19
HA0114T Rev 10 May 2019
Chapter 3
If
dB
is selected, readings are displayed or returned in decibels. The signal is
first converted to watts according to the calibration factor specified in the A/W
Calibration parameter, and then into dB.
A/W Calibration
- the Amp:Watt calibration factor used when Watts or dBs is
specified in the PIN Units Mode parameter.
BNC Reading Units
Units Mode
-.this parameter specifies the units relating to the input signal
measured by the NanoTrak, and is applicable only if a BNC input source has been
specified.
If
Voltage
is selected, readings are displayed or returned in Volts, i.e. the raw
input signal to the BNC connector.
If
% Full Range
is selected, readings are displayed or returned as a
percentage of full scale input, e.g. a 1V signal into a 2V input range BNC will
display a value of 50%.
If
User Defined
is selected, readings are displayed or returned as a calibrated
value using the Voltage Calibration parameter, e.g. if Voltage Calibration has
been set to '20', a 1V signal into a 2V input range BNC will display a value of
10.
Voltage Calibration
- the calibration factor used when User Defined is selected in
the BNC Units Mode parameter.
This panel is used to modify the autoranging and output characteristics of the
NanoTrak input amplifier circuit (Trans-impedance amplifier (TIA) circuit).
Input Signal Settings
Auto-ranging Mode
- when auto-ranging mode is selected on the GUI panel, range
changes occur whenever the input signal reaches the upper or lower end of the
currently set range.
This parameter specifies how these range changes are implemented by the system.
If
Odd and Even
is selected, the unit visits all ranges when ranging between two
input signal levels.
If
Odd Ranges
(or
Even Ranges
) is selected, only those odd (or even) numbered
ranges between the two input signals levels will be visited. These latter two modes
are useful when large rapid input signal fluctuations are anticipated. This is
because the number of ranges visited is halved to give a more rapid response.
Auto Range Change Limits
- When autoranging, the NanoTrak unit adjusts continually
the TIA range as appropriate for the input signal level. When the relative signal on a
particular range drifts below the limit set in the ‘Lower’ parameter, the NanoTrak unit
decrements the range to the next lower setting. Similarly, when the relative signal