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FREQUENCY CONVERTERS & REPEATERS

designs built to your specifications

Frequency converters are used to shift a signal from one center frequency to another, even down to "zero frequency" (or baseband). They are found in almost all receivers and transmitters as well as repeaters and frequency multiplexers. The main system blocks consist of frequency synthesizers (phase locked oscillators), frequency mixers, amplifiers and filters. Frequency conversion can be coherent (i.e. phase locked to a central frequency standard) or incoherent, depending on the application. Frequency converters can be integrated into a complete radio system or as stand-alone units for use in modular systems (e.g. satellite ground stations, channel multiplexers, etc.).


Baseband and single-sideband frequency converters rely on "vector" conversion using an I,Q mixer and a synthesized local oscillator. These converters can be designed for upconversion and downconversion. Common stand-alone applications include baseband-to-IF conversion and frequency division multiplexing systems.


Repeaters are often used to increase radio coverage over a defined area. They receive a signal and, using a frequency converter, rebroadcast the same signal on a different center frequency. They are found in all types of communication – space ("bent-pipe" transponders for broadcasting, telecom), telephony (both backhaul and mini base stations), data (e.g. WiFi, WiMax, etc.), broadcasting, amateur radio, emergency communications, etc. and are useful in environments where radio communication is difficult (remote locations, urban canyons, mountainous regions, indoor environments, etc.). Come to us with your special radio communication requirements.

Baseband to 70/140/160 MHz IF Up and Down Converter Series

Application


This high end 5.2GHz RF Front end has been developed for use in a spread spectrum radio working according to the W-CDMA (UTRA) standard. A cavity duplexer yields very high transmit/receive isolation allowing full duplex operation and high rejection of out-of-band signals while maintaining low insertion loss for best possible receiver noise figure. Oscillators with PDROs and a high stability reference oscillator assure an extremely good phase noise and a very stable frequency.




Configurations


The front end can be configured with or without duplexer. Depending on the standard, different power levels are possible, range from mW to several W (or more).




Operation


The transmitter features :
• Filtering of the transmit IF signal

• Up conversion of the transmit IF signal to 5.2 GHz
• Power amplification of the signal
• Transmission power level control
The receiver features :
• Amplification and filtering of the incomingantenna signal
• Down conversion of the antenna signalfrom 5.2 GHz to IF
• Receiver automatic gain control
• All the local oscillators are locked to ahigh stability OCXO.
• Parts with excellent phase noise arechosen.




Key Features


• Covers 5..5.2GHz Band
• Low Noise Figure
• Double conversion
• High Stability
• Very good phase noise
• High Power
• High TX/RX Isolation




Options


High power amplifier
Mechanical duplexer to achieve very high transmit/receive isolation.
Mechanical Filters for low insertion loss and high rejection.
Oscillators with PDRO’s for extremely good phase noise.
High stability reference oscillator.




Specifications for a Standard Unit:


These can be modified to meet your specific requirements.





70/140/160 MHz to IQ Up and Down Converter Series

Application


This series of units converts an industry standard 70, 140 or 160 MHz IF signal to I and Q baseband signals. These units are often used in satellite ground stations and applications where an IQ interface is needed between RF up and/or down converters and a signal processing subsystem.




Configurations


This specific version of the converter is built on a PC/104 form factor (90 by 96
mm) board. The unit is fitted with PC/104, 40 and 64-way stack-through and SMA type connectors. While the unit shown is a downconverter, full duplex up and down converters can be supplied. The IF input connector is a female SMA, PCB mounted connector. The I and Q outputs are routed via the PC/104 stackthrough connectors. This specific unit has
a sample and hold amplifier that can be triggered through the PC/104 bus. This version of the downconverter will convert a 70 MHz IF signal of -30 dBm (20mVpp in 50 Ω) to I and Q signals of ± 5 Vpp. The overall gain of this specific unit is 50 dB. Low pass filters clean up the I and Q signals. Units with different in and output power levels can be supplied upon request.




Local Oscillator


The local oscillator is running at the double IF frequency and is built around
a PLL and VCO. The LO can be set in 10 KHz frequency steps. The frequency reference is a 13 MHz TCXO (± 2.5 ppm over a -25 to +75° C temperature range). A highly stable OCXO (0.1 ppm) can be supplied upon request. Custom channel spacing can be configured and the local oscillator can be built using multipliers and an OCXO instead of a PLL providing an extremely low phase noise. In configurations where multiple converters are stacked to form a single IF subsystem, all local oscillators can be locked to a single internal or external frequency reference. Switching between internal and external reference is automatic.




Key Features


• Series of full duplex IF to IQ frequency converters
• Wide range of IF SAW filter bandwidths
• PC/104 compliant or 19” plug in modules
• Internal or external power supplies
• On board or external TCXO or OCXO frequency reference
• Programmable local oscillators
• Redundant and hot pluggable power supplies available
• Subsystem controller with Ethernet interface available




Interface


The converter is programmed through a TTL port. RS232 or Ethernet interfaces can be added. Local oscillator frequency and attenuator settings are stored in non volatile memory in the on board microprocessor. The processor can be set to send status bytes and alarms (like power supply failures, local oscillator unlock and external reference frequency status) through the interface port. The processor code can be upgraded in the field.




Options


Various standard units are available and a wide range of options like AGC, ALC, and a 19” form factor exist. Standard IF connectors are SMA female; other types like SMC or BNC are available upon request. More powerful processors like an ARM9 have been integrated in some versions of these converters providing additional on board signal processing. Many custom versions have been built and we will modify these converters to meet your specific requirements.




Specifications





Optional Custom Modifications:


Highly stable 10 MHz frequency reference (0.1 ppm, OCXO)
Input for external frequency reference
Multiple units connected to a single frequency reference
Hot swappable converters
Other than 10 KHz IF channel spacing
Non-standard IF frequencies
IQ to 140, 160 MHz or other IF frequency
AGC and/or ALC
Built in DC/DC converter
Redundant power supplies
Other than PC/104 form factor
FCC part 15B class A compliant
IESS-308/309 compliant
*If you have different requirements for a similar design or a completely new set of requirements, please contact us at the numberslisted below or via mail or refer to the sales page on our website for arepresentative in your area.*





L-Band Satellite Modem with Integrated GPS Receiver

Application


This L-Band modem is part of an asset tracking system.




Architecture


In this product, a classic up and down converter architecture was selected over
direct conversion. The transmit part of the RF subsystem receives an IF of 455 kHz, which is then converted to L-Band. The 455 kHz TX signal is mixed up to 225 MHz where a narrow band SAW filter rejects any unwanted signals. This signal is then mixed up to a channel in the 1.626 to 1.660 GHz frequency range. Custom ceramic type RF filters reject the out-of-band signals. On the receive side, a signal in the 1.525 to 1.559 GHz frequency range is mixed down to 225 MHz where it is filtered by a narrow band SAW filter. This signal is subsequently mixed down to an IF of 455 kHz. An AGC amplifier increases the IF power signal to a level that is optimized for the A/D. In the receiver line, a power splitter feeds a part of the antenna RF signal to an on board GPS engine. The receiver and transmitter have separate antennas. The receive antenna has an integrated LNA that covers both the L-Band downlink space segment and the GPS L1 band. The SSPA for the uplink is integrated with the transmit antenna. This assures maximum output power with the lowest cost SSPA part. A high efficiency, switched mode power supply is integrated with the SPPA and also mounted on the back of the antenna.




Key Features


• Design uses dual up and down conversion
• Zero IF architecture available for lower parts count
• Transceiver is half duplex
• Full duplex optional
• Highly efficient switched mode power supply allows wide input voltage range
• LNA integrated with receive antenna
• SSPA integrated with transmit antenna




Specifications


*If you have different requirements for a similar design or a completely
new set of requirements, please contact us at the numbers
listed below or via mail or refer to the sales page on our website for
a representative in your area.*




Optional Custom Modifications:


Full duplex
Other frequency ranges in L-Band
S-Band, C-Band
Integrated LNA and SSPA
Zero IF architecture
Lower phase noise
Other channel spacing
Higher transmitter power levels





C-Band Converter

Application


This high end 5.2GHz RF Front end has been developed for use in a spread spectrum radio working according to the W-CDMA (UTRA) standard. A cavity duplexer yields very high transmit/receive isolation allowing full duplex operation and high rejection of out-of-band signals while maintaining low insertion loss for best possible receiver noise figure. Oscillators with PDROs and a high stability reference oscillator assure an extremely good phase noise and a very stable frequency.




Configurations


The front end can be configured with or without duplexer. Depending on the standard, different power levels are possible, range from mW to several W (or more).




Operation


The transmitter features :
• Filtering of the transmit IF signal

• Up conversion of the transmit IF signal to 5.2 GHz
• Power amplification of the signal
• Transmission power level control
The receiver features :
• Amplification and filtering of the incomingantenna signal
• Down conversion of the antenna signalfrom 5.2 GHz to IF
• Receiver automatic gain control
• All the local oscillators are locked to ahigh stability OCXO.
• Parts with excellent phase noise arechosen.




Key Features


• Covers 5..5.2GHz Band
• Low Noise Figure
• Double conversion
• High Stability
• Very good phase noise
• High Power
• High TX/RX Isolation




Options


High power amplifier
Mechanical duplexer to achieve very high transmit/receive isolation.
Mechanical Filters for low insertion loss and high rejection.
Oscillators with PDRO’s for extremely good phase noise.
High stability reference oscillator.




Specifications for a Standard Unit:


These can be modified to meet your specific requirements.





S-Band Converter

Application


This L-Band modem is part of an asset tracking system.




Architecture


In this product, a classic up and down converter architecture was selected over
direct conversion. The transmit part of the RF subsystem receives an IF of 455 kHz, which is then converted to L-Band. The 455 kHz TX signal is mixed up to 225 MHz where a narrow band SAW filter rejects any unwanted signals. This signal is then mixed up to a channel in the 1.626 to 1.660 GHz frequency range. Custom ceramic type RF filters reject the out-of-band signals. On the receive side, a signal in the 1.525 to 1.559 GHz frequency range is mixed down to 225 MHz where it is filtered by a narrow band SAW filter. This signal is subsequently mixed down to an IF of 455 kHz. An AGC amplifier increases the IF power signal to a level that is optimized for the A/D. In the receiver line, a power splitter feeds a part of the antenna RF signal to an on board GPS engine. The receiver and transmitter have separate antennas. The receive antenna has an integrated LNA that covers both the L-Band downlink space segment and the GPS L1 band. The SSPA for the uplink is integrated with the transmit antenna. This assures maximum output power with the lowest cost SSPA part. A high efficiency, switched mode power supply is integrated with the SPPA and also mounted on the back of the antenna.




Key Features


• Design uses dual up and down conversion
• Zero IF architecture available for lower parts count
• Transceiver is half duplex
• Full duplex optional
• Highly efficient switched mode power supply allows wide input voltage range
• LNA integrated with receive antenna
• SSPA integrated with transmit antenna




Specifications


*If you have different requirements for a similar design or a completely
new set of requirements, please contact us at the numbers
listed below or via mail or refer to the sales page on our website for
a representative in your area.*




Optional Custom Modifications:


Full duplex
Other frequency ranges in L-Band
S-Band, C-Band
Integrated LNA and SSPA
Zero IF architecture
Lower phase noise
Other channel spacing
Higher transmitter power levels