MOGlabs DLC202, Руководство пользователя, Страница: 51 / 82

A.1
RF
response 41
A.1
RF
response
*
*
RBW 30 kHz
VBW 10 MHz
SWT 17 s Att 50 dB
*
TG -30 dBm
Ref -20 dBm
Center 1.5 GHz Span 3 GHz 300 MHz/
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
Figure A.1:
RF
response,
SMA
input on laser headboard to diode SMA
output.
A.2 Sweep saturation and trigger
In normal scanning mode, a sawtooth is supplied to the stack piezo
(or other laser frequency actuator), at a frequency of 1 to 70 Hz; see
fig. A.2. At the nominal midpoint of the sweep, a trigger (low to high)
signal is output via the rear panel
TRIG
connection, for synchronising
to an oscilloscope or external experiment.
The span may be limited by the minimum and maximum voltage that
can be applied to the actuator, 0 and 120 V [150 V optional]. That is,
the ramp may “saturate”, as shown in fig. A.2. The period remains
fixed, and the trigger remains at the centre of the period, but the
laser frequency will not scan for the entire period. Thus the spectrum
will appear to shift to the left or right of centre and will be “flat” for
part of the span. For situations where complete linear spectra are
needed, the actual ramp output should be monitored using the
Freq
selection of the
CHAN A
output.