both cases the true peak-peak or r.m.s. values are
shown for the selected waveform, even an arbitrary waveform. However, in the case of
14 - II
FREQ=10.00000kHz
EMF =+20.0 Vpp
DC=+0.00mV (+0.00mV)
SYM=50.0% (50.0%)
PER =100.0000us
EMF =+20.0 Vpp
DC=+0.00mV (+0.00mV)
SYM=50.0% (50.0%)
50Ω Ω Ω Ω
50Ω Ω Ω Ω
GX1010