Time Machines TM2503A 10MHz and 1PPS Distribution Amplifier User Manual
- June 9, 2024
- TIME MACHINES
Table of Contents
TM2503A
10MHz and 1PPS Distribution Amplifier Installation and Operation Manual
v1.0
TimeMachines Inc.
300 South 68th Street Place, Suite 100
Lincoln, NE 68510
402-486-0511
Email: tmsales@timemachinescorp.com
Engineered and Manufactured in Lincoln, Ne, USA
Introduction
The TM2503A is a 3 channel distribution amplifier that can distribute 1PPS and
10MHz signals from other TimeMachines time server products. It is well
matched to the TM2500C when the need to distribute the 10MHz signal to distant
equipment is needed. It resides in the same form factor as the TM2500C and can
be mounted in the same rack mount panels making for a clean installation.
The TM2503A contains filtering to turn the 3.3V TTL square wave 10MHz signal
into a low distortion sine wave. 50Ohm inputs and outputs are standard. Clean
sine waves travel much more reliably on coaxial cable across longer distances.
The 1PPS signal is not filtered, but having 3 separate drivers allows a wider
distribution of the 1PPS signal if required. The TM2503A has a selection
switch that switches the signal path between the 1PPS and 10MHz modes. It is
powered from a single 12V supply and provides isolated outputs.
Front panel indications for 10MHz Out of Range, 10MHz Good, 1PPS, and Power
provide functional information with a quick glance. Input and output
connections are made through standard BNC connectors located on the back of
the device.
Installation
Physical Mounting
The TM2503A can be left as a stand-alone table top device or can be mounted in a rack using the TimeMachines 760-022-000 or 760-023-000 rack mount adapter plates. Rubber feet are included if the user wishes to place the device on a table top.
Power
The TM2503A runs on 12V DC power. The connector is a 5.5/2.5mm center positive connector. Other 12V sources can be used as well if more convenient. Input range is 7-18V DC.
Front Panel Indications and Controls
The front panel of the TM2503A has 4 indicator LEDs:
- IN OOR – Input Out of Range. This red LED indicator lights when in the 10MHz mode and the input signal is not in the prescribed functional range.
- IN OK – Input signal is OK. This green LED indicator lights when in the 10MHz mode and the input signal is in the acceptable range.
- 1PPS – 1 Pulse Per Second detect. This yellow LED indicator functions as a indication that a 1PPS signal has been detected on the input.
- POW – Power LED. This green LED lights when input power is applied.
- 10MHz – 1PPS Slide Switch. This switch is moved to set the signal processing mode of the device. Signal paths are altered by the switch and active circuitry is moved to support the desired type of signal.
Connection Diagram
Power
The 12V power supply included with the TM2503A is connected to the back panel power jack.
Input
The Input of the TM2503A is typically connected to either a 10MHz oscillator source, or a 1PPS signal.
Output 1, 2, and 3
The outputs of the TM2503A when in 10MHz mode, are transformer coupled
isolated 50Ohm outputs.
Typical connection is with a 50 Ohm coaxial cable between the TM2503A and
other pieces of test equipment. The outputs of the TM2503A when in 1PPS mode
are optically isolated.
Basic Theory of Operation
Input Section
The input signal, 10MHz or 1PPS enters through the BNC connector. The path of signal is then split based on the position of the slide switch. If the switch is in the 1PPS position, that path will be followed. The 10MHz position follows a different path with additional signal conditioning.
1PPS Path
The 1PPS path is significantly simpler than the 10MHz path as there is no
filtering of the signal. It is treated as a logic signal through the device.
Once the path is split at U8, the signal enters an optical isolation logic
device, U17. The output of the opto-isolator then feeds three separate N and
P channel Mosfet arrays, U19, U20, and U22, which are powered from an
internally generated and isolated power supply created by U16 and T5. The
outputs of these MOSFET arrays are then fed through the 1PPS path of Relays K1
and K2. From there, the signals go to the three separate output BNC
connections.
Some small crossover distortion can be seen at high measurement rates on the
1PPS outputs from the MOSFET drivers.
10MHz Path
The 10MHz path, post 1PPS/10MHz path selection switch U8, enters a 10MHz
bandpass filter to convert the square wave to a sine wave. The output of the
filter is transformer coupled through HY1 to an RMS detector that is used to
update the display LEDs. In addition the filtered signal is passed to a set
of three amplifiers, U2-U4, whose outputs are then passed through a 15MHz low
pass filter stage.
The outputs of the amplifiers and then passed through three transformers,
T1-T3, and then to the three BNC outputs.
Specifications
Input
• Voltage Range | 7-18V DC |
---|---|
• Frequency Range | 10MHz +/- 1% / 1 Hz |
• Input Signal Range, 10MHz | 0 to +16dBm, 0.8 to 4Vpp, into 50Ohms |
• Input Signal Range, 1PPS | 2.2 Vpp to 5Vpp |
• Input Impedance | 50Ohm +/-5.5% |
• Input Coupling | Series LC (Open at DC) |
Output
• Waveform | Sine |
---|---|
• Level | +13dBm +/- 1dBm |
• Impedance | 50Ohm +/-5% |
• Isolation | >13dB |
• Coupling | Transformer |
• Harmonic Level | >34 dBc |
• Bandwidth | +/- 2.8MHz (-3dB) |
• 1PPS | 3.3V TTL compatible |
Miscellaneous
• Connection, Power | 5.5/2.5mm center positive |
---|---|
• Connections, Signal | BNC female, 1 In, 3 Out |
(Specifications are subject to change without notice)
Installation and Operations Manual
Web / timemachinescorp.com Email /
tmsales@timemachinescorp.com Phone /
402-486-0511