Lok-to-Clock Electronics
8-7
REF IN connector—provides connection for either a user-defined external
reference signal (defined at time of purchase) or the 80 MHz internal refer-
ence signal. When the internal reference is used, a BNC cable connects
from the 80 MHz OUT connector to this connector (Figure 8-5). An input rf
signal of between 76 and 83 MHz can be accepted provided the laser cavity
length has been factory preset. Input impedance is 50 Ω at 0 dBm for a sine
wave.
REF OUT connector—provides a buffered signal from the selected refer-
ence input signal for use with an external frequency counter or other user
equipment. Output impedance is 50 Ω at 0 dBm for a sine wave.
REF ÷ 8 connector—provides a buffered 8:1 frequency-divided signal
from the selected reference input signal for use with an external frequency
counter or other user equipment. When the internal reference is used, out-
put is 10 MHz. Output impedance is 50 Ω at 0 dBm for a sine wave.
80 MHz OUT connector—provides a buffered 80 MHz sine wave signal
from the internal reference source. It can be used for the REF IN reference
input signal in lieu of an external, user-supplied signal. Output impedance
is 50 Ω at 0 dBm for a sine wave.
Installing the Model 3930
Note: you must have a Model 3960C, 3950C, or 3941C version Tsunami
laser head to use this system.
The Model 3930 is easy to install. Merely install the PZT-controlled M
4
mir-
ror in the Tsunami laser head and connect the
BNC and ribbon cables
between the Model 3930 and the laser head. There may be other connec-
tions depending on the requirements of the experiment or lab setup (for
oscilloscope, external photodiode, etc.). The following procedure covers
most standard installations and assumes the Tsunami laser is properly
aligned according to Chapter 6, “Alignment,” and is running according to
Chapter 7, “Operation.”
1. Place the Tsunami Model 3955 electronics module on top of the Model
3930. Both modules should be within 1 m of the Tsunami laser head.
2. Attach the 25-pin ribbon connector (from the accessory kit) between
the TO HEAD connector on the rear panel of the Model 3930 and the
TO 3930 female connector on the input bezel of the Tsunami laser
head.
3. Disconnect the 50 Ω terminator on the
LTC PD connector and place it in
the tool kit.
4. Attach a BNC cable between the PHOTODIODE IN connector on the
Model 3930 and the LTC P D connector on the Tsunami laser head.
Do not connect the BNC cable from the PHOTODIODE IN connector to
the ML PD connector on the laser head. The photodiode signals from ML
PD
and LTC PD are calibrated differently and ML PD will over-drive the
PHOTODIODE IN connector if swapped.
Caution!
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