SRS Labs SR850 - Manual (Page 28)

2-16
Press <Source>
Use the knob to select Trace1.
8. Press [TRACE/SCAN]
Press the second softkey, next to the trace
definition, to highlight the X.
Use the knob to change the numerator from X
to 1.
Press the second softkey twice to highlight the
denominator (C) of the trace definition.
Use the knob to change the denominator from
1 to X.
should be 5.0 V.
Highlight the CH1 source. The CH1 output is pro-
portional to this source.
CH1 can be proportional to X, R,
θ
, or Trace 1-4.
Choose Trace 1. Trace 1 has a default definition of
X so the CH1 output should remain 5.0 V (but its
bandwidth is only 200 Hz instead of 100 kHz).
Display the Trace and Scan menu.
Traces are defined as A•B/C. The quantities A, B,
and C are selected from the various quantities
measured by the lock-in.
Trace 1 is defined as X by default. Let's change it
to 1/X.
Trace 1 is now 1•1/1 and the top display shows
1.000
Change the denominator.
Trace 1 is now defined as 1/X. The top display
shows Trace 1. The trace definition is shown at
the upper left of the top display. The trace units
are shown at the bottom center of the top display
(1/V).
Remember, X was 0.5V. Thus, 1/X is 1/0.5 = 2.0
(1/V). The display should show 2.0 (or very close).
Displays use the actual measured quantities to
calculate the value of a trace. If X was 5 mV, the
value of Trace 1 would be 1/5 mV or 200 (1/V).
Traces are calculated using Volts, degrees, and
Hz for the units of A, B and C.
The CH1 output voltage is 0.2V. This is because
trace output voltages are calculated using the
output voltages of the A, B and C quantities rather
than their displayed values. In this case, X=0.5V.
As an analog output voltage, this would be 5.0 V
(1/2 scale of 1V full scale sensitivity). The 1/X
output voltage is 1/5.0V or 0.2 V.
See the DC Outputs and Scaling discussion in the
Lock-In Basics section for more detailed
information.
Outputs, Offsets and Expands