Brandywine FDU-240 User manual

MANUAL P/N 900000035 REV C
User Guide
Frequency Distribution Amplifier
Model FDU-240
P/N 022000001
Revision C
March 2006
Brandywine Communications
1153 Warner Avenue
Tustin, CA 92780
[phone]
[phone]
http://www.brandywinecomm.com/

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Revision History
REVISION DATE COMMENTS
NC 07-14-2004 Original release of FDU-240 user guide.
A 09-08-2004 Revision of entire FDU-240 user guide.
B 02-21-2006 Customer’s comments incorporated into FDU-240 user guide.
C 03-21-2006 Added customer feedback page.

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Safety Warnings
WARNING: This unit contains lethal AC voltages.
Disconnect the unit from the AC supply before removing
the cover.
WARNING:
The lightning flash with an arrowhead inside of an equilateral triangle is
intended to alert the user to the presence of un-insulated “dangerous
voltage” within the product’s enclosure. The “dangerous voltage” may be
of sufficient magnitude to constitute as a risk of electrical shock to people.
CAUTION:
The exclamation point inside of an equilateral triangle is intended to alert
the user to the presence of important operation and maintenance
instructions in the user guide.

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Table of Contents
1Specifications.......................................................................................................................... 5
1.1 Inputs ........................................................................................................................... 5
1.1.1 Reference Frequency Input ................................................................................... 5
1.1.2 Fault Discrete (Optional)........................................................................................ 5
1.1.3 Fault/Status ........................................................................................................... 5
1.2 Outputs.........................................................................................................................6
1.2.1 Reference Frequency Output ................................................................................ 6
1.3 Switches and Indicators ............................................................................................... 7
1.3.1 Status LED Indicators............................................................................................ 7
1.3.2 Environmental........................................................................................................ 7
1.3.3 Power..................................................................................................................... 7
1.3.4 Physical ................................................................................................................. 7
2Option Configuration Sheet..................................................................................................... 8
3Unpacking and Installation......................................................................................................9
3.1 Unpacking .................................................................................................................... 9
3.2 Installation ....................................................................................................................9
3.3 Connections ............................................................................................................... 10
3.3.1 Alarm Input Connection ....................................................................................... 10
4Operation .............................................................................................................................. 11
4.1 Powering the FDU-240 .............................................................................................. 11
4.2 Selecting the Input Reference.................................................................................... 11
4.3 Fault Indicator ............................................................................................................ 11
5Maintenance and Troubleshooting ....................................................................................... 12
6Calibration ............................................................................................................................. 13
7Drawings ............................................................................................................................... 14

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1 Specifications
1.1 Inputs
1.1.1 Reference Frequency Input
•Frequency: 10 MHz ±0.5 ppm
•Amplitude : 0.5 V – 1 Vrms and nominal 1 Vrms factory set
•Input Impedance: 50 ohm
•Number of Inputs: 2 with auto selection and manual override from the
front panel toggle switch
•Connector Type: BNC
1.1.2 Fault Discrete (Optional)
•Number of Inputs: 2
•Level: TTL
•Link selectable for active high or active low
•Forces a changeover when active for online reference
1.1.3 Fault/Status
•Connector Type: DB-9 Female
•Mating Connector: AMP P/N 747904-2

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1.2 Outputs
1.2.1 Reference Frequency Output
•Number of Outputs: 24
•Connector Type: BNC
•Output Protection: short circuit proof
•Frequencies Available (same as input):
o10 MHz
o5 MHz
•Output Level: +13 ±2 dBm standard and specified at time of order
•Stability:
oWith External Reference Only:
+ Same as reference
oWith Free Running Internal Oscillator:
+ Stability vs. Temperature: ±3 x 10
-9
from 0 - 60°C
+ Aging: 5 x 10
-7
per year
•Harmonic Distortion: -45 dBc
•Cross Talk: -80 dBc
•Spurious: -80 dBc
•Phase Noise at 10 MHz:
OFFSET (Hz) SSB PHASE NOISE dBc/Hz
1 -90
10 -110
100 -140
1000 -150
10000 -160

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1.3 Switches and Indicators
1.3.1 Status LED Indicators
•Power (Green)
•Reference Input A Available (Green)
•Reference Input A Online (Green)
•Reference Input B Available (Green)
•Reference Input B Online (Green)
•Automatic Reference Selection Selected (Green)
•Fault (Red)
1.3.2 Environmental
•Temperature:
oOperating: -30 to +60°C
oStorage: -40 to +85°C
•Humidity: 10 - 95% non-condensing
1.3.3 Power
•115/230 VAC 50/60 Hz
•< 25 W
1.3.4 Physical
•1.72” H x 14.5” D x 17.00” W and 1U 19” rack mount
•Weight: 7.5 lbs nominal

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2 Option Configuration Sheet
FDU-240 CONFIGURATION SHEET
PART NUMBER 022000001
CONNECTOR FUNCTION LEVEL INSTALLED
J1 ALARM INPUT
PIN 1 STATUS A
PIN 2 STATUS B
PIN 3 NO CONN
PIN 4 NO CONN
PIN 5 NO CONN
PIN 6 GROUND
PIN 7 GROUND
PIN 8 GROUND
PIN 9 NO CONN
ACTIVE H__L b
ACTIVE H__L
b
b
REFERENCE A INPUT 1.0 V rms
b
J3
FREQUENCY 10 MHz
REFERENCE
A
SOURCE
EXTERNAL
_____b_____
FREE RUNNING
OCXO
____________
OCXO PHASE
LOCKED TO
REFERENCE
__________
REFERENCE B INPUT 1.0 V rms
b
J2
FREQUENCY 10 MHz
REFERENCE
B
SOURCE
EXTERNAL
____b______
FREE RUNNING
OCXO
____________
OCXO PHASE
LOCKED TO
REFERENCE
__________
FREQUENCY OUTPUT 1.0 V rms
b
J4 - J27
LEVEL 10 ±1 dBm
AC POWER 115 VAC
b

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3 Unpacking and Installation
3.1 Unpacking
Carefully remove the FDU-240 from its shipping carton. The following items
should be included in the shipment:
•1 FDU-240
•1 power cord
•1 user guide
Note the power entry module on the rear of the FDU-240 chassis. Please take
note of the voltage displayed on the rear of the power entry module and verify
that the voltage matches the local line’s voltage.
CAUTION:
THE FDU-240 WILL BE DAMAGED IF THE INCORRECT AC
LINE SETTING IS USED.
WARNING:
REMOVE THE POWER CORD FROM THE FDU-240 BEFORE
ADJUSTING THE LINE VOLTAGE.
If the AC line setting is incorrect, detach the power cord from the power entry
module. Use a small screwdriver to lift up the fuse cover on the power entry
module to remove the fuse holder. Reverse the fuse holder and re-insert the
fuse holder, making sure that the correct AC line voltage is now displayed on the
rear panel.
3.2 Installation
The FDU-240 should be bolted directly into a 19” rack mount enclosure or
mounted on a shelf. The FDU-240 when fully populated has up to 27 cables
attached to the rear panel, therefore it is recommended that some appropriate
cable strain-relief system be used to support these cables, particularly when the
unit is not supported by a shelf.

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3.3 Connections
Insert the power cord provided in the shipment into the rear power entry module.
Connect the input reference signals to the appropriate connectors on the rear
panel.
CAUTION:
FOR CORRECT OPERATION, REFERENCE FREQUENCY A
AND REFERENCE FREQUENCY B MUST BE THE SAME
FREQUENCY, WHICH IS TYPICALLY 10 MHz.
Connect the output cables to the desired output connectors. Any unused
connectors may be left un-terminated.
3.3.1 Alarm Input Connection
The FDU-240 may be used with an external reference such as the Brandywine
Communications GPS8 or PTS system that incorporates a discrete alarm signal.
This alarm signal is used to indicate a fault (e.g. rubidium out of lock) on the
reference signal, although the 10 MHz input signals may be present.
The factory standard FDU-240 configuration is a logic HI signal on the ALARM IN
pin indicating that the input is GOOD. A built in pull-up resistor ensures that if no
ALARM IN connection is made the reference is considered good. To change the
polarity of the ALARM IN, remove the top cover of the FDU-240 and set the links
to the link settings seen in the table below.
LINK SETTING REFERENCE A STATUS
LK1 2-3 HI – reference A is GOOD
LK1 1-2 LO – reference A is GOOD
LINK SETTING REFERENCE B STATUS
LK2 2-3 HI – reference B is GOOD
LK2 1-2 LO – reference B is GOOD

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4 Operation
Refer to Figure 1 for a guide of the front panel controls and indicators.
4.1 Powering the FDU-240
Once all connections to the FDU-240 have been made, apply power to the unit
by placing the on/off switch to the on position. The on/off switch is located on the
rear panel power entry module.
If an external reference is fitted, verify that the two green LEDs Reference A
Available (1) and Reference B Available (2) are illuminated. This indicates that
the FDU-240 has detected the presence of the external references.
Place the Reference Select Switch (3) in the center (AUTO) position. The green
Reference A Online LED (4) and the AUTO LED (6) should illuminate. This
indicates that the FDU-240 outputs will be driven from Reference A and if
Reference A fails, it will automatically switch to Reference B.
If an internal oscillator is installed, allow 5 - 10 minutes for the initial warm up of
the frequency reference. The FDU-240 is now ready for operation.
4.2 Selecting the Input Reference
The external reference frequency used is selected by the Reference Select
Switch (3). Moving the switch to the left position will select input A as the
reference. Moving the switch to the right position will select input B as the
reference. The center (AUTO) position will use Reference A as the input if it is
present and the status indicator indicates that it is good.
Either one or two internal oscillators may be installed. If one is installed, it is
always installed as Reference A. To operate as a free running standard, leave
the reference select switch in the left position.
4.3 Fault Indicator
The red LED on the front panel indicates that one or more of the outputs has a
low signal. There are four potential causes for this as listed below:
1. There is no input signal or the internal OCXO (if fitted) has failed.
2. Input B has been manually selected and there is no input signal
connected to reference Input B.
3. One or more output buffers have failed.
4. There is a short on an output cable.

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5 Maintenance and Troubleshooting
There is no preventive maintenance required for the FDU-240.
SYMPTOM POTENTIAL CAUSE CORRECTIVE ACTION
No signal
outputs
1. There is no input
reference.
2. The Reference Select
switch is selecting
Reference B when an
internal OCXO is used.
3. There is a failed internal
source.
1. Connect the reference
input.
2. Select an internal source.
3. Return to factory for repair.
Fault light
illuminated
1. There is an internal
OCXO failure.
2. There is a failed output
driver.
3. There is an excessive
load on one or more
outputs.
4. The output level is
adjusted too low.
1. Return to factory for repair.
2. Return to factory for repair.
3. Disconnect the output
loads one by one until the
overloaded output is
isolated. Outputs should
not have a load < 50 ohm.
4. Isolate the low output level
and adjust for a level that
is > 10 dBm.

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6 Calibration
Calibration is only applicable to units fitted with a free running internal OCXO.
The center frequency of the OCXO may be periodically adjusted to compensate
for aging.
1. Remove the top cover of the FDU-240 and put it aside.
2. Identify the internal OCXO and remove the 4 - 40 screw that covers the
calibration access hole.
3. Allow the unit to operate for 24 hours to allow the OCXO to fully stabilize.
4. Connect one of the 10 MHz reference outputs to a frequency counter with
at least an 11 digit resolution.
CAUTION:
The frequency counter MUST be configured to use an external reference
such as a Cesium, Rubidium, or GPS disciplined OCXO as its time-base.
The calibration accuracy of the FDU-240 can only be as accurate as the
reference against which it is calibrated. It should be better than 1x10
-10
5. Using a very small screwdriver, insert it carefully into the OCXO
adjustment access hole until it engages with the slot in the adjustment
potentiometer. Slowly adjust the potentiometer until the frequency counter
reads 10.000000000 ±5 MHz.

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7 Drawings
FIGURE DESCRIPTION
1 FDU-240 Front Panel
2 FDU-240 Rear Panel
3 FDU-240 Mechanical Outline
4 FDU-240 Link Location

1153 Warner Avenue
Tustin, CA 92780
714 755 1050 Tel
714 755 0175 Fax
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