OPTO-ELECTRONIC DRFA Series User manual

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
Variable Frequency Drivers
OEM and Laboratory versions
DRFAxx
_____________________________________________
CONTENTS
INTRODUCTION ...............................................................................................................2
PRECAUTIONS.................................................................................................................3
MECHANICAL ...................................................................................................................3
ELECTRICAL CONNECTIONS .........................................................................................4
INSTALLATION .................................................................................................................4
QUICK START AND OPERATION....................................................................................5
GLOSSARY.......................................................................................................................9

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
WARRANTY
AA OPTO-ELECTRONIC guarantees its products to be free of defects for one year from
the date of shipment. This is in lieu of all other guarantees, expressed or implied, and does
not cover incidental or consequential loss.
Information in this document is subject to change without notice.
Document Number DRFA ed 20018-1.
INTRODUCTION
The AA Opto-Electronic DRFA drivers are variable frequency drivers based on VCOs,
Voltage Controlled Oscillators.
They produce an RF signal which frequency is controlled thanks to an analog voltage
between 0 and 10 volts. They are suitable for easy set up and raster scan applications.
They frequency range is generally set at factory to match the acousto-optic frequency
range.
The amplitude can be varied thanks to an analog signal between 0 and 5 volts.
An external power amplifier must be added in order to reach the necessary RF power to
operate the acousto-optic device.
The Laboratory versions are desktops supplied with 110-230VAC (wall plug). Cooling and
DC supplies are built in the box. External power amplifiers are also built in the box.
AA offers one output versions and 2 outputs versions. The 2 outputs versions are generally
used for 2-axis deflectors.
For these laboratory versions, a front panel knob and switch are associated to the external
AM control in order to allow user to control power manually.
A front panel knob and switch are associated to the external FM control in order to allow
user to control frequency manually from minimum to maximum of the range.
To have the exact specifications of your driver, please refer to the test sheet provided with
each unit.

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
PRECAUTIONS
Never operate the output of your DRFAxx in open circuit or short circuit, or irreversible
damages could result. The output must always be connected to a 50Ohms load or an
AO device.
Be careful to never exceed the maximum recommended voltages, especially for DC
power supply, AM and FM controls, or irreversible damages may happen.
The OEM version of the DRFAxx must always be installed on a metal plate or heatsink
in order to evacuate heat through the baseplate. Case temperature must not exceed
50°C or life time of the DRFAxx can be reduced.
MECHANICAL DRAWING (OEM, mm)

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
ELECTRICAL CONNECTIONS
Screw potentiometer
Max RF power adjust
RF Output
To be connected to
Power amplifier,
AO device
or 50 ohms load
External Modulation
input (AM)
Power Supply
External Frequency
Control (FM)
0dBm output (option)
For frequency monitoring
External Modulation
input (AM)
External Frequency
Control (FM)
RF Output
To be connected to
Power amplifier,
AO device
or 50 ohms load
0dBm output (option)
For frequency monitoring

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
INSTALLATION
Install your OEM driver on a heatsink or metallic plate. Screw it firmly by using the 2 or 4
fixation holes. Use conducting thermal grease if necessary in order to allow an efficient
thermal conduction.
All OEM drivers have heat exchange through based plate and must be correctly cooled in
order to maximize life time. Cooling is optimum when Case temperature does not exceed
50°C.
The laboratory versions are power supplied with 110-230VAC. They are designed to
operate as table top drivers, with built-in DC power supply and necessary cooling elements.
The RF output of your driver must always be connected to a power amplifier, an AOM or a
50 ohms load to avoid irreversible damages.
QUICK START AND OPERATION
This section presents a brief introduction to using your DRFAxx driver in association with
an acousto-optic device.
OEM versions
Connect Power supply. Standard models are 24VDC. Please refer to your test sheet for
exact voltage and necessary current. Use the male connector provided by AA (PHOENIX
CONTACT MSTB 2.5/2-ST-5.08).
Connect the RF Output « RF OUT » to the Power amplifier or AO device (or 50 Ωpower
termination). Use a convient 50 ohms RF cable.

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
Connect the external modulation input « MOD IN » for AM control. Please refer to your test
sheet for exact signal amplitude and impedance.
Connect the external Frequency input « FREQ IN » for FM control. Please refer to your
test sheet for exact signal amplitude and impedance.
If the option is available, connect the external 0dBm output to an oscilloscope or frequency
meter. The level of this output will be constant (0dBm) and frequency will be simaly to the
RF output. It is used for frequency monitoring.
At this step we recommend to not touch the Gain and offset potentiometers.
Your driver is ready to operate. Switch ON power supply. Switch ON the AM and FM control
signals. We advise 15 minutes warm up to reach the best stability.
Maximum RF power level adjustment:
A screw potentiometer ("Power Adj.") is available to fully adjust the
maximum RF power level from 0 to a maximum value (see test sheet).
To adjust the maximum RF power level, your modulation input must be
active, with the maximum level (+5VDC for instance). At the contrary,
the output RF power of your driver will be only a fraction of the maximum
signal. For more information, refer to "Amplitude modulation" part.
With a screwdriver (2,2 mm large) :
- rotate the multi-turn potentiometer to clockwise to decrease RF power.
- rotate reverse side to increase RF power.
When monitoring the output signal from your driver, you will observe a sine wave, which
frequency is equal to the carrier frequency of your driver, and which amplitude is set via
the POWER ADJ.
Frequency range adjustments: GAIN and OFFSET potentiometers
OEM drivers only:
The minimum and maximum frequencies are set at factory, and can
be slightly adjusted with potentiometers "OFFSET" and "GAIN".
With a screwdriver (2.2 mm large) :
- rotate the potentiometer "OFFSET" to adjust centre frequency Fc.
- rotate the potentiometer "GAIN" to adjust frequency range (Fmin-
Fmax) without modifying centre frequency.

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
V
pp
Frequency
V
pp
Frequency
V
pp
Vpp
0
Fmin Fc Fmax
GAIN ADJUST
Fmin1 Fc
Fmax1
Frequency
Fmin Fc1
Fmax
OFFSET ADJUST
Laboratory versions
Connect the rear pannel plug of the Laboratory driver to 110-230VAC supply.
Do not connect any other power supply than 110-230VAC.
Connect the SMA RF Output « RF OUT » to the AO device (or 50 Ωpower termination).
Use a convient 50 ohms RF cable. For a double outputs driver, both outputs must be
connected.
Connect the external modulation input « MOD IN » for AM control. Please refer to your test
sheet for exact signal amplitude and impedance. Use BNC front pannel connector « MOD
IN ».
Connect the external Frequency input control « FREQ IN » for FM control. Please refer to
your test sheet for exact signal amplitude and impedance. Use BNC front pannel connector
« FREQ IN ».

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
Front panel switch EXT/CW:
When set in CW mode, the user’s external signal is disabled; driver provides internally the
necessary signal to operate the driver (stand alone mode). For Analog control, the front
panel knob allows to vary the output power or Frequency from minimum to maximum.
Attention, for amplitude control, the position of the knob also adjusts the maximum power
level in EXTernal operation.
When set in EXT mode (External), then the user’s external signals are used to operate the
driver. Attention for Amplitude control with analog signals, the knob position adjusts the
maximum RF power level.
Your driver is ready to operate. Switch ON power supply. Switch ON the AM control
signal(s). We advise 15 minutes warm up to reach the best stability.
Maximum RF power level adjustment/Frequency adjustment
Laboratory Driver:
A screw potentiometer ("0…Pmax.") is available from front panel to fully
adjust the maximum RF power level from 0 to a maximum value (see
test sheet). Please note that this is the same adjustment for Internal and
External Modulation control.
To adjust the maximum RF power level, your modulation input must be
active, with the maximum level. At the contrary, the output RF power of
your driver will be only a fraction of the maximum signal. For more
information, refer to "Amplitude modulation" part.
(CW mode) A screw potentiometer ("Fmin…Fmax.") is available from
front panel to fully adjust the frequency level from Fmin to Fmax value
(see test sheet).
When monitoring the output signal from your driver, you will observe a sine wave, which
frequency is equal to the carrier frequency of your driver, and which amplitude is set via
the POWER ADJ.
Fmin Fmax
0
Pmax

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
GLOSSARY
•Output RF power (P
RF
)
The output RF power P
RF
through a 50 Ωload (R) is related to the peak to peak signal
amplitude Vpp by the relation:





8 


400
•VSWR (Voltage Stationary Wave Ratio)
This parameter gives an information on the reflected and transmitted RF power to a
system.
In order to have the best matching between an acousto-optic device and a radio frequency
source/amplifier, one will have to optimize both impedance matching on the source and
the driver. Generally, input impedance of an acousto-optic device is fixed to 50 Ohms as
well as the output impedance of the driver/amplifier.
VSWR Reflected POWER
1.002 / 1 0.0001 %
1.068 / 1 0.1 %
1.15 / 1 0.5 %
1.22 / 1 1 %

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
1.5 / 1 4 %
2 / 1 11 %
2.5 / 1 18 %
3 / 1 25 %
•Amplitude Modulation (AM Control)
ANALOG MODULATION (0-Vmax)
The analog modulation input of your driver controls linearly and continuously the output RF
amplitude of the signal from 0 to maximum level.
When applying 0 V on “MOD IN”, no output signal
When applying Vmax on “MOD IN”, maximum output signal level
The output RF waveform is a double-sideband amplitude modulation carrier.
Vmax can be adjusted at factory from 1 V to 10 V.

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
TTL MODULATION (ON/OFF)
The TTL modulation input of your driver is compatible with standard TTL signals. It allows
the driver to be driven ON and OFF.
- When applying a “0” level (< 0.8 V) on “MOD IN”, no output signal.
- When applying “1” level (> 2.4 V) on “MOD IN”, maximum output signal level.
It will be noted that a TTL modulation input can be piloted with an analog input signal.
Digital 8 bit AMPLITUDE MODULATION
A byte (8 bit //) controls the amplitude of the output RF signal. A D/A converter converts
the 8 bits command (N) on an analog signal which controls linearly the output amplitude.
256 levels are available
- When N=00000000, no output RF signal
- When N=11111111, maximum output level
Binary code
00000000 01000000 11111111

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
•Rise and Fall Time (T
r
/T
f
)
The rise time T
r
and fall time T
f
of your driver specified in your test sheet corresponds to
the necessary time for the output RF signal to rise from 10 % to 90 % of the maximum
amplitude value, after a leading edge front. This time is linked to carrier frequency and RF
technology. The class A drivers from AA, offer the best rise/fall time performances.
•Extinction Ratio (ER)
The extinction ratio of your driver specified in the test sheet is the ratio between the
maximum output RF power level Pmax (MOD IN = max value) with the minimum output
level Pmin (MOD IN = 0).
A bad modulation input signal can be responsible for the extinction ratio deterioration.
ER  10 log 



  20  
 

 


User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
Analog Frequency Control (VCO)
Laboratory driver versions: Selector must be set on EXT position.
FREQ IN: the frequency control input of your driver controls linearly and continuously the
output RF frequency of the signal from Fmin (minimum frequency) to Fmax (maximum
frequency) thanks to a voltage between 0 and 10 Volts (1 kohms).
The typical linearity of the frequency versus input command is +/- 5% (less on option).
Frequency Sweeping time (VCO)
This is the minimum necessary time to sweep frequency from minimum to maximum, or
maximum to minimum.
This value will be taken as the maximum random access time, though it depends on the
frequency step.
When applying 0 V on "FREQ IN", Frequency = Fmin
When applying V
max
on "FREQ IN", Frequency = Fmax
(Standard frequency control input : 0-10 V / 1 kΩ).

User’s Guide
DRFA Ed 2018-1
AA OPTO-ELECTRONIC Tel: [phone]
18, rue Nicolas Appert Fax: [phone]
91898 ORSAY FRANCE www.aaoptoelectronic.com
AA Sa reserves the right to make changes to the products or information herein
without notice. No liability is assumed as a result of their use or application.
0 dBm Output (Option)
This output delivers a portion of the output RF signal, at constant amplitude level (0 dBm).
It can be directly linked to an oscilloscope or a frequency meter in order to monitor the
frequency of your driver, as well as the frequency drift versus temperature.