SDI LNFR-100E User manual

SPECTRADYNAMICS, INC.
LOW NOISE FREQUENCY REFERENCE
LNFR-100E
OPERATING MANUAL
SPECTRADYNAMICS, INC •1849 Cherry St. Unit 2. •Louisville, CO 80027
Phone: [phone] •Fax: [phone]
www.spectradynamics.com
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The LNFR-100E is a high performance 10 MHz distributed frequency reference.
It contains a 5 MHz SC-cut ovenized oscillator, a low noise frequency doubler and a
distribution amplifier module. The 10 MHz signal is distributed by the distribution
amplifier to provide four 10 MHz outputs. Typical cross-channel isolation is 70 dB and
reverse isolation is typically greater than 75 dB. The distribution module does not
degrade the phase noise performance of the oscillator that is typically –142 dBc/Hz @
Fourier frequency of 10 Hz and –168 dBc/Hz @ Fourier frequency greater than 10 kHz.
The LNFR-100E outputs are matched to 50 ohms to obtain better than 25 dB return
loss. The LNFR-100E can be phase locked via an electrical tuning port or by providing
an external 10 MHz reference.
Theory of operation
The LNFR-100E contains a 5 MHz SC cut, ovenized oscillator. The output of the
oscillator is doubled in frequency and distributed with a high performance distribution
amplifier. Four 10 MHz outputs are provided on the back panel. A buffered 10 MHz
signal is used internally to phase lock the oscillator to an external 10 MHz input.
LNFR-100E Description
SDI
SPECTRADYNAMICS,INC •1849 Cherry St Unit 2. •Louisville, CO 80027 •Phone: [phone] •Fax: [phone]
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CAUTION!
Voltages capable of causing injury or death are present in this instrument. Use extreme
caution whenever the instrument cover is removed.
Line Voltage
This instrument can be setup to operate on 110-120 or 220-240 VAC and a line
frequency of 50 to 60 Hz. For conversion to a different line voltage please contact SDI.
Fuse
A 1.0-Ampere 250V slow blow fuse is used in this instrument for 110-120 VAC line
voltage. A 0.5-Ampere 250V slow blow fuse is used for 220-240 VAC line voltage. Do
not replace with a larger fuse.
Line Cord
The LNFR-100E has a detachable three-wire power cord for connection to a grounded
power source. The enclosure of the unit is directly connected to the outlet ground to
protect against electrical shock. Always use an outlet with a protective ground and do
not disable this safety mechanism.
Service
Do not attempt to service or adjust the instrument unless another person, capable of
providing first aid or resuscitation, is present.
Operation
To operate the unit, locate the AC power entry connector on the rear panel and connect
the power cable. When power is applied to the unit, a red led located on the front panel
labeled “on”, should light up.
Safety and Preparation for Use
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Power
The LED is on when power is applied to unit and the unit is operating properly.
External Reference
Signal The LED is on when a 10 MHz reference is applied to the tuning
port and the reference select switch is in the 10 MHz position.
DC/10 MHz Tuning mode select switch used to change from DC tuning mode to
10 MHz external PLL mode.
10 MHz Status
Signal The LED is on when the internal oscillator is operating properly.
Locked The LED is on when the internal 10 MHz oscillator is phase-locked
to the external 10 MHz reference. This LED is always off when the
instrument is operating in DC tuning mode.
The Front Panel
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External Reference
Tuning Type N input connector used to supply a 10 MHz reference to the
instrument or a +/- 5VDC tuning voltage.
10 MHz Outputs
J1 – J4 Type N output connector providing the 10 MHz output signals.
AC Power Entry Module
The LNFR-100E is factory configured to operate on 110 to 120 VAC.
The Back Panel
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To operate the unit, locate the power entry module on the rear of the enclosure
and connect the power cord. Plug the unit into an appropriate power outlet and turn the
unit on. A red LED on the front panel labeled “Power” will turn on.
The 10 MHz source requires a one-hour warm up period for the output frequency
to stabilize. The frequency of the 10 MHz source can be adjusted through the tuning
port on the back panel. The tuning port has two modes of operation, DC tuning and
automatic frequency locking. The mode of operation is selected with the tuning select
switch. In the DC position a +/- 5VDC signal can be used to adjust the frequency of the
LNFR-100E. The tuning port sensitivity is 0.5 Hz/Volt and the frequency modulation
bandwidth is approximately 300 Hz. In the 10 MHz position the LNFR-100E will phase-
lock to a 10 MHz signal provided at the tuning port. The external reference signal level
must be between +7 dBm and +15 dBm for proper operation. The PLL bandwidth has
been set to 2 Hz at the factory. For different PLL bandwidth requirements please
contact SDI.
Operation
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Mechanical frequency tuning is available to adjust the frequency of the
oscillators. Only fully qualified service personnel should perform this procedure.
Frequency adjustments should be made with the unit having been powered on for at
least 1 hour. Caution must be used to avoid shorting or accidentally touching a
line voltage point.
Before you begin the mechanical tuning adjustment disconnect any signal going
to the back panel tuning port. Connect one of the outputs to a frequency counter and
make sure that the counter has an accurate frequency reference. The top cover of the
LNFR-100E must be removed to perform the mechanical tuning. Locate the 5 MHz
oscillator. On the right side panel there is an access hole so that a small flat blade
screwdriver can be inserted. Guide the screwdriver from the top and remove the
hermetic cover screw to gain access to the tuning screw. Using a tuning tool or small
screwdriver adjust the frequency of the 5 MHz oscillator to the desired frequency with
the tuning select switch set to the DC position and not having any DC or AC signals on
the tuning port. Replace all hermetic covers when done adjusting the frequency of the
oscillators. Replace the top cover of the LNFR-100E.
Note: The LNFR-100E should be turned on for 1 hour prior to any mechanical
frequency adjustment.
Mechanical Tuning
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LNFR-100E Specifications
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Level 50 ohm load +11 +14 +15 dBm
Output Impedance Return Loss @ 10
MHz
-25 dB
Harmonic Distortion 50 ohm load -40 -38 dBc
Isolation output to output 60 70 dB
Temperature Stability 0 - 50 ºC +/- 5x10-9
Mechanical Tuning +/- 1x10-6
Electrical Tuning +/-5VDC +/- 2x10-7
Stability Allan Variance τ=1s 1E-12
Phase Noise 1 Hz
10 Hz
100 Hz
1 kHz
10 kHz
-112
-142
-160
-167
-170
-109
-138
-156
-165
-166
dBc/Hz
Spurious - -120 -110 dBc
Absolute Maximum Ratings
RF power on tuning port +20dBm Maximum
DC Voltage on tuning port +/-10 VDC Maximum
RF Power on outputs +20dBm Maximum
DC Voltage on outputs 50 VDC Maximum
Storage Temperature -10 to +75 ºC
Operation Environment 0 to +50 ºC
Chassis 2U H, 19 “ W, 16” D
Specifications
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The LNFR-100E is warranted to be free of defects under normal operating
conditions, as specified, for one year from date of original shipment from
SpectraDynamics, Inc (SDI). SDI’s obligation and liability under this warranty is
expressly limited to repairing or replacing, at SDI’s option, any product not meeting the
said specifications. This warranty shall be in effect for one (1) year from the date an
LNFR-100E is sold by SDI. SDI makes no other warranty, express or implied, and
makes no warranty of the fitness for any particular purpose. SDI’s obligation under this
warranty shall not include any transportation charges or costs of installation or any
liability for direct, indirect, or consequential damages or delay. Any improper use,
operation beyond capacity, substitution of parts not approved by SDI, or any alteration or
repair by others in such manner as in SDI’s reasonable judgement affects the product
materially and adversely shall void this warranty. No employee or representative of SDI
is authorized to change this warranty in any way or grant any other warranty.
SDI
Warranty
SDI
SPECTRADYNAMICS,INC •1849 Cherry St Unit 2.. •Louisville, CO 80027 •Phone: [phone] •Fax: [phone]
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