User Manual

AC
Set A Input to AC coupling.
DC
Set A Input to DC coupling.
Z1
Set A Input to 1MΩ input impedance.
Z5
Set A Input to 50Ω input impedance.
A1
Set A Input to 1:1 attenuation.
A5
Set A Input to 5:1 attenuation.
ER
Set rising edge of waveform as start of measurement.
EF
Set falling edge of waveform as start of measurement.
FI
Low Pass Filter In (on).
FO
Low Pass Filter Out (off).
When remote state is first entered the filter stays set as it was in the local state. When
remote state is cleared the filter setting remains as it was in the remote state.
L
Low frequency mode. Applicable to TF830 only. Command accepted but ignored by TF930,
which is automatically in low frequency mode while DC coupling is selected.
Threshold Commands
TO <nr1>
Use with AC coupling. Threshold automatically adjusts to the average level of the waveform
being measured, offset by <nr1> mV, where <nr1> is a number in the range -60 to +60; if
no sign is present, <nr1> is assumed to be positive.
TO? Returns the current TO Threshold value in the form SnnnnmV<rmt>, where S is the sign,
nnnn is the Threshold voltage in mV and mV is the units specifier. S is only present if the
sign is negative.
TT <nr1>
Use with DC coupling. Threshold set to a level of <nr1> mV, where <nr1> is a number in
the range -300 to +2100; if no sign is present, <nr1> is assumed to be positive.
TT? Returns the current TT Threshold value in the form SnnnnmV<rmt>, where S is the sign,
nnnn is the Threshold voltage in mV and mV is the units specifier. S is only present if the
sign is negative.
Values for TT and TO assume an input attenuation setting of 1:1; for 5:1 attenuation the effective levels
will be the set value x 5.
TA
Use with DC coupling. Threshold Level set to achieve auto triggering; the threshold
automatically adjusts to the average level of the waveform being measured (no offset).
In all cases the threshold level is set irrespective of the position of the front panel control. When remote
state is first entered the trigger level is exactly as it had been set from the front panel (the TO? or TT?
command can be used to read this value, corresponding to whether AC or DC coupling is currently set).
When the remote state is cleared the trigger level reverts to the setting determined by the current front
panel control position. Note that although mV resolution is provided, offsets within the instrument result in
the actual value being only approximately correct. It is accurate enough to allow the setting of standard
logic thresholds, but if maximum sensitivity to small signals is required when DC coupled then some
experiment may be required.
Using TO <nr1> with DC coupling or TT <nr1> with AC coupling may give unpredictable results; it is up
to the user to use settings consistent with each other and with the measurement application.
TA requires the user to first set DC coupling; TA can be useful for automatically finding a useable
measurement threshold for low frequency waveforms that require DC coupling, or for higher frequency
waveforms with very small duty cycles. There is no equivalent front panel setting.
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